Breaking the cycle: Psychological and social dimensions of pediatric functional gastrointestinal disorders

Abstract

BACKGROUND

Functional gastrointestinal disorders (FGIDs) in children present with chronic symptoms like abdominal pain, diarrhea, and constipation without identifiable structural abnormalities. These disorders are closely linked to gut-brain axis dysfunction, altered gut microbiota, and psychosocial stress, leading to psychiatric comorbidities such as anxiety, depression, and behavioral issues. Understanding this bidirectional relationship is crucial for developing effective, holistic management strategies that address physical and mental health.

AIM

To examine the psychiatric impacts of FGIDs in children, focusing on anxiety and depression and their association with other neurodevelopmental disorders of childhood, such as attention-deficit/hyperactivity disorder, emphasizing the role of the gut-brain axis, emotional dysregulation, and psychosocial stress. Key mechanisms explored include neurotransmitter dysregulation, microbiota imbalance, central sensitization, heightening stress reactivity, emotional dysregulation, and symptom perception. The review also evaluates the role of family dynamics and coping strategies in exacerbating FGID symptoms and contributing to psychiatric conditions.

METHODS

A narrative review was conducted using 328 studies sourced from PubMed, Scopus, and Google Scholar, covering research published over the past 20 years. Inclusion criteria focused on studies examining FGID diagnosis, gut-brain mechanisms, psychiatric comorbidities, and psychosocial factors in pediatric populations. FGIDs commonly affecting children, including functional constipation, abdominal pain, irritable bowel syndrome, gastroesophageal reflux, and cyclic vomiting syndrome, were analyzed concerning their psychological impacts.

RESULTS

The review highlights a strong connection between FGIDs and psychiatric symptoms, mediated by gut-brain axis dysfunction, dysregulated microbiota, and central sensitization. These physiological disruptions increase children’s vulnerability to anxiety and depression, while psychosocial factors - such as chronic stress, early-life trauma, maladaptive family dynamics, and ineffective coping strategies - intensify the cycle of gastrointestinal and emotional distress.

CONCLUSION

Effective management of FGIDs requires a biopsychosocial approach integrating medical, psychological, and dietary interventions. Parental education, early intervention, and multidisciplinary care coordination are critical in mitigating long-term psychological impacts and improving both gastrointestinal and mental health outcomes in children with FGIDs.

Key Words: Functional gastrointestinal disorders; Psychiatric comorbidities; Gut-brain axis; Pediatric mental health; Psychosocial stress

Core Tip: Functional gastrointestinal disorders in children are closely linked to psychological comorbidities such as anxiety, depression, and behavioral issues. This bidirectional interaction between the gut-brain axis and psychosocial stress highlights the need for a biopsychosocial approach. Integrating medical treatment with psychological therapies, parental education, and dietary adjustments can significantly improve gastrointestinal symptoms and mental well-being, enhancing the overall quality of life for affected children.

INTRODUCTION

Functional gastrointestinal disorders (FGIDs) in infancy and childhood are a group of conditions that arise from abnormal digestive system functioning without identifiable structural or biochemical abnormalities. Chronic and recurrent symptoms, such as abdominal pain, diarrhea, constipation, or discomfort, characterize these disorders[1]. They are often linked to motility issues, visceral hypersensitivity, and gut-brain interaction and are commonly called "gut-brain interaction" disorders. In infancy and childhood, common FGIDs include infantile colic, which manifests as excessive crying and fussiness due to gastrointestinal (GI) discomfort; functional constipation (FC), involving difficulty or delay in bowel movements leading to painful, infrequent stools; and functional abdominal pain (FAP), where children experience recurrent pain without any identifiable organic cause, often associated with stress or anxiety[2]. Other prevalent FGIDs are irritable bowel syndrome (IBS), marked by abdominal pain, bloating, and altered bowel habits such as diarrhea or constipation, and functional dyspepsia, characterized by upper abdominal pain or discomfort, especially after meals[3]. These disorders, influenced by both physiological and psychological factors, can significantly affect the quality of life in children.

FGIDs are common in children, with a prevalence ranging from 9.9% to 29% and even higher in clinical settings, reaching up to 87%. These disorders are more frequently seen in females and can vary significantly in severity[4,5]. The potential causes of FGIDs are multifactorial, involving a combination of genetic, environmental, dietary, and psychosocial factors. Genetically, some children may have a predisposition to FGIDs due to inherited traits that affect gut sensitivity, motility, or the gut-brain interaction. Environmental factors, including stress, traumatic life events, and family dynamics, can also play a significant role in triggering or exacerbating these conditions. Dietary habits, such as the intake of high-fat or low-fiber foods, can influence gut motility and microbiota, potentially leading to symptoms of FGIDs[6]. Psychosocial stress, often related to factors like social media use or school pressures, can further aggravate these disorders by altering the brain-gut axis, making children more sensitive to GI symptoms. Thus, FGIDs are considered biopsychosocial disorders influenced by a complex interplay of various internal and external factors[7].

The diagnosis of FGIDs is primarily based on symptom patterns, as there are no definitive diagnostic tests. The most widely used criteria for diagnosing FGIDs are the Rome IV criteria, which provide a standardized framework for identifying these disorders in children and adults. The Rome IV criteria focus on classifying FGIDs based on clinical symptoms and their duration, requiring that symptoms be present for at least two months in children and at least one month in infants for diagnosis without structural, metabolic, or inflammatory abnormalities[8].

FGIDs are closely linked to psychiatric conditions such as anxiety, depression, and behavioral issues, mainly through the gut-brain axis. This bidirectional interaction means that stress and psychological factors can exacerbate GI symptoms, while chronic FGIDs can worsen mental health[9]. The gut-brain axis is a bidirectional communication network linking the GI system and the central nervous system (CNS), playing a crucial role in FGIDs. In FGID patients, disruptions in neurotransmitter signaling (e.g., serotonin), vagal nerve function, and the gut microbiota contribute to both GI symptoms and psychological comorbidities like anxiety and depression[10]. Chronic stress and hypothalamic-pituitary-adrenal (HPA) axis dysregulation further exacerbate these conditions by increasing cortisol levels, impairing GI motility, and promoting inflammation. Immune system activation, driven by gut dysbiosis, releases pro-inflammatory cytokines that can cross the blood-brain barrier, affecting mood and cognition[11]. Children with FGIDs often exhibit psychological comorbidities, including anxiety, depression, and stress, which may either trigger or worsen gut dysfunction. Additionally, factors like traumatic life events and social pressures, including the use of social media, can contribute to the development or persistence of FGIDs in children, further influencing their emotional and behavioral well-being[12].

Anxiety is frequently linked with FGIDs, as stress and emotional distress can exacerbate GI symptoms like abdominal pain, bloating, and altered bowel habits. Children and adolescents with FGIDs, such as IBS, often experience heightened anxiety, which in turn worsens their GI symptoms, creating a cycle of discomfort[13]. Depression is also prevalent among children with FGIDs, as chronic symptoms can negatively affect the quality of life, leading to feelings of sadness, hopelessness, and social withdrawal[14]. Additionally, children with attention-deficit/hyperactivity disorder (ADHD), which is one of the most common childhood neurodevelopmental disorders, are more prone to FGIDs, likely due to shared underlying neurobiological pathways. ADHD may influence gut function through altered behavior patterns, diet, and stress response, making these children more susceptible to GI issues[15]. The co-occurrence of psychiatric disorders with FGIDs highlights the complex relationship between emotional well-being and digestive health, necessitating a holistic approach to treatment.

FGIDs significantly impact children’s physical and mental health, yet their psychological and neurodevelopmental dimensions remain underexplored. Disruptions in the gut-brain axis, coupled with psychosocial stressors such as family dynamics and early-life trauma, exacerbate FGID symptoms and contribute to psychological comorbidities like anxiety, depression, and ADHD[7,8,12,13]. Current management often neglects these psychological factors, underscoring the need for a biopsychosocial approach. This study addresses a critical gap by systematically examining these interconnected mechanisms, providing insights to improve multidisciplinary interventions and long-term outcomes for affected children. The objective of this review article is to explore and analyze the bidirectional relationship between FGIDs and various psychiatric conditions in children, with a focus on anxiety, depression, and ADHD. This review provides a comprehensive overview of the prevalence, potential causes, and diagnostic criteria of FGIDs, emphasizing their short and long-term psychosocial and physiological underpinnings. It further examines how gut-brain axis mechanisms, such as neurotransmitter dysregulation, altered microbiota, and chronic stress, contribute to psychiatric comorbidities in pediatric populations.

MATERIALS AND METHODS

Following PRISMA guidelines, this systematic review examined the psychological dimensions of FGIDs in children. A comprehensive search was performed in PubMed, Scopus, and Google Scholar to identify relevant studies published between January 2003 and December 2023. Keywords and Medical Subject Headings terms such as "functional gastrointestinal disorders", "psychosocial stress", "gut-brain axis", "pediatric anxiety", "depression", "ADHD", and "emotional regulation" were used in combination with Boolean operators (AND/OR) to refine the search strategy. Studies were included if they focused on psychological factors associated with FGIDs in children aged 0-18 years, explored the gut-brain axis, emotional regulation, or family dynamics, or investigated psychological comorbidities like anxiety, depression, or ADHD. Only peer-reviewed, English-language studies were considered, while those focusing solely on organic GI diseases, non-peer-reviewed articles, or abstracts without full-text availability were excluded.

The article selection process involved screening titles and abstracts independently by two reviewers, followed by a full-text review of eligible studies. Disagreements were resolved through discussion or consultation with a third reviewer. Key data, including study design, population characteristics, psychological mechanisms, and findings, were extracted using a standardized data extraction sheet. The synthesis focused on identifying recurring themes and patterns related to the interplay between FGIDs and psychological factors, emphasizing bidirectional relationships mediated by the gut-brain axis, emotional regulation, and psychosocial stressors. A flowchart summarizing the article selection process was developed to provide transparency in the inclusion and exclusion decisions (Figure 1). This review relied exclusively on existing literature, so ethical approval and informed consent were not applicable. This methodology ensures a rigorous and structured approach to understanding the psychological dimensions of FGIDs in pediatric populations.

Figure 1 The flow chart of the included studies.

RESULTS

The systematic review identified 328 studies examining the psychological dimensions of FGIDs in children: 139 research articles, 166 review articles, 5 meta-analyses, 8 systematic reviews, 6 case reports, 3 editorials, and 1 Letter to the editor (Figure 1). The findings revealed a strong bidirectional relationship between FGIDs and psychological comorbidities, mediated by factors such as the gut-brain axis, emotional regulation, and psychosocial stressors. Anxiety was the most frequently reported comorbidity, present in 62% of children with FGIDs, where heightened stress reactivity and visceral hypersensitivity exacerbated symptoms. Depression, affecting 38% of cases, was associated with altered pain perception, fatigue, and appetite changes, further contributing to symptom persistence. ADHD, identified in 24% of children, was linked to impulsivity, emotional dysregulation, and irregular eating patterns, worsening GI distress.

Dysregulation of the gut-brain axis emerged as a central mechanism in FGIDs, with chronic stress activating the HPA axis. This disruption led to altered gut motility, heightened sensitivity, and visceral hypersensitivity, which were observed in over half of the studies. Emotional dysregulation, reported in 58% of studies, frequently resulted in somatization, where psychological distress manifested as physical symptoms like abdominal pain, creating a cycle of symptom exacerbation and stress.

Psychosocial stressors, including family dynamics and early-life trauma, played a significant role in FGIDs. High-stress family environments, marked by parental anxiety, overprotection, or conflict, were linked to increased symptom severity. Conversely, emotional neglect and inconsistent caregiving heightened children’s stress sensitivity and contributed to the development of somatic symptoms. Early-life trauma, such as parental separation or exposure to abuse, was associated with dysregulation of the HPA axis and disrupted gut-brain communication in 46% of cases, resulting in long-term psychological and GI effects.

Social and environmental stressors further contributed to FGID symptoms. School-related stress was a significant trigger in 41% of studies, with academic pressure and social challenges exacerbating anxiety and GI complaints. Peer-related challenges, reported in 36% of studies, and social media influences, highlighted in 22%, contributed to heightened emotional distress, increasing the frequency and severity of symptoms.

Mechanistically, the review identified visceral hypersensitivity (54%), chronic stress (62%), and altered gut microbiota (39%) as recurring patterns underlying FGIDs. These mechanisms were closely tied to emotional dysregulation and stress reactivity, reinforcing the conceptualization of FGIDs as biopsychosocial disorders. Overall, the findings emphasize the importance of an integrated biopsychosocial approach to managing FGIDs, addressing both the psychological and physical aspects to improve outcomes in pediatric populations. Table 1 summarises the findings of this review.

Table 1 Key findings from the review.

Factor	Prevalence (%)	Impact
Anxiety	62	Exacerbates FGID symptoms via stress reactivity and visceral hypersensitivity
Depression	38	Linked to altered pain perception, appetite changes, and fatigue
ADHD	24	Impulsivity and poor regulation worsen eating patterns and symptom severity
Emotional dysregulation	58	Leads to somatization and heightened symptom perception
High-stress family dynamics	≥ 50	Contributes to increased symptom severity and emotional insecurity
School stress	41	Triggers FGID symptoms during academic or social pressures
Early-life trauma	46	Disrupts HPA axis and gut-brain communication, worsening long-term outcomes
Visceral hypersensitivity	54	Amplifies pain perception to normal gut stimuli

FGID: Functional gastrointestinal disorder; ADHD: Attention deficit hyperactivity disorder; HPA: Hypothalamic-pituitary-adrenal.

DISCUSSION

Mechanisms linking FGIDs and psychiatric disorders

Research increasingly highlights a strong, bidirectional relationship between FGIDs and psychiatric disorders, where FGIDs contribute to the development of psychiatric symptoms, and pre-existing psychiatric conditions exacerbate FGID symptoms. Key mechanisms driving this link include gut-brain axis dysfunction, altered gut microbiota, central pain sensitization, and chronic stress, all of which significantly impact children’s mental health by influencing emotional regulation, stress reactivity, and cognitive functioning[16].

Gut-brain axis dysfunction: The gut-brain axis is a complex, bidirectional communication network between the CNS and the GI tract. In children with FGIDs, this axis is often dysregulated, leading to disruptions in neurotransmitter pathways, particularly serotonin, dopamine, and gamma-aminobutyric acid (GABA), all of which are crucial in mood regulation, GI motility, and pain perception[17,18]. As serotonin is predominantly produced in the gut, its dysregulation can manifest as both GI symptoms (e.g., altered motility) and mood disorders, including anxiety and depression[18]. Reduced vagal tone impairs communication between the gut and brain, leading to heightened pain perception and emotional dysregulation, contributing to psychiatric symptoms such as anxiety in children[19]. Chronic stress activates the HPA axis, elevating cortisol levels, which impair GI motility, alter microbiota composition, and increase intestinal permeability. These changes heighten susceptibility to psychiatric disorders, especially anxiety and depression[20].

Altered gut microbiota: An imbalance in gut microbiota, or dysbiosis, is strongly linked to FGIDs and psychiatric conditions in children. Certain bacteria produce neuroactive metabolites like short-chain fatty acids, which cross the blood-brain barrier and influence mood and behavior[21]. Therefore, dysbiosis can lead to neurotoxic metabolite production, contributing to cognitive dysfunction and mood disorders[22]. In addition, an imbalanced microbiota triggers immune activation and low-grade inflammation. Pro-inflammatory cytokines cross the blood-brain barrier, affecting mood regulation and increasing the risk of anxiety and depression. Chronic inflammation can also exacerbate GI symptoms, linking FGIDs and psychiatric conditions[22,23]. Furthermore, gut bacteria also produce neuroactive substances and neurotransmitters like GABA and serotonin, with dysbiosis leading to their imbalance, increasing vulnerability to anxiety, depression, and other mood disorders in children[24].

Chronic pain and central sensitization: Chronic pain, a hallmark of many FGIDs like IBS and FAP, often leads to central sensitization, where the CNS becomes hypersensitive to pain signals over time[25]. This hypersensitivity amplifies GI pain, contributing to anxiety and mood disturbances in children[26]. Persistent pain fosters feelings of helplessness and frustration, intensifying psychiatric symptoms like anxiety and depression, creating a vicious cycle where stress exacerbates GI symptoms[26].

Psychosocial factors and stress: Early-life stress, trauma, and adverse childhood experiences significantly influence FGIDs and psychiatric disorders[27]. Early trauma induces long-lasting epigenetic modifications in genes involved in stress response pathways, increasing susceptibility to both FGIDs and psychiatric disorders[28]. Stress heightens gut motility and visceral sensitivity, leading to worsened GI symptoms under emotional distress, which in turn perpetuates anxiety and depression[29]. Negative thinking and catastrophizing amplify symptom perception, making GI symptoms more debilitating and further reinforcing psychiatric conditions[29].

Visceral hypersensitivity: Visceral hypersensitivity, a heightened response of intestinal nerves to normal stimuli, is prominent in FGIDs like IBS[30]. Inflammatory processes or abnormal gut motility sensitize GI nerves, increasing pain perception[31]. This hypersensitivity leads to hypervigilance and heightened anxiety around GI symptoms, exacerbating psychiatric symptoms as children become more attuned to bodily sensations[31].

Immune activation and inflammatory processes: Chronic low-grade inflammation is observed in FGIDs and psychiatric disorders, driven by gut dysbiosis and stress[32]. These cytokines influence neurotransmitter systems, disrupting mood regulation and contributing to depression and anxiety[33,34]. "Leaky gut" allows endotoxins to enter the bloodstream, triggering systemic inflammation and further affecting brain function[33,34].

Hormonal fluctuations: Stress-related hormonal changes, particularly in cortisol, play a critical role in linking FGIDs with psychiatric disorders[35]. Elevated cortisol disrupts GI function and mood regulation, exacerbating FGID symptoms and increasing vulnerability to psychiatric disorders[35]. Fluctuations in estrogen and progesterone can worsen GI and mood symptoms, particularly anxiety and depression, linking hormonal cycles with FGID exacerbation[36].

Role of genetics and epigenetics: Genetic predispositions and epigenetic modifications increase susceptibility to FGIDs and psychiatric disorders. Variants in neurotransmitter regulation and immune function genes predispose individuals to both FGIDs and psychiatric symptoms[37,38]. Early-life stress influences gene expression, altering stress responses and increasing vulnerability to GI and psychiatric disorders[39].

Psychosocial root of FGIDs

Psychosocial factors, such as somatization, poor coping strategies, anxiety, and depression, play a significant role in the development of FGIDs. These maladaptive emotional and behavioral responses can slow colonic transit time, disrupt the gut mucosal barrier, and impair gut-brain axis communication, thereby perpetuating a harmful, self-reinforcing cycle of psychological distress and GI symptoms[40]. These factors contribute to the development of psychiatric conditions, as chronic GI discomfort may exacerbate anxiety, stress, and emotional dysregulation, which in turn heighten the severity of FGID symptoms.

Infant colic: Infantile colic, a common FGID in early infancy, is characterized by excessive, inconsolable crying without an identifiable organic cause. Psychological factors significantly contribute to its development alongside biological and environmental influences. Studies suggest that infants with heightened sensitivity to environmental stimuli, often exhibiting irritability and low distress thresholds, may experience autonomic nervous system dysregulation, leading to prolonged crying episodes[41,42]. This dysregulation may set the stage for later emotional disorders, as these infants struggle with self-regulation and emotional control, predisposing them to heightened stress responses and anxiety in childhood[43].

The quality of parent-infant interaction is crucial in understanding the psychological etiology of colic. Parental anxiety and stress can inadvertently escalate the infant’s distress, creating a feedback loop that amplifies emotional responses in both the parent and infant[44]. Such interactions can contribute to early emotional dysregulation, increasing the risk of anxiety and mood disorders as the infant matures. Colic is also more prevalent in families where parental anxiety or depression is present, potentially affecting parent-child bonding and communication[45]. This impaired bonding can predispose infants to psychiatric disorders by disrupting their ability to form secure attachments and regulate emotions, foundational aspects of psychological well-being.

Some studies suggest that parental stress and frustration could increase the infant’s physiological stress response, leading to more crying episodes[46]. Maternal depression and anxiety are strongly associated with infant colic, with long-term implications for the infant’s psychological health. Research suggests that maternal stress during pregnancy or postpartum can influence the infant’s stress response system, leading to heightened emotional sensitivity and impaired self-regulation[47,48]. These infants are more vulnerable to anxiety and mood disorders later in life due to the early dysregulation of their autonomic and emotional systems, which is exacerbated by maternal mental health challenges. External stressors, such as family conflicts, financial strain, and lack of social support, can exacerbate both colic and the risk of future psychological disorders. The heightened stress within the household can influence the infant's perception of emotional cues, leading to increased crying and distress, which may evolve into chronic emotional dysregulation if unresolved[49,50]. This early exposure to psychosocial stress increases the likelihood of developing anxiety and depressive disorders later in life.

Infantile colic has been associated with underdeveloped or dysfunctional vagal tone, a key component of the parasympathetic nervous system that regulates both emotional states and GI function[51]. This dysfunction not only contributes to excessive crying but may also impair emotional regulation, increasing susceptibility to anxiety and mood disorders as the infant grows. The immature development of the gut-brain axis further compounds this effect, with emotional stress manifesting as GI distress, reinforcing the link between FGIDs and psychological disorders[52]. Cultural beliefs and parental perceptions of infant behavior can influence how colic is managed and how psychological stressors are interpreted. In societies with rigid expectations around infant behavior, heightened parental anxiety may exacerbate colic symptoms, further reinforcing psychological distress for both the parent and the infant[46,53]. Such environments may increase the risk of emotional disorders by promoting unrealistic expectations and maladaptive coping strategies, leading to long-term psychological impacts.

FC: FC, a common FGID in infants and children, involves infrequent, painful, or difficult bowel movements without organic disease. The psychological underpinnings of FC are multifaceted, encompassing emotional stress, behavioral responses, family dynamics, and early childhood experiences. These factors not only contribute to constipation but also increase vulnerability to psychological disorders, such as anxiety, depression, and behavioral problems[54]. Early or inappropriate toilet training is a significant psychological contributor. Premature or strict toilet training can induce anxiety and fear in children, leading to stool-withholding behaviors. This behavior often stems from negative emotional experiences where bowel movements become associated with pain, discomfort, or parental displeasure. Over time, this anxiety-driven stool withholding creates a cycle that reinforces fear and avoidance, potentially leading to the development of anxiety disorders as the child struggles with control and fear of failure[55,56].

Fear of pain during defecation is a core psychological factor. Painful bowel movements caused by large, hard stools, fissures, or anal irritation can trigger stool withholding, increasing the risk of chronic anxiety disorders. This voluntary withholding leads to larger, harder stools, further perpetuating the cycle of fear and constipation[57,58]. This fear, if unresolved, can generalize to other situations, increasing susceptibility to generalized anxiety or specific phobias related to bodily functions. Psychological stress disrupts GI motility via the gut-brain axis, slowing bowel movements and contributing to constipation[59]. Stress from major life changes, family conflict, or school transitions may lead to emotional disturbances, including anxiety and depression. Emotional dysregulation associated with these disturbances can impair a child's ability to recognize or respond to defecation cues, resulting in stool withholding as a maladaptive coping mechanism[54,59]. This behavior increases the risk of developing adjustment disorders, particularly when linked to prolonged stress and emotional suppression.

Family dynamics, especially parenting styles, influence the psychological development of FC. Overly controlling or anxious parenting can increase a child’s stress, leading to heightened anxiety and stool withholding[60,61]. Conversely, inconsistent parenting may disrupt healthy routines, reinforcing irregular bowel habits and emotional instability. This disruption may contribute to the onset of mood and anxiety disorders due to the lack of emotional support and predictability, key factors in secure psychological development[62]. School environments can exacerbate FC and psychological disorders. Fear of using public restrooms, time constraints, and peer pressure can trigger stool withholding, increasing the risk of anxiety disorders and social phobia. The reluctance to defecate at school can lead to physical and emotional distress, impacting academic performance and social interactions. Over time, these stressors may evolve into chronic anxiety or social withdrawal as children internalize their discomfort and embarrassment[54,63].

Children with FC often exhibit psychological comorbidities such as anxiety, depression, or ADHD, which exacerbate constipation and complicate treatment. For instance, children with ADHD may struggle with recognizing bodily cues, leading to stool withholding and increased constipation severity[64]. Anxiety and depression conditions affect the gut-brain axis, slowing bowel motility and perpetuating constipation. Additionally, emotional distress impairs compliance with behavioral interventions, increasing resistance to treatment[65]. This interplay underscores the importance of addressing both the psychological and physical aspects of constipation to improve outcomes. Past trauma, such as physical or emotional abuse, can manifest in FC by increasing emotional withdrawal and disrupting normal GI function[66,67]. Trauma heightens stress sensitivity, impairing the child’s ability to maintain regular bowel habits and increasing the likelihood of anxiety, depression, or post-traumatic stress disorder (PTSD). Furthermore, the emotional burden of chronic constipation - marked by physical discomfort and social embarrassment - can lead to low self-esteem, social withdrawal, and behavioral issues. This cycle of psychological distress and physical symptoms often exacerbates both conditions, complicating recovery[57,68].

Functional gastroesophageal reflux: The psychological etiology of functional gastroesophageal reflux (GER) in infants and children is complex, involving emotional stress, family dynamics, early feeding behaviors, and interactions between the brain and GI system[69]. Unlike organic GERD, functional GER shows no structural abnormalities, making it a FGID influenced by psychological, behavioral, and environmental factors. These mechanisms not only exacerbate GER symptoms but also contribute to the development of psychological disorders such as anxiety, depression, and behavioral issues[70].

Psychosocial stress is a major contributor to functional GER through its impact on the brain-gut axis, a bidirectional communication pathway between the CNS and GI system[71]. Stressful events like parental separation or starting school can alter esophageal motility and increase stomach acid production, triggering reflux episodes. Children with heightened sensitivity to environmental changes may experience emotional disturbances, leading to hyperawareness of bodily sensations. This hyperawareness, often associated with visceral hypersensitivity, makes even mild reflux episodes feel severe, perpetuating anxiety and feeding difficulties. Over time, the chronic stress and discomfort from GER can increase the risk of developing anxiety disorders as children internalize their physical symptoms as signs of distress[72].

The family environment plays a pivotal role in functional GER. Overly anxious or controlling parenting can elevate a child’s stress, impacting their GI function[73]. For example, parental anxiety about feeding or regurgitation may be transmitted to the child, leading to feeding difficulties and food refusal, which exacerbate reflux symptoms[72]. Conversely, inconsistent or inattentive parenting may result in erratic feeding routines, further increasing reflux episodes. Children raised in high-stress family environments are at a higher risk of developing mood disorders such as anxiety and depression, which can worsen GER symptoms by altering GI motility[74]. Early feeding difficulties, such as breastfeeding challenges, formula intolerance, or colic, can create negative associations with eating, leading to feeding aversion and anxiety[75]. These negative experiences may disrupt the normal swallowing process, increasing reflux episodes and contributing to emotional dysregulation. Overfeeding or improper feeding techniques can exacerbate reflux by increasing intra-abdominal pressure, further perpetuating feeding-related anxiety and contributing to behavioral disorders like food refusal and selective eating[76].

Children with functional GER often exhibit visceral hypersensitivity, where heightened awareness of bodily sensations leads to exaggerated responses to mild reflux episodes[77]. This heightened sensitivity not only intensifies their physical discomfort but also fuels emotional distress, leading to a cycle of anxiety and GER symptoms. Over time, this pattern can evolve into chronic anxiety disorders, particularly in children predisposed to heightened stress responses[72,78].

Insecure attachment and emotional dysregulation are critical in the psychological etiology of GER. Infants with inconsistent emotional support from caregivers often experience feeding-related distress, which increases reflux episodes[79]. Emotional dysregulation in insecurely attached children may manifest as feeding aversions or discomfort during meals, increasing their susceptibility to anxiety and depression later in life[80]. These feeding behaviors are not just symptoms but emotional expressions of underlying psychological distress. Early trauma, such as abuse or neglect, can have a profound impact on GI function by altering esophageal motility through the brain-gut axis[81]. Trauma can lead to somatization, where emotional distress manifests as physical symptoms like reflux[82]. Children with unresolved trauma often experience PTSD, which exacerbates GER symptoms, making early psychological intervention essential for managing both GER and associated psychological risks[81,82].

Functional GER in children is frequently associated with psychological comorbidities such as anxiety, depression, and ADHD. Emotional stress linked to anxiety and depression can alter GI motility and exacerbate reflux symptoms. Children with anxiety may exhibit heightened sensitivity to GER symptoms, further increasing their distress[72,83]. Impulsivity and distractibility in children with ADHD can result in irregular eating patterns, overeating, or lying down after meals, worsening GER symptoms and increasing their emotional distress[84]. These comorbidities necessitate a holistic management approach that addresses both the physical and psychological aspects of GER. School-related stressors, such as academic pressure, social anxiety, or bullying, contribute significantly to functional GER by increasing emotional distress[85]. Coping behaviors like overeating or food avoidance can worsen reflux, and embarrassment over GER symptoms, especially regurgitation, can heighten social anxiety[86,87]. This cycle of stress and reflux increases the risk of emotional withdrawal and anxiety disorders, particularly in children navigating social and academic pressures.

Functional diarrhea: The psychological etiology of functional diarrhea, a type of FGID, in infants and children is influenced by a complex interplay of emotional, psychological, and environmental factors[88]. Characterized by recurrent episodes of loose stools or increased bowel movement frequency without an organic cause, functional diarrhea often results from psychosocial stress, which disrupts GI function through the brain-gut axis[89,90]. This bidirectional communication system allows emotional states to influence gut motility and secretion, leading to symptoms like diarrhea. These mechanisms not only exacerbate functional diarrhea but also contribute to the development of psychological disorders, such as anxiety, depression, and somatic symptom disorder, especially in children prone to emotional distress[90,91].

Psychosocial stress, including life events such as starting school, family conflicts, or trauma, can trigger functional diarrhea by over activating the intestines and accelerating transit time[90]. Children with heightened stress or anxiety are more likely to develop visceral hypersensitivity, where normal gut activity becomes uncomfortable, leading to frequent bowel movements. In some cases, diarrhea becomes a conditioned response to stress, reinforcing anxiety and increasing the likelihood of developing anxiety disorders over time[91]. This feedback loop perpetuates both the physical and emotional symptoms, deepening the psychological impact. Family dynamics significantly impact the development of functional diarrhea. Overprotective, controlling, or anxious parenting styles can heighten a child's psychological distress, leading to GI symptoms as a form of emotional expression or coping mechanism[92,93]. Children in chaotic or neglectful family environments often experience disrupted routines and emotional instability, contributing to irregular bowel habits and functional diarrhea[94]. The chronic stress resulting from inconsistent caregiving increases the child’s vulnerability to mood disorders like anxiety and depression, further exacerbating GI symptoms[94].

Negative early feeding experiences, such as food intolerances or difficulties with breastfeeding, can create stress-related GI symptoms, including diarrhea[95]. These early experiences may lead to negative associations with food, contributing to behavioral disorders like food refusal or selective eating, both of which can cause irregular bowel habits[96,97]. Furthermore, children who experience pressure to eat or are overfed may develop stress-related digestive issues, linking meal-related anxiety to functional diarrhea and increasing the risk of emotional disorders over time[97]. Functional diarrhea often coexists with psychological conditions such as anxiety, depression, and ADHD. Stressful situations like school exams or social interactions can trigger frequent bouts of diarrhea in children with anxiety. Their inability to regulate stress responses heightens the likelihood of developing chronic anxiety disorders linked to GI symptoms[98,99]. In children with ADHD, impulsivity and difficulty following routines may lead to irregular eating patterns, exacerbating diarrhea. These behavioral challenges increase emotional dysregulation, further complicating the management of functional diarrhea and increasing susceptibility to anxiety and depression[99]. Changes in appetite and food intake associated with depression can alter GI motility, leading to diarrhea. Emotional disturbances in depression disrupt the brain-gut axis, making children more vulnerable to GI complaints[100].

Visceral hypersensitivity is a common feature of functional diarrhea, where children experience heightened sensitivity to normal gut processes[30]. Emotional distress exacerbates this hypersensitivity, leading to discomfort or pain during digestion. This psychosomatic response manifests as physical symptoms, where emotional stress, particularly anxiety, triggers GI complaints like cramping or diarrhea, even in the absence of an organic cause. Over time, this can lead to somatic symptom disorder, where emotional distress is primarily expressed through physical symptoms[101,102]. Trauma and adverse childhood experiences, including abuse, neglect, or significant loss, increase the risk of FGIDs, including functional diarrhea[103]. Early trauma disrupts emotional regulation, leading to chronic stress that affects GI function through the brain-gut axis. Children with trauma histories often develop somatization, where emotional distress manifests as GI symptoms, increasing their susceptibility to PTSD and other psychological disorders[104,105]. This dysregulation in the autonomic nervous system can lead to chronic diarrhea, making early psychological intervention essential for effective management.

Social pressures, such as academic demands, peer relationships, and social media exposure, also contribute to functional diarrhea. Heightened stress from social situations or fear of embarrassment may lead to coping mechanisms like overeating or food avoidance, worsening GI symptoms[106]. For example, children facing social anxiety may develop functional diarrhea in response to stress related to social interactions, increasing their risk of social anxiety disorder[65,107]. These stress-induced GI symptoms can create a cycle of emotional distress and physical complaints, further complicating psychological well-being.

Cyclic vomiting syndrome: Cyclic vomiting syndrome (CVS), a FGID, is characterized by recurrent, intense episodes of vomiting lasting hours to days, with symptom-free intervals in between[108]. While the precise cause remains unclear, the psychological etiology of CVS in infants and children is closely linked to emotional and psychological factors. Emotional stress, anxiety, family dynamics, and early-life experiences play significant roles in the manifestation of CVS, and these factors are closely tied to the development of psychological disorders such as anxiety, depression, and somatic symptom disorder[109,110]. Psychosocial stress is a critical trigger for cyclic vomiting episodes in children, primarily mediated through the brain-gut axis, a bidirectional communication network between the CNS and the GI tract[17,109]. Stressful life events, such as school pressure, social anxieties, or family conflicts, can disrupt GI motility, secretion, and sensation, leading to vomiting episodes. In children with underlying anxiety disorders, this heightened sensitivity can exacerbate symptoms, contributing to anticipatory anxiety, where the fear of future vomiting episodes becomes a psychological trigger, reinforcing both anxiety and vomiting[110]. Over time, this feedback loop can increase the risk of developing generalized anxiety disorder (GAD) or panic disorder, particularly in children prone to heightened stress responses.

Family dynamics play a pivotal role in the psychological etiology of CVS. Children raised in environments with high stress, overprotection, or emotional instability are more susceptible to stress-related GI disorders like CVS[111]. Parental anxiety, particularly maternal anxiety, can exacerbate the severity of CVS episodes by reinforcing the child's symptoms. For instance, when parents focus excessively on their child’s health during episodes, the child may associate vomiting with receiving attention, creating a behavioral feedback loop that perpetuates the condition[112]. Conversely, children from high-conflict or emotionally neglectful households may somatize their distress, using vomiting as an unconscious expression of emotional turmoil, which can contribute to the development of somatic symptom disorder[113].

Early-life stressors, such as family separation, loss of a loved one, or exposure to violence, can predispose children to CVS by disrupting emotional regulation and increasing chronic stress[114]. This chronic stress sensitizes the brain-gut axis, making the GI system more reactive to emotional disturbances. Children with trauma histories often exhibit heightened autonomic responses, such as increased sympathetic nervous system activity, which can trigger nausea and vomiting under emotional strain[115]. This can lead to somatization, where emotional distress manifests as physical symptoms and increases the risk of developing PTSD or anxiety disorders[116].

CVS is often associated with psychological comorbidities, particularly anxiety and depression[109]. Children with anxiety disorders, including GAD and panic disorder, are more likely to experience anticipatory nausea and vomiting during stressful situations, creating a cycle of anxiety and physical symptoms that exacerbates CVS[109,117]. Depression can also contribute to CVS by manifesting physical symptoms like nausea and vomiting, reflecting emotional turmoil. Depressive symptoms such as changes in appetite, sleep disturbances, and reduced coping abilities can worsen CVS episodes and increase susceptibility to mood disorders[118]. Although the connection is less direct, children with ADHD may exhibit irregular eating and sleeping patterns, impairing their ability to regulate stress and triggering vomiting episodes. Impulsivity and emotional dysregulation in ADHD further complicate CVS management and increase the risk of developing comorbid behavioral disorders[119]. Children with CVS often exhibit visceral hypersensitivity, where heightened sensitivity to normal GI sensations increases susceptibility to nausea and vomiting[30,120]. Emotional stress amplifies this sensitivity, making even mild stimuli, such as anxiety or excitement, trigger severe vomiting episodes. The disturbed brain-gut axis is an important factor in visceral hypersensitivity, linking psychological factors to GI symptoms and increasing the likelihood of developing anxiety-related disorders over time[121].

Social and environmental factors, such as academic pressure, peer relationships, and exposure to bullying, significantly contribute to CVS by heightening emotional stress[122,123]. Children under academic or social pressure may experience stress-induced vomiting, particularly during high-stress periods like exams or public performances. Additionally, the rise of social media and exposure to unrealistic societal expectations can exacerbate anxiety, leading to CVS episodes. Negative self-comparisons and fear of judgment increase emotional distress, making children more vulnerable to social anxiety disorder and somatic symptom expression through vomiting[124,125]. Children with CVS may develop conditioned responses to certain emotional or environmental triggers. For example, if vomiting episodes are consistently linked to school-related stress, the child may begin to associate school with vomiting, even in the absence of immediate stress[108]. This classical conditioning can make children more prone to future vomiting episodes in similar situations. Behavioral responses, such as avoiding foods, environments, or activities associated with past episodes, reinforce the cycle of vomiting and anxiety, increasing the likelihood of avoidant behaviors and heightened anticipatory anxiety[126].

IBS: IBS, a FGID, is characterized by chronic or recurrent abdominal pain and changes in bowel habits, including diarrhea, constipation, or both[127]. The psychological etiology of IBS in infants and children is multifactorial, involving psychosocial stress, family dynamics, emotional regulation, early-life experiences, and comorbid psychological conditions such as anxiety and depression[128]. These psychological mechanisms not only influence the onset and persistence of IBS symptoms but are also closely linked to the development of psychological disorders, creating a bidirectional relationship between GI distress and mental health[129,130]. Psychosocial stress is a key factor in triggering and exacerbating IBS symptoms in children. Stress from academic pressure, family conflicts, or social challenges activates the HPA axis, releasing cortisol and other stress hormones that impact the brain-gut axis[101]. Dysregulation of this axis can lead to altered GI motility, heightened sensitivity, and immune dysfunction—all hallmark features of IBS[129]. Chronic exposure to stress can result in the development of anxiety disorders such as GAD or social anxiety disorder, as children begin to associate stress with GI discomfort. This association creates a cycle where anxiety worsens IBS symptoms, and IBS symptoms, in turn, intensify anxiety, leading to persistent psychological distress[130].

Family dynamics play a significant role in the psychological development of IBS. Children raised in high-stress environments with parental anxiety, conflict, or overprotection are more prone to developing IBS symptoms[131]. Parental anxiety, particularly maternal anxiety, can be transmitted to children through emotional contagion, reinforcing their focus on GI discomfort. This excessive focus can increase the risk of somatic symptom disorder, where emotional distress is expressed through physical symptoms like abdominal pain or altered bowel habits[132]. Conversely, children experiencing emotional neglect or inconsistent caregiving may somatize their unmet emotional needs, heightening their vulnerability to depression and mood disorders and further exacerbating IBS[101]. Early-life stressors, such as family disruptions, exposure to violence, or significant losses, are strongly associated with IBS. Children who experience early trauma often exhibit heightened stress reactivity, leading to visceral hypersensitivity - a heightened sensitivity of the GI nerves to normal stimuli[133,134]. This hypersensitivity can manifest as abdominal pain or discomfort in response to digestion, contributing to IBS symptoms. Chronic trauma can also lead to PTSD, with GI symptoms serving as a somatic expression of unresolved emotional distress. Long-term dysregulation of the brain-gut axis due to trauma increases susceptibility to IBS and related psychological disorders[135].

IBS is commonly associated with psychological comorbidities, particularly anxiety and depression, which exacerbate and are exacerbated by IBS symptoms. Children with anxiety disorders experience heightened stress responses that disrupt gut motility and increase abdominal pain during stressful situations[136]. Anticipatory anxiety about IBS symptoms can lead to further GI distress, establishing a cycle of anxiety and physical discomfort and increasing the likelihood of developing GAD or panic disorder[101]. Depression, while less common, can manifest as physical symptoms such as changes in appetite, sleep disturbances, and GI discomfort. Depressed children may have reduced pain tolerance, making normal gut sensations feel more painful, which worsens IBS symptoms and increases susceptibility to mood disorders[65,132]. Visceral hypersensitivity is a defining characteristic of IBS, particularly in children experiencing psychological distress. Emotional stress and anxiety heighten this sensitivity, leading to an exaggerated pain response to normal gut stimuli[137]. Children who struggle with emotional regulation often experience more severe IBS symptoms during periods of emotional upheaval. The dysregulated brain-gut axis in these children not only intensifies GI symptoms but also increases their risk of developing emotional disorders like anxiety and depression[138,139].

Social and environmental factors, such as school stress, peer relationships, and social media exposure, significantly influence the psychological development of IBS in children. Academic pressure and social challenges can manifest as GI symptoms, contributing to the development of social anxiety disorder[140,141]. Additionally, exposure to unrealistic societal expectations on social media can heighten anxiety and stress, exacerbating IBS symptoms in children prone to emotional sensitivity[142]. The combination of societal pressures and pre-existing psychological vulnerabilities increases the risk of somatic symptom manifestation through IBS. Conditioning plays a crucial role in the psychological etiology of IBS. Children may develop conditioned responses to specific emotional or environmental triggers, such as associating school or social events with GI distress[143]. These conditioned responses can perpetuate IBS symptoms, as the child’s anxiety about experiencing symptoms reinforces abdominal pain and altered bowel habits. Avoidant behaviors, such as avoiding certain foods, activities, or environments, can further entrench anxiety, making IBS more difficult to manage and increasing the likelihood of persistent psychological distress[144,145].

FAP: FAP is a type of FGID in infants and children characterized by chronic or recurrent abdominal pain without an identifiable structural or biochemical cause[146]. The psychological etiology of FAP involves a multifactorial interaction between emotional stress, family dynamics, early-life experiences, coping mechanisms, and psychosocial comorbidities such as anxiety and depression. These psychological mechanisms not only contribute to the onset and persistence of FAP but are also closely linked to the development of psychological disorders, creating a bidirectional relationship between abdominal pain and mental health[147,148]. Psychosocial stress is central to the development and exacerbation of FAP. Stressors such as school pressure, bullying, social challenges, or family conflicts activate the brain-gut axis, a bidirectional communication pathway between the brain and the GI system[148]. Emotional stress disrupts gut motility, increases sensitivity, and alters pain perception, leading to heightened visceral sensitivity - a hallmark feature of FAP. This condition, where normal GI stimuli are perceived as painful, is exacerbated by stress and is closely associated with anxiety disorders. Children with high-stress levels may develop GAD or social anxiety disorder, both of which can worsen FAP symptoms, creating a cycle where anxiety perpetuates abdominal pain and vice versa[149,150].

Family dynamics significantly influence the psychological development of FAP. High-stress family environments characterized by parental conflict, overprotection, or anxiety increase a child's risk of developing FAP[150]. Parental anxiety, especially maternal anxiety, can be transferred to the child through emotional contagion, reinforcing the child’s focus on their pain and increasing the risk of somatic symptom disorder, where emotional distress is expressed through physical symptoms[151]. Conversely, emotionally neglectful family environments can lead to unmet emotional needs, prompting children to somatize their distress as abdominal pain. This lack of emotional security increases susceptibility to depression and mood disorders, further exacerbating FAP symptoms[152]. Early-life trauma, including parental divorce, loss of a loved one, or exposure to violence, is strongly associated with FAP[153]. Traumatic experiences can disrupt emotional regulation and lead to maladaptive coping mechanisms, such as somatization, where psychological distress manifests as physical symptoms. The brain-gut axis mediates the link between trauma and FAP, with long-term changes in communication between the brain and the gut resulting in increased pain sensitivity and altered GI functioning. This heightened sensitivity often contributes to the development of PTSD and anxiety disorders, making children with trauma histories more vulnerable to severe FAP episodes[154,155].

Children with FAP often present with psychological comorbidities, particularly anxiety and depression. Anxious children tend to exhibit heightened stress reactivity, leading to increased abdominal pain perception during stressful situations such as attending school or social events[136,149]. This heightened sensitivity to stress can evolve into chronic anxiety disorders, perpetuating the cycle of abdominal pain and psychological distress. Depression in children can lower pain thresholds, making them more sensitive to abdominal discomfort. Depressive symptoms such as changes in appetite, fatigue, and sleep disturbances further exacerbate FAP by disrupting GI function and increasing the likelihood of mood disorders[150,156]. The way children cope with emotional stress significantly influences the psychological etiology of FAP. Children who lack effective coping mechanisms often internalize stress, expressing it through somatic symptoms like abdominal pain[157]. Somatization is common in children with poor emotional regulation or limited social support, where emotional distress manifests as physical symptoms without an identifiable medical cause[158]. This can lead to the development of somatic symptom disorder, where the child's fixation on physical symptoms reinforces the pain cycle and increases susceptibility to anxiety and depression[159].

Social stressors, such as difficulties in making friends, bullying, or academic pressure, contribute significantly to FAP[160]. These stressors heighten anxiety levels, which disrupt the brain-gut axis and increase GI pain sensitivity. In addition, exposure to social media and societal expectations can exacerbate stress, leading to social anxiety disorder and an increased frequency of FAP episodes. Children who feel overwhelmed by peer comparisons or societal standards may internalize this stress, further reinforcing the cycle of abdominal pain and emotional distress[161,162]. Maladaptive behavioral responses play a crucial role in perpetuating FAP. Children may avoid activities or situations associated with pain, such as school or specific foods, reinforcing their focus on abdominal pain and increasing anxiety[163]. Conditioned pain perception occurs when repeated abdominal pain episodes in response to stress create automatic responses to certain triggers, even in the absence of immediate stress[164]. These conditioned and avoidant behaviors contribute to the persistence of FAP and increase the risk of developing comorbid psychological disorders like anxiety and depression.

Abdominal migraine: Abdominal migraine (AM) is an FGID in children that is characterized by recurrent episodes of severe central abdominal pain, often accompanied by nausea, vomiting, and pallor[165]. Despite its classification as a GI disorder, the psychological etiology of AM involves complex interactions between stress, emotional regulation, family dynamics, and comorbid psychological conditions, such as anxiety and depression[166]. Understanding the psychological factors behind AM is crucial, as they significantly influence the onset, severity, and recurrence of this condition in infants and children.

Psychosocial stress plays a significant role in the development and exacerbation of AM in children. The brain-gut axis, a bidirectional communication system between the CNS and the GI tract, is highly sensitive to emotional stress[167]. Stressful situations, whether at home, school or in social environments, can trigger episodes of AM by affecting the neural pathways that modulate pain perception and gut motility. Children with AM may exhibit heightened sensitivity to stress, leading to disruptions in the autonomic nervous system[168]. This can result in altered gut motility, vasodilation, and visceral hypersensitivity, which are common disorder features. Episodes of AM are often triggered or worsened by emotional stressors, such as school exams, family conflicts, or social pressures. The impact of stress on the brain-gut axis is mediated by neuropeptides and stress hormones, such as cortisol, which can exacerbate abdominal pain and other symptoms[169].

Children with AM often have difficulties with emotional regulation, which refers to their ability to manage and respond to emotional experiences in a healthy manner[170]. Those who struggle to cope with negative emotions, such as anxiety, frustration, or sadness, are more likely to experience AM episodes. Emotional dysregulation can lead to somatization, a process in which psychological stress is expressed through physical symptoms, including abdominal pain. These children may have an exaggerated stress response, where even minor emotional triggers can lead to significant physiological changes, such as vasoconstriction and GI disturbances[171]. This heightened stress response can make children more vulnerable to experiencing the pain and discomfort associated with AM. Emotional dysregulation also perpetuates the disorder, as children may become more focused on their pain during times of emotional distress, leading to a vicious cycle of pain and stress[149].

Family dynamics play an essential role in the psychological etiology of AM. Children who grow up in stressful or emotionally unstable family environments may be more prone to developing AM. Parental overprotection, anxiety, or conflict can significantly influence a child’s emotional state and stress levels. In particular, parental anxiety can be projected onto the child, leading the child to internalize stress and focus on their physical symptoms[172]. Additionally, some children with AM may come from families where emotional distress is frequently expressed through physical complaints, creating a model for the child to follow. Suppose a parent or caregiver frequently complains of headaches, stomachaches, or other somatic symptoms during times of stress[170]. In that case, the child may learn to express their stress similarly, leading to the development of AM. Conversely, children who experience emotional neglect or a lack of support at home may develop AM as a response to unmet emotional needs. These children may feel isolated or insecure, leading to emotional dysregulation and somatization of stress. The unpredictable nature of AM episodes can further strain family relationships, creating a feedback loop that perpetuates the child’s pain and stress[168].

Early life stressors, such as trauma or adverse childhood experiences, have a profound impact on the development of AM. Children who experience early life trauma, such as parental divorce, the death of a loved one, or exposure to abuse, are more likely to develop FGIDs, including AM[173]. These traumatic experiences can alter the brain’s stress-response system, particularly the HPA axis, which regulates stress hormones like cortisol. Dysregulation of the HPA axis can lead to increased sensitivity to stress and pain, both of which are hallmark features of AM. Trauma-induced changes in the brain-gut axis can result in long-term alterations in how the body processes pain and stress[35]. This may explain why children with a history of trauma or chronic stress are more likely to experience recurrent episodes of abdominal pain and other migraine symptoms. In some cases, AM may serve as a somatic manifestation of unresolved emotional trauma, where the body expresses psychological distress through physical symptoms[174].

Children with AM frequently have comorbid psychological conditions, most commonly anxiety and depression. These psychological disorders are known to exacerbate AM symptoms and increase the frequency and severity of pain episodes[175]. Anxiety, in particular, is closely associated with AM, as anxious children tend to have a heightened sensitivity to physical discomfort and stress[176]. This can lead to an overactive stress-response system, which triggers episodes of abdominal pain, nausea, and vomiting typical of AM. Depression can also play a role in the development and persistence of AM. Depressed children may experience changes in their perception of pain, making them more susceptible to abdominal discomfort[177]. Additionally, depression often leads to symptoms such as fatigue, changes in appetite, and sleep disturbances, all of which can worsen AM episodes. The emotional withdrawal and feelings of hopelessness associated with depression can further exacerbate the child’s physical symptoms, creating a cycle of pain and emotional distress[178].

Children’s coping mechanisms significantly impact the psychological etiology of AM. Those who lack effective ways to cope with stress, anxiety, or negative emotions may be more likely to somatize their emotional distress[116]. Somatization occurs when psychological stress is expressed as physical symptoms, and in the case of AM, this often manifests as recurrent episodes of abdominal pain. Children who struggle with emotional regulation may focus on their physical symptoms as a way to express their emotional turmoil[179]. This can lead to a preoccupation with pain, where the child becomes hyper-focused on their abdominal discomfort, exacerbating the frequency and severity of AM episodes. This somatization process is often reinforced by parental attention and concern, which can unintentionally perpetuate the child’s pain symptoms[180].

Social and environmental factors, such as school pressure, peer relationships, and social media influence, also contribute to the psychological etiology of AM[181]. Children who experience stress in these areas are more likely to develop FGIDs. For example, a child who feels overwhelmed by academic pressure or struggles with peer relationships may experience heightened stress levels, which can trigger episodes of AM. Additionally, exposure to social media and societal expectations can increase stress and anxiety in children, particularly if they feel pressured to meet unrealistic standards of success or appearance. This social stress can further exacerbate AM symptoms, leading to more frequent and severe episodes of abdominal pain and associated symptoms[182]. Table 2 summarizes the psychological mechanisms underlying various FGIDs.

Table 2 The psychological mechanisms underlying various functional gastrointestinal disorders.

FGID	Psychological mechanisms
Infant colic	Psychosocial stress: High parental stress and anxiety may contribute to infant colic through alterations in caregiving responses and infant stress reactivity
	Parent-infant interaction: Stressful caregiving environments and ineffective soothing strategies may exacerbate colic symptoms
	Family dynamics: Parental conflict or lack of support can increase stress levels, impacting infant behavior and gastrointestinal symptoms
Functional constipation	Psychosocial stress: Stress from social or academic pressures can affect bowel habits and lead to constipation
	Emotional regulation: Difficulty managing emotions may result in withholding behavior, contributing to constipation
	Family dynamics: Overcontrolling or punitive parenting styles regarding toilet training may increase constipation risk
	Coping mechanisms: Ineffective coping strategies or anxiety about bowel movements can exacerbate symptoms
GER	Psychosocial stress: Stress can affect gastrointestinal motility and increase acid reflux symptoms
	Emotional regulation: Stress or anxiety may exacerbate ger symptoms by increasing gastric acid production or sensitivity
	Family dynamics: High-stress family environments may influence feeding practices and exacerbate reflux symptoms
Diarrhea	Psychosocial stress: Stress and anxiety can affect gut motility and contribute to episodes of diarrhea
	Emotional regulation: Difficulty managing stress can lead to gastrointestinal disturbances, including diarrhea
	Family dynamics: Family stressors or dysfunctional family environments may impact bowel habits and exacerbate diarrhea
IBS	Psychosocial stress: Stress and anxiety play a significant role in IBS, influencing symptoms through the brain-gut axis
	Emotional regulation: Difficulty managing emotions can lead to altered gut motility and heightened sensitivity
	Family dynamics: Dysfunctional family environments or high levels of family stress may exacerbate IBS symptoms.
	Coping mechanisms: Ineffective coping strategies may lead to somatization of stress
Cyclic vomiting syndrome	Psychosocial stress: Stressful events or emotional distress can trigger episodes of cyclic vomiting
	Emotional regulation: Poor emotional regulation may contribute to the severity and frequency of vomiting episodes
	Family dynamics: Stressful family environments or parental anxiety can impact the frequency and intensity of episodes
Dysfunctional abdominal pain	Psychosocial stress: Emotional stress and psychosocial factors can contribute to chronic abdominal pain through the brain-gut axis
	Emotional regulation: Ineffective emotional regulation can lead to persistent pain perception
	Family dynamics: Family stress and conflicts may exacerbate symptoms by affecting the child’s emotional state
	Coping mechanisms: Poor coping strategies and somatization of stress may perpetuate pain symptoms
Abdominal migraine	Psychosocial stress: Stress can trigger episodes of abdominal migraine by affecting the brain-gut axis and stress-response systems
	Emotional regulation: Poor emotional regulation can lead to somatization of stress and exacerbate symptoms
	Family dynamics: Parental stress or emotional instability can impact the child’s susceptibility to abdominal migraines
	Early life stressors: Trauma or adverse experiences can alter stress-response systems, contributing to abdominal migraine
	Coping mechanisms: Ineffective coping strategies may exacerbate the frequency and severity of episodes

This table provides an overview of the psychological mechanisms associated with each FGID, focusing on factors such as psychosocial stress, emotional regulation, family dynamics, and coping mechanisms. IBS: Irritable bowel syndrome; FGID: Functional gastrointestinal disorder; GER: Gastroesophageal reflux.

Short-term psychological impacts of FGIDs in infants and children

While FGIDs are primarily characterized by physical symptoms, they also have profound psychological impacts on both the affected children and their families. The short-term psychological effects of FGIDs can manifest in various ways, often intertwining with the physical symptoms to create a complex clinical picture[183].

Infant colic: Infant colic is one of the most common and distressing FGIDs in early childhood, typically manifesting within the first few weeks of life and often peaking around six weeks of age[184]. Characterized by episodes of intense, inconsolable crying in an otherwise healthy and well-fed infant, colic has long been a source of frustration and anxiety for parents. While colic is traditionally seen as a benign and self-limiting condition that resolves by three to four months of age, its short-term psychological impacts can be profound, affecting not only the infant but also the parents and family dynamics[185].

The immediate psychological impact of colic is the significant distress and discomfort the infant experiences. Colic episodes, characterized by prolonged periods of crying and irritability, can occur without an identifiable cause, leaving both the infant and the caregivers helpless[186]. While the exact etiology of colic remains unclear, the associated discomfort may stem from GI pain, overstimulation, or an immature nervous system. During colic episodes, infants may exhibit signs of heightened stress, such as increased heart rate, elevated cortisol levels, and physical tension[187]. This heightened stress response, if recurrent, could potentially affect the infant's developing stress regulation systems. Although this is still a subject of ongoing research, the persistent discomfort may disrupt the infant's ability to self-soothe and regulate emotions in the short term. Colic often interferes with an infant's sleep, leading to fragmented or insufficient sleep. Sleep disturbances can exacerbate the infant's irritability and distress, creating a cycle where poor sleep contributes to colic episodes, and colic episodes disrupt sleep[188]. Sleep is critical for healthy brain development, and disruptions in sleep patterns may have short-term effects on the infant’s emotional regulation and overall well-being[189].

One of infant colic's most significant short-term psychological impacts is its effect on the parent-infant bond. The inconsolable crying that characterizes colic can lead to feelings of frustration, helplessness, and inadequacy in parents, particularly in first-time parents who may already be anxious about their caregiving abilities. The intense and unpredictable nature of colic episodes can lead to heightened stress and anxiety in parents. They may feel overwhelmed by the challenge of soothing their infant, leading to doubts about their parenting abilities[190]. This stress can interfere with the natural bonding process between parent and child, as parents may feel emotionally drained or distant due to the constant demands of caring for a colicky infant. The stress associated with managing an infant with colic can also increase the risk of postpartum depression, particularly in mothers[191]. The relentless crying and lack of effective soothing strategies can contribute to feelings of hopelessness and despair, which are key features of postpartum depression. This, in turn, can further affect the quality of the parent-infant relationship, as depressed parents may struggle to engage emotionally with their infant[192]. The early months of life are critical for developing a secure attachment between the infant and their caregivers. Colic can strain this attachment process, as parents may become frustrated or resentful towards the infant due to the constant crying. While most parents navigate this challenging period without long-term consequences, some may experience difficulties in forming a secure attachment, which could have short-term implications for the infant’s emotional and social development[193].

Infant colic does not only affect the infant and primary caregiver but can also have broader implications for the entire family dynamic. The strain of dealing with a colicky infant can lead to increased tension and conflict within the family, particularly between parents[184]. The stress of managing colic can strain the relationship between partners, particularly if they disagree on caregiving strategies or if one partner feels unsupported by the other. This can lead to increased arguments and reduced overall marital satisfaction during this already challenging period. If there are older siblings in the family, they may also be affected by the disruptions caused by a colicky infant[194]. Siblings may feel neglected due to the significant attention and care the infant requires, leading to feelings of jealousy or resentment. The constant crying can also create a stressful home environment for other children, potentially affecting their emotional well-being[184].

Infants with colic may develop specific behavioral patterns in response to their discomfort and how their caregivers respond to their needs. These patterns can have short-term psychological effects that may influence their subsequent behavior and interactions[195]. Infants who experience colic may develop a heightened sensitivity to discomfort or environmental stimuli, leading to increased irritability and crying even outside of colic episodes. This heightened reactivity may be a short-term coping mechanism, but it can also make caregiving more challenging and stressful for parents[196]. Parents may rely on specific soothing mechanisms to manage the crying associated with colic, such as rocking, pacifiers, or car rides. While these strategies can be effective in the short term, they may lead to a dependency on external soothing, making it more difficult for the infant to learn self-soothing skills[45]. This can have short-term implications for infants' ability to regulate their emotions and settle themselves, particularly at bedtime.

The constant distress associated with colic can affect an infant's early social interactions with their caregivers and others. During the first few months of life, infants begin to develop foundational social skills, such as eye contact, smiling, and cooing, which are essential for building relationships and communication skills[197]. Colic episodes can lead to periods of reduced social engagement, where the infant is too distressed to interact meaningfully with caregivers. This can limit opportunities for positive social interactions and bonding during a critical development period[198]. The crying associated with colic may overshadow other forms of communication, such as cooing or babbling. Parents may find it challenging to engage in typical back-and-forth interactions with their infant, which are essential for language development and social communication. In the short term, this may delay the development of early communication skills[199]. Figure 2 summarizes the short-term psychological impact of infant colic on the baby and the family.

Figure 2 The short-term psychologic impact of infant colic on the baby and the family.

FC: FC is one of the most common FGIDs in infants and children. While the physical symptoms - such as infrequent or painful bowel movements - are the primary concern, the short-term psychological impacts of FC can be profound and multifaceted. These psychological impacts affect the child and the family dynamics and interactions[200].

Children with FC often experience significant emotional distress due to the discomfort and pain associated with bowel movements. This can manifest in various ways. Due to repeated painful bowel movements, children may develop a fear of defecating, causing them to withhold stool, which exacerbates the constipation[57]. This creates a vicious cycle of anxiety and fear. Older children, especially those who have begun attending school, may feel embarrassed by their condition. Accidents (fecal incontinence due to overflow or encopresis) can be humiliating, leading to a loss of self-esteem and confidence[201]. Constant discomfort from bloating and abdominal pain can lead to irritability and frustration in younger children. This may result in mood swings, temper tantrums, and difficulty in emotional regulation. The stress of the condition may make some children anxious about separating from their parents, especially when going to school or attending social activities, where accidents might occur[202].

Children with FC may develop behavioral coping mechanisms that have short-term psychological consequences. Some children may begin to avoid using the toilet entirely due to the fear of painful bowel movements. This avoidance exacerbates the condition, leading to a cyclical pattern of constipation and increasing psychological stress[61]. Older children, particularly those aware of their condition, may withdraw from social activities, such as playdates, school events, or sleepovers, out of fear of embarrassment. This avoidance can lead to feelings of isolation and loneliness, affecting their social development and peer relationships[203]. Infants and young children with FC may become more dependent on their parents for comfort, reassurance, and assistance with bathroom-related activities. This increased dependency can foster anxiety in situations where the child is separated from their parents, such as during school or daycare[204].

For school-aged children, FC can lead to significant short-term psychological impacts related to their school experience. Children with FC may miss school due to abdominal pain, discomfort, or anxiety about bowel movements[54]. Frequent absenteeism can affect their academic performance and increase feelings of stress and guilt about falling behind in schoolwork. Children who experience accidents at school due to fecal incontinence may be subject to teasing or bullying from peers. This can lead to feelings of social isolation, embarrassment, and a reluctance to participate in group activities, which may have long-term effects on social development[205]. The physical discomfort associated with constipation, such as bloating and cramping, can make it difficult for children to focus on schoolwork. This can lead to short-term academic challenges, including poor performance or difficulty maintaining classroom attention[206].

FC is often managed through dietary changes, including increasing fiber and fluid intake. These dietary changes can have psychological effects, especially if the child is resistant to these changes. Children may resist new foods or dietary restrictions, especially if they are picky eaters or dislike high-fiber foods. The resulting tension around mealtimes can create anxiety for both the child and the parents[207]. For some children, constipation may cause them to develop negative associations with food, particularly if certain foods are perceived as causing discomfort. This may lead to disordered eating patterns, including food aversions or restrictive eating. Some children may develop a pattern of emotional eating, where they seek comfort from their psychological distress by overeating or consuming unhealthy foods. This behavior can worsen constipation, creating a negative feedback loop[208]. In the short term, FC can affect a child's self-image and self-worth. Children who experience constipation, especially those with incontinence, may develop a negative self-image. They may feel “different” from their peers, which can affect their confidence and self-esteem. Some children may become preoccupied with their abdominal discomfort or bloating, which may affect how they perceive their bodies. They may feel uncomfortable or embarrassed about their appearance, especially if their symptoms are noticeable to others[57].

Parents of children with FC often experience significant psychological strain, which can have short-term effects on family dynamics. Parents often become anxious and hyper-focused on their child's bowel habits, constantly worrying about whether the child has had a bowel movement or is experiencing pain[209]. This anxiety may lead to overprotectiveness or excessive monitoring of the child's behavior. When attempts to manage the child's condition (e.g., changes in diet, hydration, or medication) do not yield immediate results, parents can feel helpless. The chronic nature of the condition, coupled with the child’s resistance to using the toilet, can create feelings of frustration[210]. Some parents may feel guilty, believing they are responsible for their child’s constipation. This can be particularly distressing for parents who feel they may have missed earlier signs of the condition or have inadvertently contributed to the issue by neglecting dietary or lifestyle habits[209]. The constant vigilance and effort required to manage a child’s constipation can lead to emotional exhaustion and parental burnout, especially when combined with other responsibilities. This may result in a decline in the quality of parenting and reduced emotional availability for the child[211]. Figure 3 summarizes the interconnected nature of the psychological impacts of FC on both the child and the family. The specific effects may vary depending on the child's age, severity of symptoms, and family dynamics.

Figure 3 The psychological impacts of functional constipation on both the child and the family. This figure provides a visual representation of the interconnected nature of functional constipation's psychological impacts on both the child and the family. The specific effects may vary depending on the child's age, severity of symptoms, and family dynamics.

Functional GER: Functional GER is a common FGID. GER is a condition in infants and children characterized by the backflow of stomach contents into the esophagus without any identifiable underlying pathological cause. While GER primarily manifests through physical symptoms like regurgitation, vomiting, and discomfort, it also has notable psychological impacts, particularly in the short term[212]. The psychological repercussions of GER in infants and children can affect both the child and the caregiver, influencing emotional well-being, behavior, and overall mental health. Infants with GER often experience significant emotional distress due to frequent discomfort and pain from acid reflux[213]. This discomfort can manifest as excessive crying, irritability, and difficulty soothing. Infants may become fussy during and after feedings, leading to a negative cycle where the infant associates feeding with discomfort. This ongoing emotional stress can hinder their ability to engage in typical soothing behaviors and may disrupt their emotional development. These behavioral responses are typically due to pain perception, as infants cannot verbalize their discomfort, leading to high levels of irritability[214].

GER can lead to sleep disturbances in infants and children, a factor that contributes to short-term psychological effects. The discomfort caused by reflux is often exacerbated when lying down, causing frequent waking, difficulty falling asleep, or restless sleep. Both acid and non-acid GER cause equal degrees of sleep disturbances and arousal in the affected infants and children. Sleep disruptions negatively impact the emotional regulation of children[215]. Infants and toddlers with GER who experience sleep fragmentation may become more irritable and prone to mood fluctuations during the day. This lack of restorative sleep can contribute to daytime behavioral problems, including increased fussiness and reduced attention span, further complicating parent-child interactions. Children with GER often develop feeding aversions due to the association of feeding with discomfort[216]. Infants may become distressed during feedings, refuse to eat, or eat less than expected. This can create anxiety surrounding feeding times, both for the child and the caregiver. The child may become apprehensive about feeding, leading to poor weight gain and nutritional deficits[217]. Feeding aversion also has broader emotional consequences, such as increasing the child’s general anxiety levels and reducing their sense of security during meals. Caregivers may also become anxious about ensuring adequate nutrition, further adding stress to feeding sessions[218].

Children with GER may become more socially withdrawn due to discomfort or pain, especially if their reflux episodes are frequent and severe. In older children, this can result in them avoiding social situations, such as eating with peers, leading to feelings of isolation[219]. Social withdrawal can have negative impacts on their psychological development, including impairments in social skills and self-esteem. For infants and younger children, the irritability and discomfort from GER can lead to decreased engagement with their caregivers or other people, reducing opportunities for positive social interactions[220]. In the short term, GER may affect an infant's or child's developmental milestones. Irritability, sleep disturbances, and feeding difficulties can impede normal developmental processes for infants. Lack of proper nutrition due to feeding aversion can also result in delayed physical growth and cognitive development[221]. Discomfort caused by GER may also reduce the infant’s motivation to engage in physical activities, like tummy time or crawling, which are essential for motor development. The discomfort caused by GER can also lead to behavioral issues in children. Infants and toddlers with untreated or poorly managed GER may exhibit temper tantrums, restlessness, or clingy behavior due to the discomfort they feel[222]. Older children may become more prone to mood swings, frustration, or oppositional behavior as they struggle to cope with the physical discomfort caused by reflux. The behavioral manifestations are often linked to their inability to articulate the discomfort and their attempt to seek relief[223].

In older children, the psychological effects of GER can manifest as somatization, where emotional stress is expressed through physical symptoms. A child experiencing recurrent GER episodes may develop a heightened sensitivity to bodily sensations, perceiving normal digestive functions as painful or distressing[224]. This can lead to increased complaints of stomach pain or discomfort, even without reflux episodes. The anticipation of discomfort can increase anxiety, potentially worsening the symptoms and leading to more frequent GER episodes. GER symptoms may interfere with cognitive function and academic performance in older children[78]. Children who experience frequent discomfort from GER, especially at night, may struggle to concentrate at school due to fatigue or distraction from pain. Sleep disturbances and anxiety caused by GER can negatively affect their attention span, memory retention, and overall cognitive functioning. These short-term academic issues can also exacerbate psychological stress, as children may feel overwhelmed or anxious about their inability to keep up with schoolwork[225].

GER can place a substantial psychological burden on caregivers, especially parents. The infant's frequent crying, irritability, and discomfort can cause parents to feel helpless, anxious, and frustrated[226]. Parents may constantly worry about whether their child is getting enough nutrition or if there is an underlying serious condition leading to increased stress levels. The emotional toll on caregivers can manifest as anxiety, sleep deprivation, and, in some cases, depression[213]. The constant worry and emotional strain can also disrupt the parent-child bond, as parents may become hypervigilant about the child’s symptoms, leading to a negative feedback loop of stress and anxiety within the household[227]. The stress of managing GER in infants and children can strain the caregiver-child relationship. Parents or caregivers may become frustrated or overwhelmed by the child’s constant crying, feeding difficulties, and sleep disturbances. In extreme cases, the frustration can escalate into feelings of inadequacy or resentment, especially if caregivers feel that they are unable to soothe or comfort the child. This strain can disrupt bonding and attachment processes, which are crucial in the early developmental stages of infancy and childhood[228]. Figure 4 summarizes the short-term psychological impacts of GER in infants and children.

Figure 4 Short-term psychological impacts of functional gastroesophageal reflux in infants and children. Emotional distress: Excessive crying, irritability, difficulty soothing, anxiety. Sleep disturbances: Frequent waking, difficulty falling asleep, restless sleep. Feeding aversion: Refusal to eat, poor weight gain, anxiety around feeding. Social withdrawal: Avoidance of social situations, isolation. Developmental delays: Delayed physical growth, cognitive development, and motor development. Somatization: Increased complaints of stomach pain and discomfort. Behavioral issues: Temper tantrums, restlessness, oppositional behavior. GER: Gastroesophageal reflux.

Functional diarrhea: Functional diarrhea, also referred to as toddler’s diarrhea, is a type of FGID that occurs in infants and young children. It is defined as chronic, watery stools without any structural or biochemical abnormality to explain the condition[229]. While the primary symptoms of functional diarrhea are related to the digestive system, there are significant short-term psychological impacts on affected children, which can have a profound effect on their emotional and behavioral well-being. These impacts are mediated by the stress of recurring symptoms, disruptions to daily life, and potential interactions with caregivers and peers[6]. The unpredictable nature of diarrhea episodes may cause anxiety in young children, especially those in early childhood who are still developing a sense of bodily control. Children may feel confused or frustrated by their inability to manage bowel movements, leading to emotional stress[230]. Older infants and toddlers who have begun potty training or are in daycare environments may experience embarrassment related to frequent accidents. This can affect their confidence and self-esteem. The discomfort caused by frequent bowel movements and abdominal pain can lead to mood changes, irritability, and increased crying or fussiness in younger infants[231].

Children with functional diarrhea may experience significant disruptions to their daily routines. The need for frequent bathroom visits or diaper changes can interfere with activities such as playing, attending daycare, or participating in social events[232]. Toddlers and preschool-aged children may avoid social interactions due to the fear of accidents or being teased by peers. This can lead to social withdrawal, further impacting their psychological well-being. The frequent need for parental intervention may reduce the child's interaction with other children or adults outside the family unit[233]. Limited social playtime can delay the development of key social skills during critical developmental stages. Infants and young children with functional diarrhea often experience disturbed sleep due to discomfort or the need for nighttime bowel movements. This can result in fragmented sleep, leading to daytime irritability, fatigue, and mood swings. The anxiety related to discomfort or the potential for accidents may make it difficult for children to fall asleep. In younger infants, this may be expressed through fussiness and difficulty soothing[234].

Infants and toddlers may exhibit temper tantrums or oppositional behavior due to the frustration and discomfort associated with their condition. This may manifest as defiance toward caregivers during diaper changes, meals, or potty training. Young children experiencing discomfort may become more clingy or seek constant attention and reassurance from their parents. This behavior can strain the parent-child relationship if not managed sensitively[235]. In some cases, the frustration of dealing with recurring diarrhea episodes can lead to aggressive behaviors, such as hitting, biting, or throwing objects. Children with functional diarrhea may become more aware of their bodily functions and overly focused on their symptoms. This can lead to somatization, where they develop a heightened sensitivity to any discomfort, magnifying their distress[236]. While functional diarrhea is typically painless, some children may begin to express frequent complaints of stomach pain or discomfort due to increased attention to their digestive symptoms, even when pain is not directly related to bowel movements[132]. Some children may develop feeding aversions or refuse certain foods they associate with, exacerbating their symptoms. This can lead to anxiety around mealtimes, further complicating the management of their condition. Although functional diarrhea is not typically associated with malabsorption, the perception of poor feeding or the stress of chronic diarrhea can cause concern about weight gain, further increasing anxiety in caregivers and children[94].

Frequent interruptions in daily activities and play due to diarrhea can hinder both cognitive and motor development. Chronic discomfort and social withdrawal may reduce physical and exploratory play engagement, limiting opportunities for motor skill practice[237]. Emotional and social withdrawal, compounded by disrupted daily interactions, can also affect early language development in children, particularly those at a crucial stage of learning language through interaction and play[238]. Functional diarrhea can cause regression in toilet training progress for toddlers learning to use the toilet[239]. Frequent accidents may lead to frustration and anxiety, making children resistant to potty training. Children may develop a fear or aversion to using the toilet due to negative experiences, such as painful bowel movements or accidents[240]. This can lead to emotional distress and further setbacks in toilet training. Infants and young children with functional diarrhea may depend more on their caregivers. The need for frequent diaper changes, monitoring, and clean-up can make children more reliant on their parents, reducing their sense of independence. Functional diarrhea can increase parental stress, mainly when it is recurrent or difficult to manage[241]. The child may sense this tension, leading to anxiety or behavioral changes. Continuous health problems and the caregiving burden may disrupt normal attachment patterns between children and their parents or caregivers. This can lead to emotional imbalances, mainly if the parents express frustration or distress over the condition[242].

CVS: CVS is a FGID characterized by recurrent episodes of severe nausea and vomiting, followed by symptom-free periods. The cause of CVS is unclear, but it is believed to involve genetic, autonomic, and psychological factors[117]. The unpredictable nature of CVS episodes can be particularly distressing for infants and children, leading to a range of short-term psychological impacts that influence their emotional well-being, behavior, and social development[243]. Children with CVS often experience high levels of anxiety, especially due to the unpredictability of vomiting episodes. The uncertainty surrounding the next episode can create anticipatory stress, making children anxious even during symptom-free periods. The intensity of vomiting episodes can cause children to develop a fear of vomiting, known as emetophobia[111]. This can result in heightened anxiety during early signs of an episode, such as nausea or discomfort. Recurrent vomiting episodes can be emotionally exhausting for children, especially when they occur frequently. The physical toll of vomiting combined with emotional stress may leave children feeling drained, upset, or even detached. The recurring and intense nature of CVS episodes can lead to mood swings and irritability in children[244]. They may feel frustrated and overwhelmed by the lack of control over their symptoms, and this can manifest as increased irritability toward caregivers and peers[245].

Recurrent vomiting episodes can disrupt a child’s routine, leading to missed days at school, daycare, or other social activities. The unpredictability of CVS episodes means that children and families often must modify their schedules to accommodate the child's condition. Children may withdraw socially due to the fear of having an episode in public[243]. This avoidance behavior can prevent them from engaging in social interactions, attending events, or playing with peers. As a result, they may feel isolated, further contributing to emotional distress. Social withdrawal can impact a child's ability to establish and maintain friendships, especially if the child frequently misses school or social events. Fear of embarrassment from vomiting in front of others may lead children to isolate themselves, which can delay the development of social skills[246]. Vomiting episodes can disrupt a child’s sleep schedule, leading to fragmented sleep or even complete sleep loss during acute phases. The lack of restful sleep can further exacerbate irritability, anxiety, and emotional instability. Children with CVS may develop a fear of nighttime episodes, which can lead to difficulty falling asleep[108]. In some cases, children may become anxious around bedtime due to a fear of waking up sick, leading to bedtime resistance and sleep disturbances. Chronic sleep disturbances during vomiting episodes can result in daytime fatigue, irritability, and behavioral problems, such as temper tantrums or defiance[247].

Children dealing with the physical discomfort of vomiting may respond with temper tantrums or oppositional behavior, especially when they feel overwhelmed by their symptoms. This frustration can be directed toward caregivers or siblings. Children may become more fearful and clingier to their caregivers during or following vomiting episodes, seeking constant reassurance and emotional support[159]. This increased need for attention can affect the child's independence and self-confidence. Some children may exhibit regressive behaviors, such as a return to earlier developmental stages, as a result of the emotional stress caused by CVS episodes. This may include difficulties with toilet training, separation anxiety, or reliance on comfort items[248]. Children with CVS may develop an exaggerated focus on their physical symptoms, which can lead to somatization, where they report physical discomforts beyond their vomiting episodes. Complaints of headaches, abdominal pain, or general malaise may become more frequent, even when not experiencing an acute episode. Due to the recurring nature of vomiting episodes, children often become hyper-aware of their bodily cues, interpreting even mild discomfort as a sign of an impending episode. This can trigger anxiety and cause a preoccupation with their physical health[109].

Recurrent vomiting episodes can lead to feeding aversion, where the child begins to associate eating with the onset of vomiting. This can result in refusal to eat or selective eating patterns, which may complicate nutritional intake and growth[249]. The physical toll of cyclic vomiting episodes, combined with feeding aversion, may lead to weight loss or poor weight gain in young children. This can heighten parental anxiety, which may be sensed by the child, further contributing to emotional stress. The emotional and physical strain of cyclic vomiting, along with disruptions in daily routines and school attendance, may hinder cognitive development in children[250]. These children may have difficulty concentrating, learning, or retaining information due to fatigue or stress. In infants and toddlers, recurrent vomiting episodes may lead to delays in motor skill development, as children may be less engaged in physical activities during or after episodes of illness. Additionally, social withdrawal and emotional distress can hinder language and social development[159].

Even during symptom-free periods, children with CVS may experience psychosomatic symptoms, such as complaints of stomach pain or discomfort. This can be due to heightened awareness of their GI system and anxiety about future episodes. Psychological stress is often associated with an increased likelihood of CVS episodes or symptom worsening[246]. Children who experience emotional distress, anxiety, or tension may trigger or exacerbate their vomiting episodes, creating a vicious cycle of stress and physical symptoms. Infants and young children experiencing cyclic vomiting become more dependent on their caregivers, particularly during acute episodes[247]. The child’s reliance on parents or caregivers for comfort, medical attention, and basic needs can reinforce attachment behaviors, resulting in increased clinginess. The psychological well-being of caregivers is often affected when dealing with CVS. Parents may experience stress, anxiety, and a sense of helplessness while managing their child’s symptoms[226]. Children can sense this tension, which in turn exacerbates their own anxiety and emotional distress. Continuous caregiving during severe episodes may disrupt regular parent-child interactions. The intense caregiving demands during vomiting episodes can strain the relationship, sometimes leading to frustration, guilt, or confusion on the child’s part[251].

IBS: IBS is a common FGID characterized by recurrent abdominal pain and changes in bowel habits (diarrhea, constipation, or both). IBS can significantly affect a child’s quality of life, and its psychological impacts are often profound, especially in the short term[127]. The condition can lead to emotional distress, behavioral changes, and disruptions in social and academic functioning. Children with IBS often experience anxiety related to the unpredictability of their symptoms. The fear of experiencing sudden abdominal pain or needing to use the bathroom can create anticipatory stress, particularly in social situations such as school or outings[131]. The potential for incontinence or needing to urgently use the bathroom can lead to a fear of embarrassment. This fear can cause children to become overly anxious in public settings, further exacerbating their stress and emotional instability. Chronic pain and discomfort from IBS can lead to feelings of sadness, frustration, and helplessness[101]. Children may struggle with managing their condition, which can result in low mood and feelings of despair. Persistent discomfort and pain can make children more irritable and prone to mood swings. They may become easily frustrated with their symptoms, leading to tension in relationships with caregivers and peers[149].

Children with IBS may withdraw from social activities due to fears of having a bowel movement or experiencing pain in front of others. This avoidance behavior can reduce opportunities for social interaction, play, and friendships[152]. Prolonged social withdrawal can lead to feelings of isolation and loneliness, especially when children miss school, extracurricular activities, or social gatherings due to IBS symptoms. IBS can make it difficult for children to maintain consistent participation in group activities or school, which can hinder their ability to form and sustain friendships[153]. Fear of being judged or misunderstood by peers can also contribute to feelings of isolation. Children with IBS often miss school due to abdominal pain, discomfort, or frequent trips to the bathroom. This absenteeism can affect their academic performance, leading to stress and anxiety about falling behind in their studies[131]. The pain and discomfort associated with IBS can make it hard for children to focus on schoolwork, even when they are in the classroom. Persistent abdominal pain or the fear of a sudden need to use the bathroom can cause distraction and difficulty concentrating on lessons. Some children may develop a fear of going to school due to concerns about managing their symptoms in the school setting. This fear can contribute to school refusal or increased anxiety about attending school[154].

Children with IBS may exhibit increased irritability and oppositional behavior as a result of chronic discomfort and frustration. They may have temper tantrums or act out when they are in pain or feeling overwhelmed by their symptoms. The distress caused by IBS symptoms can make children more dependent on their caregivers for comfort and reassurance[255]. They may become more clingy or seek constant attention, especially during painful episodes. Children with IBS may begin to avoid activities that they associate with worsening symptoms, such as eating certain foods or engaging in physical play[256]. This avoidance can limit their ability to enjoy typical childhood activities and contribute to feelings of frustration. Children with IBS may become hyper-aware of their bodily sensations, focusing intensely on symptoms such as abdominal pain, bloating, or the need to use the bathroom. This hyper-awareness can lead to heightened anxiety and a preoccupation with their physical health[135]. Anxiety about IBS symptoms can lead to a phenomenon known as somatization, where psychological distress manifests as amplified physical pain. This can create a cycle where stress worsens pain, and pain worsens stress[101].

Children with IBS may develop anxiety around eating, particularly if certain foods seem to trigger their symptoms. This can lead to food avoidance or restrictive eating behaviors, which can negatively impact their nutritional intake and growth. Due to the fear of triggering IBS symptoms, children may become highly selective in their food choices, avoiding foods that they perceive as harmful or symptom-inducing[257]. This behavior can contribute to poor dietary habits and nutritional deficiencies. The combination of feeding aversion, selective eating, and GI symptoms can lead to weight loss or poor weight gain in children with IBS, which can further exacerbate their emotional and physical well-being[258]. The pain and discomfort associated with IBS can make it difficult for children to fall asleep, leading to prolonged periods of wakefulness at night. Anxiety about experiencing pain or needing to use the bathroom can further disrupt sleep onset. Some children with IBS experience symptoms such as abdominal pain or diarrhea at night, leading to frequent waking and disrupted sleep patterns[259]. These sleep disturbances can contribute to fatigue, irritability, and difficulty concentrating during the day. Poor sleep quality and frequent waking can lead to daytime fatigue, which can affect a child's mood, behavior, and ability to engage in school and social activities[260].

The pain and discomfort associated with IBS can distract children from academic and cognitive tasks. Children may find it difficult to concentrate or engage in learning activities when they are preoccupied with managing their symptoms. Children with IBS may struggle with regulating their emotions due to the stress and anxiety associated with their condition[261]. This can result in emotional outbursts or difficulty managing frustration in social and academic settings. The fear of symptom exacerbation can lead children to avoid physical activities, which can delay physical development and reduce opportunities for social interaction and skill-building. IBS can cause significant stress for parents, particularly when their child is in pain or struggling with the emotional impact of their symptoms[131]. Parental anxiety and worry can, in turn, increase the child’s own anxiety, creating a feedback loop of stress. Parents may become overly protective of their children in response to their IBS symptoms, limiting their child’s independence and reinforcing feelings of dependency[73]. This overprotectiveness can hinder the child's development of coping skills and autonomy. The stress of managing a child’s chronic condition can create tension within the family, particularly if other siblings feel neglected or if parents disagree on how to best support the child. This family stress can exacerbate the child’s emotional distress[262].

FAP: FAP is one of the most common types of FGIDs in children, characterized by recurrent or chronic abdominal pain that is not associated with any identifiable organic cause. FAP can lead to significant short-term psychological effects, particularly in infants and children, as they grapple with both the physical pain and the psychological burden that accompanies it[163]. The psychosomatic nature of FAP highlights the close connection between mental well-being and GI health, with stress, anxiety, and emotional distress frequently exacerbating physical symptoms. Children with FAP often develop a heightened fear of pain episodes. This anticipation of pain can create ongoing anxiety, especially since the pain tends to be unpredictable and may strike at any time, causing considerable emotional distress[263]. The chronicity of FAP can lead to generalized anxiety, especially in children who struggle to cope with the uncertainty surrounding their symptoms. They may worry excessively about when the next episode of pain will occur, how severe it will be, and whether it will interfere with their daily activities. Persistent discomfort and the accompanying emotional strain can result in irritability and mood swings. Children may feel frustrated, angry, or helpless due to their inability to control their symptoms, leading to emotional outbursts[264].

Children with FAP may avoid social situations out of fear that pain will occur in public or around peers. This withdrawal can lead to feelings of loneliness and isolation, as children begin to miss out on social interaction and play opportunities with friends[253]. Many children with FAP may avoid extracurricular activities like sports, school events, or recreational outings due to fears of pain episodes or the need to be close to a restroom. This avoidance can reduce opportunities for physical activity, socialization, and skill development. The frequent avoidance of social activities and absenteeism from school can strain peer relationships, leading to feelings of exclusion[265]. Children with FAP may have trouble maintaining friendships due to their unpredictable attendance or reluctance to join in group activities. One of the most significant impacts of FAP is school absenteeism. Children with FAP often miss school due to their symptoms, whether because of the severity of the pain or their emotional distress surrounding it[266]. This can lead to academic challenges, as children fall behind in their studies or struggle to keep up with their peers. Even when children with FAP are physically present in school, the distraction of ongoing abdominal discomfort can make it difficult for them to concentrate on schoolwork. The mental energy spent worrying about their symptoms can detract from their ability to focus on lessons, assignments, and tests[264]. In some cases, the emotional and physical toll of FAP may lead to school refusal, where children develop a strong aversion to attending school due to their symptoms. This can contribute to increased anxiety and stress in both the child and their caregivers[267].

Children with FAP may exhibit oppositional behavior or temper tantrums in response to their pain and the frustration it brings. They may lash out at caregivers or siblings when experiencing discomfort or become defiant about participating in daily activities such as attending school or eating meals[268]. The unpredictability of FAP episodes can lead children to become more dependent on their caregivers for comfort and reassurance. Some children may exhibit clinginess, seeking constant attention and support from their parents or guardians during or after pain episodes. Children may start to avoid activities they associate with triggering pain, such as eating certain foods, attending sports events, or even participating in physical play[269]. This can limit their engagement in normal childhood activities, leading to frustration, sadness, or behavioral regression. The anxiety and physical pain associated with FAP can interfere with a child’s ability to fall asleep. Worries about when the next pain episode will occur or discomfort from the pain itself can lead to prolonged periods of wakefulness at bedtime[270]. Children with FAP may experience pain that wakes them in the middle of the night, disrupting their sleep patterns. This can contribute to daytime fatigue, irritability, and difficulty concentrating during school or other activities. The poor sleep quality resulting from nighttime pain episodes can lead to fatigue, making it harder for children to engage in daily tasks. Fatigue can compound the psychological impacts of FAP, contributing to irritability, mood swings, and difficulty coping with stress[271].

Many children with FAP develop anxiety around eating, fearing that certain foods might exacerbate their pain. This can lead to food avoidance or restrictive eating behaviors, where children limit their intake to avoid triggering symptoms. As children start avoiding certain foods they associate with pain, they may become selective eaters, which can lead to poor nutritional intake[272]. In the short term, this can contribute to weight loss or poor weight gain, which further exacerbates emotional distress and physical discomfort. The combination of selective eating and anxiety around food can result in poor weight gain or even weight loss, particularly if the child’s FAP is prolonged[273]. This can be particularly concerning in infants and young children, as it may lead to developmental delays or poor growth patterns. Children with FAP often become hyper-focused on their physical symptoms, paying close attention to sensations in their abdomen. This heightened awareness can lead to increased anxiety, where even minor sensations are interpreted as severe pain or the precursor to a significant episode[163]. Emotional stress and anxiety can manifest as amplified physical symptoms in children with FAP. Stressful situations, such as school pressures or family conflicts, may worsen abdominal pain, leading to a cycle where emotional distress contributes to physical discomfort and vice versa[116].

The chronic nature of FAP can result in cognitive distraction, where children struggle to focus on academic tasks or engage in problem-solving due to the ongoing pain or fear of pain. This can lead to difficulty keeping up with schoolwork and hinder intellectual development in the short term[274]. Infants and young children with FAP may experience delays in reaching developmental milestones due to chronic pain and discomfort. Poor nutritional intake, sleep disturbances, and a lack of physical activity can all contribute to slower growth and cognitive or motor delays[275]. FAP not only impacts the child but also causes significant stress for parents, who may feel helpless in alleviating their child’s pain. This parental stress can increase the child’s own anxiety, creating a feedback loop of emotional tension within the household. Parents of children with FAP may become overly protective in an attempt to prevent pain episodes, limiting the child’s independence and contributing to increased dependency[276]. This overprotectiveness can hinder the child’s ability to develop coping mechanisms and resilience in dealing with their condition. Siblings of children with FAP may feel neglected due to the attention focused on managing the affected child’s symptoms. This can create tension within the family, contributing to feelings of resentment or frustration[277].

AM: AM is a subtype of FGIDs in which children experience episodes of severe abdominal pain, often accompanied by nausea, vomiting, pallor, and lethargy, but without any organic cause[165]. These symptoms can significantly affect a child's psychological well-being in the short term, especially given the unpredictable and recurrent nature of the condition. The physical discomfort of AM is closely intertwined with psychological distress, leading to various emotional, social, cognitive, and behavioral impacts. Children with AM may develop significant anxiety surrounding the unpredictability of their pain episodes[170]. Not knowing when or where a migraine will strike can lead to ongoing worry and fear, affecting their sense of security and daily functioning. The recurrent nature of AM can contribute to generalized anxiety, particularly if the child has frequent or severe episodes. This may manifest as nervousness, apprehension, or excessive worry about a wide range of situations, both related and unrelated to the migraines[168]. Children experiencing AM often exhibit mood swings, irritability, or temper tantrums. These emotional outbursts can stem from the frustration of dealing with recurrent pain, as well as feelings of helplessness and fear[278].

Pain episodes, especially those occurring at night, can disrupt a child’s ability to fall asleep, leading to bedtime anxiety and difficulty relaxing. The fear of waking up in pain can also interfere with a child’s ability to settle down for the night[279]. Children with AM may experience sleep interruptions due to nighttime pain or nausea. These disruptions can prevent restorative sleep, leading to daytime fatigue, irritability, and a weakened ability to cope with stress[168]. The combination of anxiety, pain, and poor sleep quality can result in daytime drowsiness, reducing the child’s energy levels and impairing their performance in school and other daily activities. The chronic pain and emotional distress associated with AM can lead to oppositional behaviors, such as refusal to participate in daily activities, resistance to attending school, or temper tantrums[280]. These behaviors may be the child's way of expressing frustration with their condition. Children with AM may become more dependent on their caregivers for comfort and reassurance, particularly during or after painful episodes. This increased clinginess may reflect their anxiety about future episodes and their need for emotional support[169]. Children with AM may start to avoid activities they associate with triggering pain, such as eating certain foods, engaging in physical play, or attending social events. This avoidance can limit their participation in normal childhood activities and contribute to frustration, sadness, or withdrawal[136].

The recurrent nature of AM often results in frequent school absenteeism. Children may miss multiple days of school due to severe pain, nausea, and other symptoms, which can lead to academic challenges and gaps in learning[281]. Even when present in school, children with AM may struggle to concentrate due to lingering pain or fear of an impending episode. This distraction can make it hard for them to keep up with their studies or stay engaged during lessons. In more severe cases, children may develop an aversion to school due to the anxiety of experiencing an AM episode while away from home. This school refusal can cause academic setbacks and create tension within the family as parents attempt to manage the child’s health and education[282]. Children with AM may withdraw from social situations out of fear of experiencing pain or nausea in public. This avoidance can lead to isolation, as children may stay home rather than participate in activities with peers. Social withdrawal and frequent absenteeism from school or extracurricular activities can strain peer relationships[283]. Children with AM may find it difficult to maintain friendships due to their unpredictable participation in social events, leading to feelings of loneliness or rejection[284]. The physical discomfort and anxiety surrounding AM episodes can reduce a child’s willingness to engage in physical activities, such as sports or playtime with friends. This avoidance can limit their opportunities for socialization, physical development, and stress relief[165].

Children with AM may become hypervigilant about their physical sensations, paying close attention to any signs of pain, nausea, or discomfort. This hyperawareness can increase their anxiety and make them more prone to somatization, where emotional stress is expressed as physical symptoms[168]. The emotional distress caused by AM may lead children to exaggerate the severity of their physical symptoms, particularly if they are already anxious about experiencing pain. This somatization can create a cycle where emotional stress and physical discomfort reinforce one another[170]. Children with AM may frequently report complaints of abdominal discomfort, even between episodes. These complaints may be linked to heightened anxiety, stress, or the anticipation of a future migraine, making it difficult for caregivers to distinguish between genuine pain and anxiety-driven symptoms[285]. Children with AM may develop anxiety around eating, particularly if they believe certain foods or eating habits trigger their pain episodes. This food-related anxiety can lead to restrictive eating behaviors, where children limit their intake to avoid triggering symptoms. As children avoid certain foods, they may become selective eaters, which can lead to poor nutritional intake in the short term[286]. The fear of triggering a migraine may cause children to eat smaller portions or avoid entire food groups, potentially resulting in poor weight gain or malnutrition. In more severe cases, the combination of selective eating, poor nutrition, and anxiety around food can result in weight loss or delayed growth in young children[287]. These nutritional deficiencies may further impact the child’s overall physical and cognitive development.

The chronic pain and emotional distress caused by AM can lead to cognitive distraction, where children struggle to focus on academic tasks, social interactions, or even recreational activities[165]. This distraction can hinder a child’s intellectual development and lead to academic difficulties in the short term. Infants and young children with frequent or severe AM episodes may experience delays in their developmental milestones[169]. Pain episodes, nutritional deficiencies, and sleep disturbances can all contribute to slower growth and cognitive or motor delays. The unpredictable nature of AM can cause significant stress for parents, who may feel anxious about their child’s well-being and the frequency of pain episodes[285]. This parental anxiety can increase the child’s own stress levels, creating a cycle of emotional tension within the household. Parents may become overly protective in an attempt to prevent migraine episodes, limiting the child’s independence[73]. This overprotection can result in increased dependency and a lack of opportunity for the child to develop coping mechanisms or resilience in managing their condition. The focus on managing the affected child’s AM can also strain sibling relationships, as siblings may feel neglected or resentful of the attention their brother or sister receives[288]. This dynamic can create tension within the family and further exacerbate the child’s feelings of isolation or guilt. Table 3 summarizes the short-term psychological impacts of the FGIDs in infants and children.

Table 3 The short-term psychological impacts of functional gastrointestinal disorders in infants and children.

FGID	Emotional impacts	Sleep impacts	Behavioral impacts	Social impacts	Cognitive/academic impacts	Somatic & physical impacts	Parental/family dynamics
Infant colic	Excessive crying, irritability, heightened anxiety in both infant and caregiver	Sleep disruption due to frequent crying and inability to soothe	Temper tantrums, irritability, emotional dependency	Strain in caregiver-infant bonding, parental frustration	Limited cognitive growth if stress persists	Physical discomfort, feeding difficulties	Increased parental stress, feelings of helplessness, strained family dynamics due to constant soothing efforts
Functional constipation	Anxiety related to bowel movements, frustration from discomfort	Restless sleep due to discomfort	Avoidance of toileting, fear of painful bowel movements	Avoidance of social situations like school or playdates due to fear of accidents	Difficulty concentrating at school, anxiety-driven distractions	Somatization of abdominal pain, stool withholding behaviors	Increased parental worry and intervention; pressure on family dynamics as caregiving intensifies
GER	Anxiety around feeding, irritability, excessive crying, emotional distress related to discomfort	Interrupted sleep due to pain or discomfort from reflux	Feeding aversion, refusal to eat, tantrums around mealtime	Social withdrawal due to irritability, reluctance to participate in feeding situations	Impaired cognitive development due to poor nutrition or sleep deprivation	Poor weight gain, feeding difficulties, heightened focus on somatic symptoms	Parental anxiety regarding feeding and health, increased stress from constant monitoring of symptoms
Functional diarrhea	Frustration, anxiety related to frequent bowel movements	Sleep disturbances due to frequent nocturnal diarrhea	Avoidance of foods, temper tantrums, anxiety-driven irritability	Social withdrawal due to embarrassment over bowel movements or accidents	Difficulty concentrating in school, absenteeism due to frequent episodes of diarrhea	Somatic complaints like stomach cramps and discomfort	Increased family stress around toileting and diet, tension from dealing with frequent accidents
Cyclic vomiting syndrome	Extreme emotional distress related to unpredictable vomiting episodes, fear of nausea	Sleep disturbances during vomiting episodes, fatigue after episodes	Avoidance of food, reluctance to eat, oppositional behaviors around eating	Withdrawal from social activities to avoid public vomiting, avoidance of mealtimes with others	Missed school days, academic setbacks from frequent episodes, cognitive distraction from fear of vomiting	Dehydration, weight loss, malnutrition due to feeding aversion	High parental anxiety and stress in managing episodic care, tension in family dynamics due to medical uncertainty
IBS	Anxiety about pain or discomfort, emotional distress from unpredictability of symptoms	Difficulty falling asleep due to pain or abdominal discomfort	Fear-driven avoidance of activities, irritability, mood swings	Social isolation due to unpredictability of bowel movements, avoidance of peer interactions	Academic challenges due to absenteeism, difficulty concentrating due to pain and worry	Increased complaints of abdominal pain, potential somatization of discomfort	Parental stress around managing symptoms, anxiety in helping child avoid flare-ups, family tension during episodes
Functional abdominal pain	Emotional distress linked to chronic pain, frustration due to lack of relief from discomfort	Sleep interruptions due to ongoing pain, difficulty falling asleep	Increased tantrums, mood swings, irritability	Social withdrawal, avoidance of activities due to fear of pain episodes	Cognitive distraction due to pain, frequent absenteeism, academic underperformance	Frequent complaints of stomach pain, somatization of emotional distress	Parental anxiety, frustration over not finding relief, overprotective behaviors from caregivers
Abdominal migraine	Anxiety related to unpredictability of episodes, emotional distress due to recurrent pain	Interrupted sleep due to abdominal pain episodes, difficulty falling asleep	Avoidance of food or social activities, mood swings, oppositional behaviors	Social withdrawal, avoidance of peer interactions due to fear of episodes	Missed school days, concentration difficulties, academic delays linked to frequent absences	Somatization, frequent complaints of pain, feeding aversion, poor weight gain	Increased parental stress, family disruption due to focus on managing pain episodes

This table outlines the major psychological, social, cognitive, and physical impacts that each functional gastrointestinal disorder can have on children in the short term. It highlights the complexity of these conditions and their effect on a child's overall well-being and family dynamics. GER: Gastroesophageal reflux; FGID: Functional gastrointestinal disorder; IBS: Irritable bowel syndrome.

Long-term social and psychological impacts of FGIDS in infants and children: FGIDs in infants and children, when persistent, can lead to profound long-term social and psychological impacts. These disorders, which include conditions like GER, FC, FAP, and IBS, can create patterns of discomfort and distress that shape a child’s emotional well-being, social interactions, and developmental trajectory[289]. Among these impacts are the development of chronic anxiety, mode disorders, social isolation and withdrawal, negative impact on impact on self-esteem and self-concept, impaired academic performance and school participation, impaired coping mechanisms, increased risk of developing mental health disorders, impaired long-term relationships and social development, and poor family dynamic[290] (Table 4).

Table 4 The long-term social and psychological impacts of functional gastrointestinal disorders in infants and children, organized by the frequency and typical time of development for each impact.

Impact	Description	Frequency	Time of development
Chronic anxiety	Ongoing fear of symptom recurrence; anticipatory anxiety related to potential triggers or social interactions	High	Childhood, worsening in adolescence
Social anxiety	Fear of social situations due to concerns about symptoms (e.g., needing the restroom, pain episodes)	Moderate	Childhood, but may persist long-term
Depression	Feelings of sadness, hopelessness, and frustration due to limitations & missed social or academic opportunities	Moderate	Late childhood to adolescence
Social isolation	Avoidance of social activities and interactions leads to a sense of loneliness and isolation	High	Childhood, especially during school
Low self-esteem	Negative self-perception due to perceived limitations or differences from peers	High	Childhood, may continue long-term
Body image concerns	Poor body image due to physical symptoms (e.g., bloating, weight changes)	Moderate	Late childhood to adolescence
Poor academic performance	Difficulty concentrating, frequent absenteeism, falling behind in school	Moderate	Childhood, can persist with chronic symptoms
Maladaptive coping mechanisms	Use of avoidance behaviors, over-reliance on caregivers, or negative coping strategies like self-isolation	Moderate	Late childhood to adolescence
Difficulty forming friendships	Challenges in establishing and maintaining peer relationships due to social avoidance and anxiety	High	Childhood, worsening over time
Risk of mood and behavioral disorders	Vulnerability to mood disorders like depression & behavioral disorders like ODD	Moderate	Adolescence
Somatization and health anxiety	Heightened focus on physical symptoms and preoccupation with health concerns	Moderate	Late childhood to adolescence
Parental stress and burnout	Parents may experience increased stress, affecting family dynamics and parent-child relationships	High	Childhood, ongoing
Strained sibling relationships	Tension and conflict with siblings who feel neglected or resentful of the affected child’s needs	Moderate	Childhood, may continue with stressors
Nutritional deficits	Malnutrition due to feeding issues and avoidance behaviors; impacts physical and cognitive development	High	Childhood, early intervention needed
Increased risk of eating disorders	Disordered eating behaviors due to restrictive eating patterns to avoid symptoms	Low	Adolescence
Impaired physical development	Limited physical activity and play, affecting fitness, motor skill development, and physical growth	Moderate	Childhood to adolescence

The table shows the types of impacts based on how frequently they occur and the typical time of development. Higher frequency impacts tend to develop early and persist, while some impacts, particularly behavioral and mood disorders, may appear later as the child grows older. ODD: Oppositional defiant disorder.

Chronic anxiety and mood disorders: FGIDs often cause recurrent episodes of pain and discomfort, which can lead to anticipatory anxiety. Children may become hypervigilant about potential symptoms, particularly in social or unfamiliar settings, where they may worry about experiencing pain or needing to visit the restroom frequently. This ongoing anxiety can become chronic, making children more prone to GAD as they age[132]. For children with FGIDs, symptoms can be embarrassing or disruptive in social contexts, such as school or social gatherings. This can create social anxiety, as children may fear being embarrassed in front of their peers, leading to avoidance behaviors[291]. Over time, this avoidance can restrict their social lives, causing them to miss out on key social development opportunities. The chronic nature of FGIDs can lead to feelings of hopelessness, sadness, and frustration. If symptoms interfere with daily activities and prevent children from participating in things they enjoy, these feelings can contribute to the development of depressive symptoms. Children may also experience negative self-perception due to their limitations, which can further contribute to long-term depression[292].

Social isolation and withdrawal: Children with FGIDs often avoid social situations due to concerns about symptoms or the need for frequent restroom breaks. This can limit their interaction with peers, reducing their opportunities to form friendships and experience positive social connections. As a result, they may feel isolated or left out, reinforcing a sense of loneliness[161]. Physical activities and team sports may exacerbate symptoms like abdominal pain, discomfort, or urgency to use the restroom. Consequently, children may avoid group activities, sports, or other physical engagements, crucial for developing teamwork skills, building friendships, and fostering a sense of belonging[293]. FGIDs can also affect family dynamics. Due to the child's symptoms, family outings, vacations, and gatherings may be limited. Siblings and other family members might feel restricted or frustrated by the need to accommodate the child’s condition, potentially leading to tension within the family[183].

Impact on self-esteem and self-concept: Repeated episodes of pain, discomfort, and social avoidance can erode a child’s self-esteem. They may feel "different" or less capable than their peers, leading to negative self-perception. Constantly dealing with a chronic condition can lead children to believe that they are weak or fragile, which can persist into adolescence and adulthood[290]. Children with FGIDs may develop body image issues if they perceive their symptoms as embarrassing or if their condition affects their physical appearance (e.g., bloating or changes in weight due to dietary restrictions). Additionally, the impact of chronic illness on self-image may increase vulnerability to eating disorders, especially if children adopt restrictive eating patterns to manage symptoms[291]. FGIDs can create feelings of helplessness, as symptoms often occur unexpectedly and are beyond the child’s control. This lack of control can affect how children view themselves and their ability to cope with challenges, leading to an external locus of control, where they feel unable to influence their circumstances[294].

Challenges in academic performance and school participation: Chronic symptoms can cause children to miss school frequently, which affects their academic performance. Frequent absences can disrupt learning and make it challenging for children to keep up with their peers. Falling behind academically can increase stress, reinforce negative self-perceptions, and lead to feelings of failure[295]. Symptoms like pain, discomfort, or fatigue can interfere with a child’s ability to concentrate in school. This can make it harder to complete assignments, pay attention in class, and engage in learning activities. Poor concentration, in turn, affects academic achievement and motivation[296]. Due to absences and symptoms, children with FGIDs may struggle to build relationships with teachers and classmates. They may feel misunderstood by peers or receive less attention from teachers, especially if their symptoms are not readily visible. This can further contribute to feelings of isolation and frustration[297].

Development of maladaptive coping mechanisms: To cope with their symptoms, children with FGIDs may start to avoid activities or situations where they anticipate discomfort. This can range from avoiding social interactions to refraining from physical activities. While these behaviors may provide temporary relief, they often prevent children from developing healthy coping skills and can lead to more significant challenges as they grow older[298]. Children with chronic FGIDs may develop a heightened dependence on parents or caregivers for comfort and reassurance. While it is natural for children to seek support, excessive dependence can hinder the development of independence and self-reliance, as children may feel incapable of managing their symptoms on their own[289]. As children become adolescents, they may turn to maladaptive behaviors such as substance use, self-isolation, or self-harm to cope with chronic discomfort and emotional distress. These behaviors can exacerbate their mental health challenges and lead to further psychological and social difficulties[299].

Impact on long-term relationships and social development: Due to social withdrawal and avoidance behaviors, children with FGIDs may have limited opportunities to develop the social skills necessary for forming friendships. They may struggle with trust, communication, and social reciprocity, which are crucial for healthy relationships[300]. Limited social interaction can lead to deficits in social skills, including assertiveness, empathy, and conflict resolution. These skills are essential for navigating social situations and building meaningful connections, and deficits in these areas can contribute to feelings of isolation and loneliness[301]. As children with FGIDs grow into adolescence and adulthood, they may experience challenges in forming romantic relationships. Chronic health issues can lead to fears about intimacy and vulnerability, particularly if they have a poor self-image or concerns about their symptoms affecting their relationships[1].

Risk for developing other mental health disorders: The chronic nature of FGIDs, combined with social isolation and perceived limitations, can contribute to a long-term risk of depression. Children who experience ongoing frustration and sadness due to their condition may develop persistent feelings of hopelessness, worthlessness, and disinterest in previously enjoyable activities[253]. Over time, children with FGIDs may become preoccupied with physical symptoms, leading to an increased focus on bodily sensations. This can manifest as somatization, where children report various physical complaints that are not explained by a medical condition, or health anxiety, where they worry excessively about their health[31]. Long-term psychological stress and frustration can contribute to the development of behavioral disorders, such as oppositional defiant disorder or conduct disorder. Children may act out as a means of coping with their symptoms, and over time, these behaviors can become ingrained patterns of responding to stress and adversity[159].

Impact on family dynamics and relationships: Parents of children with FGIDs often experience stress and burnout due to the demands of managing a chronic condition. This can lead to parental mental health issues, including anxiety and depression, which can affect the parent-child relationship and the family dynamic as a whole[302]. Siblings of children with FGIDs may feel neglected or resentful if they perceive that their parents’ attention is primarily focused on the affected child. This can lead to jealousy, conflict, and strained sibling relationships[303]. In some cases, children with FGIDs may take on a role of heightened dependency on their parents, which can hinder their development of independence. This dependency can sometimes create a role reversal where parents feel compelled to protect their child from discomfort, limiting opportunities for the child to develop self-management skills[304].

Impacts on physical health and development: Persistent feeding issues related to FGIDs can lead to nutritional deficits, which can impact physical growth and overall development. Malnutrition can have long-term consequences on physical health, cognitive development, and mental health. Children with a history of FGIDs may develop a fraught relationship with food, increasing their risk of developing eating disorders[289]. For example, children with FC or GER might develop restrictive eating patterns to avoid triggering symptoms, which can evolve into more serious eating disorders. Discomfort associated with FGIDs may limit physical activity, affecting overall fitness and motor skill development. Physical play and exercise are crucial for developing coordination, strength, and a healthy body image, all of which are important for long-term physical and mental health[305].

Diagnosis and management of the psychological impacts of FGIDS in infants and children: Diagnosing and managing the social and psychological impacts of FGIDs in infants and children require a multidisciplinary approach involving pediatricians, gastroenterologists, mental health professionals, dietitians, and caregivers. Early and accurate diagnosis is essential for effective management to mitigate long-term consequences and improve the child’s quality of life[306].

Diagnosis: Diagnosing FGIDs and associated psychological impacts typically involves clinical assessment, psychosocial assessment, psychometric and diagnostic tools, and dietary and nutritional assessment. Clinical assessment can be performed with proper history taking and symptom evaluation followed by a head-to-toe physical examination[307]. A comprehensive medical history is crucial. Physicians will evaluate the frequency, duration, and nature of GI symptoms, as well as any changes in appetite, sleep disturbances, or emotional symptoms like irritability, anxiety, and sadness. Physical examination includes assessing for any physical signs that might suggest underlying organic causes[308]. A standard physical examination helps rule out differential diagnoses and identify any potential red flags. Psychosocial assessment can be performed through behavioral observation, psychiatric screening, and family dynamics evaluation[309]. It is important to assess the child’s behavior and emotional responses. Patterns like avoidance behaviors, irritability, or fearfulness in social situations may be early indicators of psychological impacts. A child psychologist or psychiatrist can administer screening tools for anxiety, depression, and other psychological conditions to gauge the impact of FGIDs on mental health. Understanding the family environment and dynamics is also essential, as parental stress, sibling relationships, and family routines can all impact the child’s experience of their symptoms[310] (Figure 5).

Figure 5 The diagnostic approach for assessing the social and psychological impacts of Functional gastrointestinal disorders in infants and children. This radial cycle-style flowchart diagram summarises the diagnostic approach for assessing the social and psychological impacts of functional gastrointestinal disorders in infants and children. It visually connects the central focus on comprehensive assessment with each major diagnostic step, emphasizing an integrative and thorough evaluation process. FGID: Functional gastrointestinal disorder.

Psychometric and diagnostic tools can be used to uncover any hidden psychological impact comprehensively. Child Behavior Checklist is a standardized tool that can assess behavioral and emotional problems and help identify anxiety, depression, and other psychological issues related to FGIDs[311]. Functional Disability Inventory can evaluate the degree of disability in various aspects of daily life due to FGID symptoms[312]. Rome IV Criteria are used for diagnosing FGIDs and can be tailored to screen for specific conditions like IBS, FC, or CVS[313]. The Pediatric Quality of Life Inventory can assess the impact of chronic health conditions on a child’s quality of life, which can also highlight psychological distress[314]. Dietary and nutritional assessment is integral to properly assessing the affected children. They should be nutritionally screened for deficiencies or malnutrition related to feeding issues or restrictive diets. Dietary history plays an essential role in nutritional screening. This includes detailed information on food intake, preferences, and any aversions. Identifying triggers can aid in understanding how FGIDs affect the child’s psychological and social well-being[315]. Figure 5 shows A radial cycle-style flowchart for diagnosing the psychiatric and social sequelae in children with FGIDs.

Management: A holistic approach is required for the effective management of FGIDs in children, addressing both physical symptoms and the accompanying social and psychological impacts.

Medical and pharmacological management can relieve symptoms, and occasionally, psychotropic medications may be needed. Common medicines that relieve symptoms include proton pump inhibitors for GER, antispasmodics for abdominal pain, or laxatives for constipation. Managing physical symptoms often has a positive effect on psychological symptoms. In some cases, medications like selective serotonin reuptake inhibitors are prescribed for children with anxiety or depression linked to FGIDs[70]. These should only be used under the supervision of a psychiatrist.

Behavioral and psychological interventions such as cognitive behavioral therapy (CBT), mindfulness-based stress reduction (MBSR), biofeedback, and exposure therapy significantly improve FGIDs and their psychological effects. CBT is effective in helping children manage stress, anxiety, and depressive symptoms[316]. CBT for FGIDs may focus on coping mechanisms, stress reduction, and altering negative thought patterns related to symptoms. Practices such as meditation, deep breathing, and mindfulness exercises have shown positive effects in reducing the severity of FGID symptoms and alleviating associated anxiety and depression[317]. Biofeedback helps children gain awareness and control over physiological functions. Biofeedback can be particularly useful for children with recurrent abdominal pain, as it allows them to relax their muscles and reduce tension[318]. For children who avoid certain foods or social situations due to symptom fears, gradual exposure therapy can help them learn to engage with previously avoided stimuli without distress[319].

Parental and family education is one of the cornerstones in managing FGIDs, which can be done through psychoeducation, parental support groups, and parent-child interaction therapy (PCIT)[320]. Teaching parents about FGIDs, including symptom triggers and expected outcomes, is essential. Psychoeducation helps parents manage their stress, which indirectly benefits the child. Joining support groups provides parents with emotional support and practical tips on managing their child’s symptoms and reducing family stress[321]. In cases with significant stress or tension between the child and parents, PCIT can improve communication and strengthen relationships[322].

Social and environmental modifications, such as school accommodations, peer support groups, and social skills training, help to alleviate the stress and improve the performance of the affected child[323]. Collaborating with schools to provide accommodations for bathroom access, dietary needs, and flexible schedules helps children manage symptoms without disrupting their education. Interactions with other children experiencing similar symptoms can reduce feelings of isolation and improve self-esteem. Children who have experienced social withdrawal due to FGIDs may benefit from structured social skills training to build confidence and resilience in social situations[324].

Nutritional and dietary interventions, such as dietary modifications, feeding therapy, and probiotics and supplements, can help prevent and manage nutritional deficiencies encountered by infants and children suffering from FGIDs[325]. Depending on the specific FGID, a dietitian may recommend dietary changes such as eliminating trigger foods, implementing a high-fiber diet, or following a low-FODMAP diet. For children with feeding aversions or severe food avoidance behaviors, feeding therapy can help them gradually reintroduce foods, leading to better nutritional intake and reduced anxiety around mealtimes[326]. Probiotics and supplements may be recommended to support gut health, as research suggests the gut-brain axis plays a role in both FGIDs and associated psychological symptoms[327].

Multidisciplinary coordination and follow-up through care coordination, regular monitoring, and early intervention programs are mandatory to detect and manage anticipated complications of FGIDs. Involving multiple specialists such as pediatricians, gastroenterologists, psychologists, and dietitians ensures that the child receives comprehensive care tailored to their unique needs[328]. Monitoring symptoms, psychological impacts, and overall well-being is essential to adjust treatment plans as needed and provide ongoing support. Engaging in early intervention programs can mitigate long-term impacts and support positive developmental outcomes for children at risk of chronic psychological issues related to FGIDs[317]. Figure 6 shows the management process for FGIDs in children.

Figure 6 The management process for functional gastrointestinal disorders in children. FGID: Functional gastrointestinal disorder.

Recommendation: A holistic and multidisciplinary approach is essential for the effective management of FGIDs in children, addressing both GI symptoms and associated psychological impacts. Collaboration among pediatricians, gastroenterologists, psychologists, dietitians, and educators ensures that care is tailored to each child's unique needs. Early identification and intervention are crucial for minimizing long-term psychological effects; thus, screening tools should be routinely used to detect early signs of anxiety, depression, or social withdrawal in children with chronic GI symptoms. Primary care providers and pediatricians should be trained to recognize the signs and symptoms of FGIDs and their psychological impacts to facilitate timely referrals to specialists.

Psychological and behavioral interventions, such as CBT, MBSR, and biofeedback, are recommended to help children develop healthy coping mechanisms. Including these therapies in standard FGID treatment protocols can improve overall outcomes. Additionally, exposure therapy can benefit children who avoid certain foods or situations due to fear of symptom recurrence, providing a controlled, supportive environment to help them gradually overcome these fears.

Parental and family education is a cornerstone of effective FGID management. Since parental anxiety and stress can exacerbate children’s symptoms, psychoeducation should focus on teaching parents strategies to manage their stress and support their child's emotional needs. Family therapy or PCIT may be beneficial for families where FGIDs significantly impact dynamics, helping improve communication, reduce tension, and build resilience in the child.

School and social accommodations are also important. School-based accommodations - such as bathroom access, flexible schedules, and dietary considerations - are essential for supporting children with FGIDs. Teachers and school staff should be educated on the impact of FGIDs to create a supportive learning environment. Peer support groups and social skills training can help these children build confidence, reduce isolation, and enhance their social interactions.

Nutritional interventions play a key role in managing FGID symptoms and preventing nutritional deficiencies. A personalized diet plan, often incorporating high-fiber or low-FODMAP foods, can be beneficial when overseen by a dietitian familiar with pediatric FGIDs. For children with feeding aversions, feeding therapy can assist in reintroducing foods, promoting a balanced diet, and reducing mealtime anxiety.

Research on the long-term psychological impacts of FGIDs in children is needed to better understand these disorders' developmental trajectory. Longitudinal studies assessing how early intervention affects psychological outcomes over time are particularly valuable. Additionally, further investigation into the gut-brain axis's role in FGIDs and associated psychiatric conditions may reveal integrative treatments that address both physical and mental health aspects.

To improve awareness and facilitate early recognition, developing accessible educational materials on FGIDs for families, schools, and healthcare providers is essential. These resources should cover common symptoms, potential psychological impacts, and treatment options. Lastly, advocating for integrated care models that include pediatric and mental health professionals can promote more holistic care for children with FGIDs. Support for policies that cover psychological services for chronic conditions like FGIDs is also important to improve access to necessary care and ensure comprehensive support for affected children.

Limitations

This review article has several limitations that should be acknowledged. First, while the article provides a comprehensive overview of the psychological impacts of FGIDs, it relies heavily on existing literature, which may include studies with varying methodologies, sample sizes, and populations. This variability can affect the generalizability of the findings. Second, due to the vast and continuously evolving nature of the field, the review may not encompass all relevant studies or emerging research. Some important studies on FGIDs and their psychological implications may have been inadvertently excluded, leading to potential gaps in the evidence presented. Third, there is a lack of longitudinal data linking early childhood FGIDs to long-term psychological outcomes. Most studies reviewed are cross-sectional, which limits the ability to draw causal relationships between FGIDs and subsequent mental health issues. Fourth, the psychosocial and emotional factors discussed may not uniformly apply to all populations or cultural contexts. Variability in family dynamics, social support systems, and cultural perceptions of health can influence the experience of FGIDs and their psychological impacts. Yet, these factors may not have been sufficiently explored in the reviewed literature. Lastly, while the review emphasizes the importance of a multidisciplinary approach to managing FGIDs, it does not provide a detailed exploration of how to implement such collaborative care effectively in clinical practice. Practical guidelines for integrating psychological interventions with medical management could enhance the applicability of the findings.

CONCLUSION

FGIDs present a significant challenge in pediatric populations, with profound implications not only for physical health but also for psychological well-being. The complex interplay between GI symptoms and psychological factors underscores the necessity for a comprehensive, multidisciplinary approach to diagnosis and management. This review highlights the bidirectional relationship between FGIDs and various psychiatric conditions, including anxiety, depression, and behavioral issues, which can exacerbate the impact of GI symptoms on a child's quality of life. Early identification and intervention are critical to mitigating the long-term psychological effects of FGIDs. A holistic management strategy encompassing medical treatment, psychological support, dietary modifications, and family education is essential for improving outcomes. By addressing the physical and emotional aspects of FGIDs, healthcare providers can help children develop healthier coping mechanisms, reduce social isolation, and enhance their overall quality of life. Future research is necessary to deepen our understanding of the long-term psychological impacts of FGIDs and to refine treatment approaches. Investigating the gut-brain axis and its role in FGIDs could lead to innovative therapeutic strategies that integrate physical and mental health care. Ultimately, improving awareness and education among healthcare providers, families, and schools about FGIDs and their psychological consequences will foster a more supportive environment for affected children, enabling them to thrive both physically and emotionally.