Mindfulness improves negative psychotic symptoms through reducing emotional and social withdrawal

Abstract

BACKGROUND

Psychotic disorders are characterized by both positive symptoms (hallucinations, delusions) and negative symptoms (emotional blunting, anhedonia) that impair daily functioning. While antipsychotic drugs and psychological interventions are effective when addressing positive symptoms, treatment of negative symptoms remains an ongoing challenge. Mindfulness-based interventions (MBIs) have been shown to reduce negative psychotic symptoms. However, as negative psychotic symptoms are assessed as a sole entity rather than a sum of manifestations, the effect of MBIs remains unclear.

AIM

To examine the effects of MBI in addition to integrated rehabilitation treatment (IRT) for people experiencing psychosis on each of the negative psychotic symptoms.

METHODS

A randomized controlled clinical trial with preintervention and postintervention measures was designed. The main outcome variable was negative psychotic symptoms assessed through the seven subscales of the Spanish version of the positive and negative syndrome scale. Data were analyzed using a repeated measures analysis of variance and reliable change index calculation.

RESULTS

There were no statistical differences between groups at the preintervention assessment. Statistically significant differences were found after MBI for the time in emotional withdrawal (F = 37.75, P < 0.001, η² = 0.437) and social withdrawal (F = 37.75, P < 0.001, η² = 0.437).

CONCLUSION

MBI added to IRT reduced the lack of interest and involvement with affective commitment to daily life activities, and interest and engagement in social activities increased. These negative psychotic symptoms were not improved by IRT alone.

Key Words: Mindfulness; Psychosis; Clinical trial; Emotional withdrawal; Social functioning; Schizophrenia

Core Tip: Mindfulness-based interventions when combined with integrated rehabilitation treatment significantly reduced emotional and social withdrawal in people with psychosis. These specific negative symptoms were not improved by integrated rehabilitation alone. This effect may be attributed to the role of mindfulness in fostering acceptance of psychotic experiences, enhancing emotional engagement, and promoting social interaction. The study highlights the potential for mindfulness as a valuable adjunct to rehabilitation treatment.

INTRODUCTION

Psychosis is a mental disorder characterized by both positive and negative symptomatology and impaired social functioning[1-3]. Positive symptoms entail an amplification or distortion of normal functions, including hallucinations, delusions, and disordered thinking. In contrast, negative symptoms refer to the reduction of a normal function affecting core domains for a person’s daily functioning, i.e. blunted affect, diminished emotional expression, anhedonia, or lack of interest in social affairs. Psychotic disorders also imply a high economic cost ranging between 0.02% and 1.65% of the gross domestic product in developed countries[4], making them among the most financially burdensome diagnoses. Negative symptoms are at the core of the impairment in daily life functioning, accounting for more than the 70% (indirect cost) of the total costs[5].

Positive symptoms have shown a favorable response to both antipsychotics and psychological interventions[1,6]. However, addressing negative symptoms remains an ongoing challenge[7]. The development of pharmacological treatments for negative symptoms has not progressed as swiftly as it has for positive symptoms[8], leading to various proposals for the future of pharmacological treatment research in psychoses[9]. On the other hand, psychosocial interventions have demonstrated a small to moderate effect and are well accepted by patients and their families. Among psychological therapies, cognitive behavioral therapy for psychosis has the most substantial evidence in its favor. However, according to a recent systematic review of meta-analyses[10], the effectiveness of cognitive behavioral therapy reducing negative symptoms was not superior to an active control condition in clinical trials. In contrast with cognitive behavioral therapy for psychosis, mindfulness-based interventions (MBIs) have been shown as a promising treatment option due to its effectiveness in reducing negative symptoms compared to active control conditions[11]. MBI also has a high patient acceptance rate[12].

MBIs applied to psychoses aim to foster acceptance rather than confronting the individual with psychotic experiences[13]. To do so MBIs help people experiencing psychotic experiences to remain in contact and react with acceptance rather than struggling or avoidance[14]. Therefore, the theoretical background is different from that of cognitive behavioral therapy for psychosis[15]. MBIs have shown positive findings enhancing the quality of life in people experiencing psychosis[16,17]. The improvement on quality of life is accounted for as a modification of the relationship with the content of positive symptoms[18] as well as for the mediation role of dispositional mindfulness between psychotic experiences and psychological well-being[19].

MBI also improves social cognition in psychotic disorders as shown by López-Navarro et al[20] and Mediavilla et al[21]. Although there are no crucial findings about the processes accountable for this effect, it has been suggested that mindfulness applied to psychosis enhances inhibitory control, which is a key cognitive process for social cognition[22]. A growing body of evidence suggests that MBIs are effective at reducing negative symptoms with effect sizes ranging from small to moderate[10,23-25]. However, in contrast with psychological quality of life or social cognition, the mechanism by which MBIs reduce negative symptoms remains unknown.

A common challenge in studying the effectiveness of interventions targeting negative symptoms is that they are grouped into one general category[9]. Therefore, to the best of our knowledge, no study has conducted a detailed assessment of the effects of MBIs on the different manifestations of negative symptoms. We reanalyzed data from a previous randomized controlled trial addressing the effects of mindfulness added to rehabilitation treatment of people diagnosed with severe mental illness to determine how mindfulness improves negative symptoms. The new analysis strategy sought to examine the effects of both treatments on negative symptoms.

MATERIALS AND METHODS

Study design

A randomized controlled clinical trial with preintervention and postintervention measures was designed for implementation in a naturalistic rehabilitation setting. There were two treatment arms: Integrated rehabilitation treatment (IRT); and IRT enhanced with MBI (IRT + MBI). The main outcome variable was negative psychotic symptoms. The trial was registered in the ISRCTN Registry (No. ISRCTN52873519). The study complied with the Declaration of Helsinki and was approved by the Research Ethics Committee of the University of Balearic Islands (No. 6163/1806/2015).

Participants

Participants were recruited from a community rehabilitation center in Spain. The study sample comprised a total of 52 randomized outpatients. The mean age of the sample was 39.71 ± 8.98 years with a mean duration of disorder of 14.13 ± 7.66 years. Most of the participants were male (78.8%), and the mean number of years of education was 12.04 ± 2.08. Participants were not employed and did not receive any financial compensation for their involvement in the research.

Eligibility criteria for participation included: (1) Age between 18 and 65 years; (2) Diagnosis of a psychotic disorder according to clinical record; (3) Stability in antipsychotic medication and absence of hospitalization in the preceding month; (4) Signed the informed consent; and (5) Proficiency in understanding and reading Spanish. Criteria for exclusion encompassed: (1) Significant cognitive deficits determined via clinical record or any medical condition that could potentially interfere with the outcomes of the intervention (e.g., dementia or stroke); (2) Inability to participate in mindfulness or rehabilitation treatment sessions; and (3) Refusal to engage in the study or to provide informed consent.

Instruments and procedure

The clinical and demographic characteristics of the sample were gathered using a structured record, which included information on age, sex, years since diagnosis, number of years of education, and clinical diagnosis. To assess the primary outcome variable, we used the Spanish version of the positive and negative syndrome scale (PANSS)[26]. The PANSS assesses symptom severity in people with psychosis. We focused on the seven indexes that conform the negative subscale: Blunted affect; emotional withdrawal; poor rapport; social withdrawal; difficulty in abstract thinking; lack of spontaneity and flow of conversation; and stereotyped thinking. Table 1 provides detailed information of the content included by each subscale.

Table 1 Definition of the positive and negative syndrome scale negative subscales.

PANSS negative subscale	Definition
Blunted affect	Diminished emotional responsiveness as characterized by a reduction in facial expression, modulation of feelings, and communicative gestures
Emotional withdrawal	Lack of interest in, involvement with, and affective commitment to life’s events
Poor rapport	Lack of interpersonal empathy, openness in conversation, and sense of closeness, interest, or involvement with the others
Social withdrawal	Diminished interest and initiative in social interactions due to passivity, apathy, anergy, or avolition. This leads to reduced interpersonal involvement and neglect of activities of daily living
Difficulty in abstract thinking	Impairment in the use of the abstract-symbolic mode of thinking, as evidenced by difficulty in classification, forming generalizations, and proceeding beyond concrete or egocentric thinking
Lack of spontaneity and flow of conversation	Reduction in the normal flow of communication associated with apathy, avolition, defensiveness, or cognitive deficit
Stereotyped thinking	Decreased fluidity, spontaneity, and flexibility of thinking, as evidenced in rigid, repetitious, or barren thought content

PANSS: Positive and negative syndrome scale.

To enhance external validity both the assessment and intervention protocols were naturally encompassed into the participants’ daily routines and the framework of a rehabilitation center within the public health system. A clinical psychologist from the center contacted potential participants to schedule an interview during which they received detailed information about the study and underwent an eligibility assessment. This session was designed to provide comprehensive information about the study and to evaluate their eligibility. Those considered eligible were then invited to participate.

Upon obtaining signed informed consent, each participant was assigned a randomization ID, which was documented in the clinical record form. A confidential master randomization list was maintained, accessible only to the principal investigator and the clinical team responsible for conducting the mindfulness sessions. The assessment of participants was carried out by a clinical psychologist who was not informed of the participants’ group assignments. Interviews were videotaped and scored at the end of the treatment arms by two clinical psychologists who were blinded to treatment allocation.

Following the assessment the last author assigned participants randomly by software to either the IRT group or the IRT + MBI group, ensuring that MBI groups maintained an optimal size of 8 to 12 participants. Randomization was conducted once a sufficient number of participants were available to start a mindfulness group (Figure 1). Data collection took place at the same community rehabilitation center, and missing data were handled using an intention-to-treat analysis.

Figure 1 CONSORT flowchart. IRT: Integrated rehabilitation treatment; MBI: Mindfulness-based intervention.

Intervention

There were two treatment arms: IRT and IRT + MBI. Both treatment arms were administered by clinical staff who were trained in rehabilitation strategies and treatment of people experiencing psychosis. Clinical staff also received additional training in mindfulness applications for psychosis for those involved in the IRT + MBI arm. The IRT arm spanned 26 weeks, with a focus on managing the intensity and frequency of psychotic symptoms, preventing relapses and hospitalizations, and enhancing social functioning. The program included 26 weekly group sessions, each lasting 1 h, that incorporated cognitive behavioral therapy techniques for symptom management, strategies for relapse prevention, and conflict resolution skills. Recognizing the mediating role of daily life stressors in the nexus between psychotic experiences and psychological well-being[27], IRT had a strong social skills training component.

The initial six sessions were dedicated to educating participants on the A-B-C model and elucidating the interconnections between feelings, thoughts, and the environment. The model consists of three components: A (activating event); B (beliefs); and C (consequences). The activating event refers to specific psychotic experiences, such as hearing voices or perceiving others as threatening. These symptoms often lead to beliefs that involve misinterpretations, such as “the voices are controlling me” or “people are planning to harm me”. These beliefs in turn result in consequences like distress, paranoia, or avoidance behaviors.

In sessions seven to nine, therapists worked collaboratively with individuals to identify real-life situations brought up by participants to exemplify the A-B-C model. Also, during these sessions, participants examined the evidence for and against their beliefs, explored alternative explanations, and reduced the automatic emotional or behavioral responses tied to their symptoms. The tenth to the sixteenth sessions focused on teaching social skills and assertiveness techniques, which were then applied in role-playing exercises during sessions seventeen to twenty. The concluding sessions, twenty-one to twenty-six, were aimed at applying problem-solving strategies to socially challenging situations identified by participants as distressing. In addition to the group sessions and to further prevent relapses and hospitalization, each participant underwent a weekly interview to review and adjust pharmacotherapy as needed. Unlike the MBI-enhanced arm, the standard IRT protocol did not include mindfulness training or family intervention components.

The IRT + MBI group was conducted alongside the 26-week rehabilitation program, integrating mindfulness practices following the framework established by López-Navarro et al[20]. To ensure adherence to the protocol, the last author monitored 80% of the sessions, verifying treatment fidelity. The mindfulness sessions aimed to change participants’ reactions to their own psychotic experiences, fostering an attitude of acceptance rather than resistance towards the experiences that could arise. The mindfulness training encouraged participants to recognize voices or thoughts for what they truly are rather than the content they convey.

Each mindfulness therapy session lasted for 60 min and was hosted in a facility provided at no cost by the local government. Sessions commenced with a period of habituation to the environment accompanied by calming music to recognize the role of physical sensations in grounding individuals in the present moment, especially within the context of psychosis. This was followed by a 10-min body awareness exercise, led by a psychologist trained in mindfulness. Subsequently, a 15-min guided meditation session was conducted by a psychiatrist and a clinical psychologist, both specializing in mindfulness and with experience in treating psychotic patients. Instruction during these sessions emphasized the cultivation of awareness and acceptance of various sensations, including bodily feelings, breath sensations, and any arising thoughts, images, or voices.

The goal was to encourage participants to observe and release engagement with the content of these experiences, including thoughts, voices, or other symptoms of psychosis and to refrain from judgement or criticism. The mindfulness sessions concluded with a 15-min period of reflective group discussion designed to deepen patients’ understanding and insights from the mindfulness exercises. To support continuous practice, participants were encouraged to engage in mindfulness exercises at home and were provided with an audio recording featuring the guided instructions from the sessions for home use.

Statistical analysis

Descriptive statistics were computed for the clinical and demographic characteristics of the overall sample and separately for each treatment group. Prior to analyzing the outcome variables, assumptions of normality and homoscedasticity were tested with the Shapiro-Wilk test and Levene’s test. Groups were compared at baseline in sociodemographic and clinical variables. We performed a repeated-measures analysis of variance (ANOVA) to test group differences on the PANSS negative subscales. If parametric assumptions were not met, a bootstrapped ANOVA was performed at 2000 iterations. Treatment condition (IRT vs IRT + MBI) was set as the between-subjects factor and time (pretreatment and post-treatment) as the within-subjects factor. Interaction components were analyzed using Bonferroni correction. If a statistically significant difference was detected, then reliable change index (RCI) was used to estimate the clinical change[28]. Data were analyzed with IBM SPSS 29 for Windows. Statistical significance was set at 0.05.

RESULTS

Fifty-two participants were recruited and randomly allocated to the IRT group or the IRT + MBI group. We found no statistically significant differences in demographic or clinical variables before treatment started. Table 2 shows detailed data about demographic and clinical features of the sample. Analysis of the parametric assumptions showed that none of the variables met normality. Before treatment started the scores on lack of spontaneity and flow of conversation (W = 4.42, P = 0.041) and stereotyped thinking (W = 5.97, P = 0.018) did not meet the homoscedasticity assumption. After treatment ended, the subscales that did not meet homoscedasticity were emotional withdrawal (W = 4.95, P = 0.031) and stereotyped thinking (W = 15.5, P < 0.001). Given the violation of the parametric assumptions all the analyses were bootstrapped. Participants on average attended 91.58% of the 26 mindfulness sessions, with attendance ranging from 21 to 26 sessions.

Table 2 Demographic and clinical features of the sample.

	Total sample (n = 52)	IRT (n = 26)	IRT + MBI (n = 26)	Statistics
Age, years	39.71 ± 8.98	40.15 ± 9.38	39.42 ± 6.33	t = 0.292, P = 0.771
Sex
Male	41 (78.8)	21 (80.8)	20 (76.9)	χ2 = 0.115, P = 0.734
Female	11 (21.2)	5 (19.2)	6 (23.1)
Years since diagnosis	14.13 ± 7.66	14.58 ± 8.22	13.69 ± 7.20	t = 0.413, P = 0.682
Education years	12.04 ± 2.08	11.93 ± 1.89	12.15 ± 2.25	t = -0.399, P = 0.691
Diagnosis
Paranoid schizophrenia	23 (44.2)	11 (42.3)	12 (43.2)	χ2 = 0.134, P = 0.999
Undifferentiated schizophrenia	8 (15.4)	4 (15.4)	8 (15.4)
Disorganized schizophrenia	4 (7.7)	2 (7.7)	2 (7.7)
Schizoaffective disorder	11 (21.2)	6 (23.1)	5 (19.2)
Bipolar disorder	4 (7.7)	2 (7.7)	2 (7.7)
Delusional disorder	2 (3.8)	1 (3.8)	1 (3.8)
PANSS
Positive	14.90 ± 5.80	14.69 ± 5.25	15.11 ± 6.40	t = -0.261, P = 0.796
Negative	19.08 ± 4.01	19.16 ± 4.01	19.00 ± 4.09	t = 0.137, P = 0.892
General	36.11 ± 8.61	36.50 ± 9.63	35.74 ± 7.64	t = 0.319, P = 0.751
Total	70.23 ± 15.46	70.85 ± 15.20	69.61 ± 15.90	t = 0.284, P = 0.777

Data are presented as n (%). IRT: Integrated rehabilitation treatment; MBI: Mindfulness-based intervention; PANSS: Positive and negative syndrome scale.

The repeated measures ANOVA on the PANSS negative subscales revealed no differences between groups at pretreatment. Main component analysis showed that there were statistically significant differences for the treatment factor in social withdrawal scores (F = 7.21, P = 0.01, η² = 0.126) but not for blunted affect (F = 0.67, P = 0.418, η² = 0.013), emotional withdrawal (F = 3.01, P = 0.089, η² = 0.057), poor rapport (F = 0.02, P = 0.88, η² < 0.001), difficulty in abstract thinking (F = 0.16, P = 0.692, η² = 0.003), lack of spontaneity and flow of conversation (F = 0.37, P = 0.544, η² = 0.007), or stereotyped thinking (F = 2.32, P = 0.134, η² = 0.044). We found statistically significant differences in emotional withdrawal (F = 37.75, P < 0.001, η² = 0.437), social withdrawal (F = 10.47, P < 0.001, η² = 0.264), difficulty in abstract thinking (F = 8.05, P = 0.007, η² = 0.139), and stereotyped thinking (F = 6.52, P = 0.014, η² = 0.115) for the time factor. However, we did not detect any statistically significant differences for blunted affect (F = 1.4, P = 0.242, η² = 0.027), poor rapport (F = 1.11, P = 0.297, η² = 0.022), and lack of spontaneity and flow of conversation (F = 0.48, P = 0.489, η² = 0.009). The interaction between factors was statistically significant for the scores on emotional withdrawal (F = 37.75, P < 0.001, η² = 0.437) and social withdrawal (F = 37.75, P < 0.001, η² = 0.437). Table 3 provides information about the ANOVA main component analyses.

Table 3 Repeated measures analysis of variance on subscales of the positive and negative syndrome scale negative scale.

PANSS negative subscale	Factor	F	P	η2
Blunted affect	Treatment	0.67	0.418	0.013
	Time	1.40	0.242	0.027
	Treatment x time	0.72	0.402	0.014
Emotional withdrawal	Treatment	3.01	0.089	0.057
	Time	38.75	< 0.001	0.437
	Treatment x time	25.67	< 0.001	0.339
Poor rapport	Treatment	0.02	0.880	< 0.001
	Time	1.11	0.297	0.022
	Treatment x time	0.12	0.727	0.002
Social withdrawal	Treatment	7.21	0.010	0.126
	Time	10.47	< 0.001	0.264
	Treatment x time	11.78	< 0.001	0.287
Difficulty in abstract thinking	Treatment	0.16	0.692	0.003
	Time	8.05	0.007	0.139
	Treatment x time	0.161	0.248	0.027
Lack of spontaneity and flow of conversation	Treatment	0.37	0.544	0.007
	Time	0.48	0.489	0.009
	Treatment x time	0.12	0.729	0.002
Stereotyped thinking	Treatment	2.32	0.134	0.044
	Time	6.52	0.014	0.115
	Treatment x time	0.01	0.999	< 0.001

PANSS: Positive and negative syndrome scale.

Bearing in mind that our main hypothesis was based on the interaction between factors, we analyzed the components of the interactions that reached statistical significance. Analysis of the time component revealed that the IRT + MBI group scored significantly lower at post-treatment in emotional withdrawal (F = 63.75, P < 0.001, η² = 0.56) and social withdrawal (F = 38.01, P < 0.001, η² = 0.432) compared with the IRT group. Analysis of the treatment component of the interaction showed that the IRT + MBI group scored significantly lower than the IRT group in emotional withdrawal (F = 14.89, P < 0.001, η² = 0.23) and social withdrawal (F = 22.2, P < 0.001, η² = 0.307). Table 4 provides detailed information about the complete ANOVA as well as descriptive statistics for each of the above analyses.

Table 4 Analysis of the interaction components of the repeated measures analysis of variance on subscales of the positive and negative syndrome scale negative.

PANSS negative subscale		PRE	POST	F	P	η2
Blunted affect	IRT	2.54 (1.03)	2.77 (0.99)	2.06	0.157	0.039
	IRT + MBI	2.42 (0.94)	2.46 (1.10)	0.06	0.812	0.001
	PRE			0.18	0.296	0.004
	POST			1.12	0.296	0.022
Emotional withdrawal	IRT	3.85 (1.12)	3.69 (1.32)	0.67	0.417	0.013
	IRT + MBI	4.00 (1.36)	2.50 (0.86)	63.75	< 0.001	0.560
	PRE			0.19	0.658	0.004
	POST			14.89	< 0.001	0.230
Poor rapport	IRT	2.38 (0.80)	2.46 (0.90)	0.25	0.622	0.005
	IRT + MBI	2.31 (1.09)	2.46 (1.14)	0.98	0.326	0.019
	PRE			0.08	0.773	0.002
	POST			0.01	0.999	< 0.001
Social withdrawal	IRT	4.08 (1.20)	4.12 (1.24)	0.03	0.857	0.001
	IRT + MBI	3.96 (1.31)	2.65 (0.98)	38.01	< 0.001	0.432
	PRE			0.11	0.742	0.002
	POST			22.20	< 0.001	0.307
Difficulty in abstract thinking	IRT	2.73 (1.18)	2.54 (1.27)	1.39	0.243	0.027
	IRT + MBI	2.73 (1.48)	2.27 (1.18)	8.03	0.007	0.138
	PRE			0.01	0.999	< 0.001
	POST			0.62	0.434	0.012
Lack of spontaneity and flow of conversation	IRT	2.31 (0.88)	2.19 (0.85)	0.55	0.463	0.011
	IRT + MBI	2.42 (1.14)	2.38 (1.06)	0.06	0.806	0.001
	PRE			0.17	0.685	0.003
	POST			0.52	0.474	0.010
Stereotyped thinking	IRT	1.31 (0.55)	1.19 (0.40)	3.26	0.077	0.061
	IRT + MBI	1.15 (0.67)	1.04 (0.20)	3.25	0.078	0.061
	PRE			1.41	0.241	0.027
	POST			3.08	0.086	0.058

Data are presented as n (%). The IRT and IRT + MBI rows show the interaction analysis for the time factor (within subjects). The PRE and POST rows show the interaction analysis for the treatment factor (between subjects). PANSS: Positive and negative syndrome scale; PRE: Pretreatment; POST: Post-treatment; IRT: Integrated rehabilitation treatment; MBI: Mindfulness-based intervention.

RCI estimation for emotional withdrawal scores revealed that 13 out of 26 participants in the IRT + MBI group and 3 out of 26 in the IRT group showed a reliable change, with a statistically significant difference between groups (χ² = 9.691, P = 0.002). Similarly, RCI estimation on social withdrawal scores found that 5 out of 26 in the IRT group exhibited a reliable change as did 13 out of 26 in the IRT + MBI group. This difference between groups on the RCI estimation was found statistically significant (χ² = 5.438, P = 0.02).

DISCUSSION

The main finding of our study was that mindfulness added to standard rehabilitation treatment improved emotional and social withdrawal in people experiencing psychosis. Also, we found that the improvement was superior in patients allocated to the mindfulness group than those allocated to rehabilitation treatment alone. Participants allocated to the IRT + MBI group improved their scores on emotional withdrawal compared to those allocated to IRT alone. This finding was similar to prior research about the beneficial effects of mindfulness on emotion regulation[29,30]. The improvement on emotional withdrawal can be accounted to teaching how to “let go” of the psychotic experiences instead of reacting with avoidance or struggle. This is a core component of mindfulness applied to psychosis[15,17,31] and a fundamental difference with the IRT intervention implemented in our study.

A prior study based on focus groups and grounded theory analysis[32] reported that accepting psychotic sensations is a therapeutic process central to mindfulness interventions that help patients to release self-defeating reactions and increase insight[14]. As shown by López-Navarro and Al-Halabí[33], this attitude is generalized to other contexts. Therefore, participants in the IRT + MBI group could develop an increased interest and involvement with daily-life events resulting in a reduction of their emotional withdrawal.

Our study also found that participants in the IRT + MBI group reduced their scores on social withdrawal when treatment ended, and this reduction was superior to the IRT group. This suggests that participants attending mindfulness sessions not only increased their interest and initiative in social interaction but also enhanced their involvement in social activities. This effect may be attributed to the effect of mindfulness on oneself[34] as well as to the dynamic nature of the self, which is constructed and modified through interactive social engagements[35,36].

Mindfulness for psychosis primarily focuses on developing and embracing a new perception of self. Initially, people with psychosis often view themselves negatively and are influenced by overpowering voices, negative beliefs, and previous traumas, leading to feelings of being inherently bad, inadequate, and worthless[37]. Through regular practice of mindfulness tailored to psychotic experiences, people begin to understand that their identity is not solely defined by their psychosis. This realization fosters the emergence of a new self-concept that is both balanced by acknowledging both positive and negative aspects and dynamic with the capability to change[38]. Ultimately, this new self facilitates conditions for more frequent and engaged interactions within an individual’s social context. This potential explanation is convergent with prior research attesting the relationship between mindfulness practice and improved social interaction[39,40].

It is important to note that we found no statistically significant effect of MBI combined with IRT on certain dimensions of negative symptoms, such as blunted affect, poor rapport, difficulty in abstract thinking, lack of spontaneity and flow of conversation, and stereotyped thinking. The lack of effect may be attributed to differences in the underlying mechanisms of these symptoms[41]. While MBIs are particularly effective in addressing motivational deficits by enhancing present moment awareness, emotional engagement, and social participation[42], expressive deficits and cognitive impairments may require more targeted interventions. Dimensions like blunted affect and poor rapport, which involve verbal and non-verbal expressive behaviors, might benefit from interventions explicitly focused on communication training. Similarly, symptoms such as difficulty in abstract thinking and stereotyped thinking, which are tied to cognitive rigidity, may respond better to cognitive remediation or interventions aimed at improving executive functioning.

Furthermore, the intervention did not involve the families of participants, who often play a crucial role in the recovery process and are significantly affected by the diagnosis of psychosis[43]. Integrating family-focused approaches could provide a more supportive environment for comprehensively addressing negative symptoms[44]. Additionally, the duration and intensity of the intervention in the present study may not have been sufficient to induce significant changes in more entrenched or complex symptoms. These findings highlight the need for future research to explore complementary or alternative approaches tailored to address the full spectrum of negative symptoms in psychosis[45].

The clinical relevance of these findings is highlighted by providing the first data on how the combination of IRT with mindfulness reduces negative psychotic symptoms, specifically by decreasing emotional and social withdrawal. Moreover, our study was conducted in a real-world setting that increases the external validity of the findings. The findings contribute to the design and optimization of treatment strategies for people with psychosis. Individuals exhibiting greater social and emotional withdrawal may potentially benefit to a greater extent from the inclusion of mindfulness in their rehabilitation treatment. Finally, our findings lend further support to the idea that integrating MBI with rehabilitation treatment for psychosis represents a promising approach for enhancing recovery in this client group.

Our study has strengths and limitations that deserve mention. The main strengths of the study were the use of a randomized controlled trial design, the use of well-validated measurement instruments, the use of a reliable assessment process through videotaped clinical interviews to tap negative symptom manifestations, and the interventions integrated with daily routines of the rehabilitation center. The main limitation was the sample size, which may limit the generalization of the findings, although it was enough to test the main hypothesis. Furthermore, the sample was disproportionately male. While that is reflective of the epidemiological prevalence of psychotic disorders in Spain, it could influence the outcomes. Also, home practice was not measured, which may compromise the interpretation of the findings as it may moderate the effect of the interventions. Additionally, we did not measure the long-term effects of the intervention. Further research should address these limitations and evaluate the cost-effectiveness of both treatment arms. Also, future research should study the influence of moderate variables like social stigma and the effect of mindfulness on the family and caregivers of people receiving rehabilitation treatment[46].

CONCLUSION

Our study was the first to provide detailed data on the specific effects of incorporating mindfulness into rehabilitation treatment on each component of negative psychotic symptoms. Several studies have shown that MBIs reduce negative psychotic symptoms. Our study extended these findings by identifying a reduction in social and emotional withdrawal as key factors contributing to this decrease in negative psychotic symptoms. Furthermore, our results highlighted the combination of rehabilitation treatment with MBIs is more effective in reducing negative symptoms than rehabilitation treatment alone. The clinical relevance of our findings lies in the potential to optimize rehabilitation treatment for people experiencing psychosis and enhance their recovery.

ACKNOWLEDGEMENTS

We are very grateful to all the patients who took part in this study. Also, we thank all the health professionals that provide us with administrative support. We would also like to express our gratitude to Dr. Guido Corradi for his review of the statistical procedures implemented.