Autism spectrum disorder and personality disorders: Comorbidity and differential diagnosis

Table 1 Description of the studies included in the systematic review

Ref.	Setting	Aim	Statistical methods	Limitations
Soderstrom et al[50], 2002	NeuropsychiatricClinic in Sweden	To study the personality characteristics of adults with AS	One sample t-test	Small sample size
Anckarsäter et al[47], 2006	Neuropsychiatric Clinic in Sweden	To describe PD in relations to ADHD and ASD symptoms	One sample t - test	Non-specific symptoms may be overselected
Ketelaars et al[43], 2008	Center of Expertise for Autism in Netherlands	To explore difference between patients with mild ASD and patients without ASD in term of AQ scores and psychiatric comorbidity	Χ2 test	Small sample size
Rydén and Bejerot[40], 2008	Psychiatric setting (tertiary unit) in Sweden	To characterize psychiatric patients with ASD in regard to demographical factors, psychiatric comorbidity and personality traits and compare the ASD group with a psychiatric control group; to compare differences of personality traits between females and males in the ASD group.	Fisher exact test; t-test; Kruskal-Wallis test	Not ADOS/ADI-R for assessing ASD; A naturalistic study
Hofvander et al[14], 2009	Neuropsychiatric Hospital in France NeuropsychiatricClinic in Sweden	To describe the clinical presentation and psychosocial outcome of a group of normal intelligence adults with ASD	Χ2 test	Lack of comparison group; Two studies sites; Prevalence of comorbid psychiatric conditions may be overestimated
Sizoo et al[49], 2009	Two diagnostic centers specialized for adult patients with developmental disorders in Netherlands	To test whether adults with ASD or ADHD have distinct personality profiles, to assess how personality profiles in these groups differed by SUD status	One sample t-test	The clinically based diagnostic procedures; The absence of a psychiatric control group; All participants were diagnosed in adulthood
Geurts and Jansen[44], 2011	Tertiary psychiatric unit from diagnosing ASD in Netherlands	To draw the pathway to a diagnosis for adults referred to ASD assessment	Mann-Whitney U tests; Kruskal-Wallis tests; Χ2 test	Retrospective chart study; Not standardized clinical interviews for assessing axis I and axis II diagnosis
Kanai et al[59], 2011	University Hospital in Japan	To examine the clinical characteristics of adults with AS	Spearman’s rank correlation coefficient	Small sample size
Kanai et al[67], 2011	University Hospital in Japan	To examine the clinical characteristics of adults with AS	Mann-Whitney U test	Small sample size
Lugnegård et al[38], 2012	Neuropsychiatric clinics in Sweden	To explore the presence of PD in young adults with AS	Χ2 test	Small sample size
Schriber et al[55], 2014	Local recruitment by physicians, psychologists, speech and language pathologists, occupational therapists, advocacy groups, regional centers, ASD support groups in United States	To compare self-reports of Big Five personality traits in adults with ASD to those of typically developing adults.	Independent sample t-test	Small sample size
Hesselmark et al[62], 2015	Tertiary psychiatric unit for diagnosing ASD; a community based facility for ASD; a website for ASD	To test validity and reliability of self-report data using the NEO-PI-R in adults with ASD	Independent sample t-test	Small sample size
Strunz et al[26], 2015	Department of Psychiatry at a University Hospital in Germany	To identify personality traits in adults with ASD and to differentiate them from patients with NPD, BPD and NCC	MANOVA	Selection bias (BPD and NPD were inpatients, while ASD were outpatients)
Helles et al[52], 2016	Neuropsychiatric Centre in Sweden	To examine temperament and character in males who were diagnosed with AS in childhood and followed prospectively over almost two decades	t-test; Kruskal-Wallis H testDunn’s post hoc test	Only men with AS
Schwartzman et al[56], 2016	On line recruitment United States	To assess and compare personality traits of adults with and without elevated ASD traits using; the Five Factor Model of personality	Independent sample t-test	Online administration of self-report questionnaires; Sample was not representative of adult population with ASD
Vuijk et al[51], 2018	Expertise Centre for Autism in Netherland	To investigated temperament and character dimensions of men with ASD by individual case matching to a comparison group.	t-test	Only men with ASD
Ozonoff et al[65], 2005	University Child and Adolescent specialized clinic in United States	To explore personality and psychopathology in adult with ASD	Independent sample t-test	Small sample size
López-Pérez et al[95], 2017	Four different mental health institutions in Spain	To examine use of different interpersonal ER strategies in BPD and AS compared to normative control participants	ANOVA	Self-reports of interpersonal ER; ToM was not assessed
Dudas et al[92], 2017	CARD, online responders to a website	To compare ASC, BPD, and comorbid patients in terms of autistic traits, empathy, and systemizing	ANOVA	Diagnosis was based on self-report of patients
Murphy[100], 2006	High security psychiatric care in UK	To compare the ToM performance of three forensic patient groups (AS, Schizophrenia and PD patients)	Kruskal-Wallis H test	No control for the potential influence of medication on cognitive functioning
Stanfield et al[87], 2017	Clinical and support services in Scotland; Nonpsychotic people who had previously participated in the EHRS of schizophrenia	To compare Social Cognition in ASD and SPD using functional magnetic resonance imaging (fMRI).	Kruskal- Wallis tests	Small sample size
Booules-Katri et al[84], 2019	Patients and relatives of schizophrenia patients attending psychiatric service at a hospital in Spain; Public advertisements	To compare the ToM performance of a group of HFA and SSPD with a matched HC group	t-test	SSPD sample consisted of non-clinical individuals

ADHD: Attention deficit hyperactivity disorder; ADI-R: Autism diagnostic interview - revised; ADOS: Autism diagnostic observation schedule-generic; AQ: Autism quotient; AS: Asperger Syndrome; ASC: Autism spectrum condition; ASD: Autism spectrum disorder; BPD: Borderline personality disorder; Er: emotion regulation; HC: Health control; HFA: High-functioning autism; NCC: Non-clinical controls; NEO-PI-R: NEO personality inventory revised; NPD: Narcissistic personality disorder; PD: Personality disorder; SPD: Schizotypal personality disorder; SSPD: Schizotypal-schizoid personality disorder; SUD: Substance use disorder; ToM: Theory of mind.