The Association between Autism and Psychosis and the Tools Used to Measure it: An Updated Systematic Review and Meta-Analysis

Objectives: Autistic individuals are more likely to be diagnosed with psychotic disorders and experience psychotic symptoms. This association may result from methodological issues, such as misinterpretation of psychosis questionnaires by autistic individuals and clinician difficulty differentiating between symptoms of autism and psychosis. This meta-analysis aimed to update the review of this association and examine whether it is moderated by the methods used to measure it. Methods: A systematic literature search was conducted in PsycINFO, MEDLINE, CINAHL, Embase, and Web of Science. Included studies required: autism and psychosis measurements, comorbidity data, adult participants, and quantitative data. Risk of bias was assessed using Hoy et al. (2012) criteria, and analyses examined correlational data, computed odds ratios, and computed Cohen's d. Results: Sixty-three papers were included. Significant correlations were found between autistic traits and overall (r = 0.435, p .0001), positive (r = .274, p .0001), negative (r = .506, p .0001), and disorganized (r = .366, p .0001) psychotic symptoms. Individuals with one condition had increased risk of being diagnosed with the other (OR = 7.03, p .001), and scored higher on trait measures of the other (d = 1.187, p .0001). No moderating effect of measurement was found. Discussion: This meta-analysis provides an updated overview of the association between autism and psychosis, with no evidence that methodological issues are specific to any measure. The weaker correlation between autistic traits and positive psychotic symptoms suggests symptom overlap may partly explain the association.