The association between eating disorders and psychosis in clinical and non-clinical populations: a systematic review and meta-analysis

Background: Eating disorders and psychotic disorders represent two of the most serious psychiatric conditions. Emerging lines of evidence from genetic and epidemiological studies suggest that these disorders may commonly co-occur. This systematic review investigated the association between these disorders across community and clinical populations. Method: A systematic review was preregistered (CRD42021231771) and conducted according to PRISMA guidelines. Web of Science, PsycINFO and Medline were searched for articles on the association and comorbidity between psychosis and eating disorders up to the 26th February 2024. Meta-analysis was conducted using a random effects model for studies reporting comorbidity of eating disorders and psychotic disorders based on clinical diagnosis or interview measures. A narrative synthesis was conducted for all other studies and grouped by sample (general population, eating disorders or psychotic disorders). Results: In total 43 studies met inclusion criteria for the systematic review and 18 were included in the meta-analysis. Findings suggest substantial comorbidity between eating disorders and psychotic disorders, with a pooled comorbidity prevalence of 8% (CI: 4, 14) based on clinical diagnosis or interview measures. Studies using self-report questionnaires also highlight the association between eating disorders and psychosis across clinical and community populations. Data from prospective studies in community population suggest that psychotic symptoms can precede eating pathology. Conclusions: Eating disorders and psychotic disorders frequently co-occur. Further research should investigate the temporal order of symptom development and consider the need for novel interventions targeted at overlapping psychotic and eating disorder symptoms and associated phenomena.