LAUSR

Abstract Background Comorbidity between obsessive compulsive disorder (OCD) and psychotic disorders has long been a subject of interest and speculation, with much overlap being reported. The current review seeks to: (1) Investigate the prevalence of co-occurring OCD and psychosis, reporting pooled prevalence rates; and (2) Explore variability in reported rates on the basis of categorical and/or dimensional classifications of OCD and psychosis and (3) explore potential moderators of variability. Method A systematic search was performed of key databases (Embase, PSYCHInfo, MEDLINE, Scopus) from January 1988 to October 2017. Included in the meta-analyses were studies that reported adult (18+) prevalence of comorbid OCD, obsessional compulsive symptoms (OCS) and psychosis-related disorders. Results 94 articles with 103 effect sizes were extracted. Overall, when using categorical diagnoses, the prevalence rate of comorbid OCD and psychotic disorder was 12% (n = 155649; k = 81; 95% CI = 9–15%). Using diagnostic plus symptom criteria, the prevalence was 24% (n = 9563; k = 46, 95% CI = 20–28%). Conclusion Given the substantial co-occurrence, it is important that individuals presenting in routine clinical practice are assessed for both disorders. To advance understanding, future research must go beyond comorbidity to explore latent dimensions that may account for their development and/or maintenance (e.g., trauma).