Substance Use and Incidence of Psychosis Diagnoses Among Gay, Bisexual, and Other Men Who Have Sex with Men Compared with Males from the General Population: A Matched Cohort Study from Metro Vancouver, Canada

BACKGROUND: Gay, bisexual, and other men who have sex with men (GBM) report higher use of psychoactive substances, which may contribute to many adverse outcomes. METHOD: We examined the incidence of psychosis and associated substance use among GBM compared with males from the general male population. We analyzed data from 798 sexually active GBM from two cohort studies based in Vancouver, Canada, linking their survey data to administrative health records. We matched GBM (1:5) by age and geography to HIV-negative males. We determined incident psychosis using ICD-9/10 codes and examined associated factors using Poisson regression. RESULTS: Incidence was 1.74 per 100 person-years for GBM and 0.64 for their matches (risk-ratio = 2.71; 95% CI:1.95-3.78). Among GBM, opioid use, living with HIV, unstable housing, and anxiety symptoms were independently associated with psychosis. CONCLUSIONS: Addressing social determinants of health for GBM such as unstable housing, particularly among those living with HIV, may reduce the burden of substance-use associated psychosis.