Epidemiological analysis of alcohol and drug use as risk factors for psychotic experiences.

Clinical and laboratory studies link alcohol and other drug use to the occurrence of psychotic experiences, but epidemiologic evidence has been lacking. In this study, the quantitative relationships between alcohol or other drug use and psychotic experiences were examined by analysis of prospective data from 4994 adult household residents sampled in a multisite survey of mental disorders in the population, the NIMH Epidemiologic Catchment Area Program. After control for sociodemographic factors and preexisting psychiatric conditions, the risk for onset of self-reported delusions or hallucinations was observed to be greater for daily users of marijuana or cocaine and for users of anxiolytics or sympathomimetics compared with nonusers. After control for daily cocaine use and alcohol disorder, the risk of onset of psychotic experiences for daily users of marijuana was double that for nonusers. Alcohol disorder in men was associated with eightfold risk and in women with threefold risk. Baseline depressive episodes, manic episodes, agoraphobia, and obsessive-compulsive disorder also were associated with increased risk of onset of psychotic experiences.