Background: Substance misuse is a significant problem in schizophrenia. The purpose of this study was to examine the prevalence and correlates of substance misuse in individuals with a first episode of psychosis at the time they first present for treatment.
Method: The first 357 consecutive admissions to a comprehensive early psychosis program were included. Assessment measures were the Positive and Negative Syndrome Scale, the Calgary Depression Scale for Schizophrenia, the Quality of Life Scale, the Case Manager Rating Scale and the Premorbid Adjustment Scale.
Results: Forty-four percent of the sample, the majority of whom used alcohol or cannabis, met diagnostic criteria for substance abuse/dependence. The prevalence was significantly higher than in the general population. Substance misuse was significantly associated with male gender, young age and age of onset.
Conclusions: This study confirms the high rates of substance misuse, in particular cannabis, in first-episode psychosis. Implications for treatment are addressed.