Substance use disorders in schizophrenia: Review, integration, and a proposed model

Substance use disorders occur in approximately 40 to 50% of individuals wit h schizophrenia. Clinically, substance use disorders are associated with a variety of negative out-comes in schizophrenia, including incarceration, ho melessness, violence, and suicide. An understanding of the reasons for such high rates of substance use disorders may yield insights into the treatmen t of this comorbidity in schizophrenia. This review summarizes methodologic al and conceptual issues concerning the study of substance use disorders in schizophrenia and provides a review of the prevalence of this co-occurrenc e. Prevailing theories regarding the co-occurrence of schizophrenia and sub stance use disorders are reviewed. Little empirical support is found for mo dels suggesting that schizophrenic symptoms lead to substance use (self-med ication), that substance use lends to schizophrenia, or that there is a gen etic relationship between schizophrenia and sub stance use. An integrative affect-regulation model incorporating individual differences in traits and responses to stress is proposed for future study. (C) 2000 Elsevier Science Ltd.