Diagnostic and demographic correlates of substance abuse in schizophrenia and major affective disorder.

The relationship between history of specific types of substance abuse (alcohol, stimulants, cannabis, hallucinogens, narcotics) and demographic and diagnostic variables was evaluated in a large (n = 263) sample of schizophrenic, schizoaffective, major depression and bipolar disorder patients. Prevalence rates were also compared with rates observed in a previous study (1983-1986) conducted using the same methods. Demographic characteristics (gender, age, race, educational level) were strong predictors of type of substance abuse. Patients with a history of cocaine abuse had fewer prior hospitalizations, suggesting that less impaired psychiatric patients may be more prone to illicit substance abuse. Diagnoses were not related to most types of substance abuse, although there was a trend for bipolar patients to have a history of alcohol abuse. The results demonstrate the importance of matching groups on demographic characteristics when exploring diagnostic differences in preference to abuse specific types of substances.