Illicit substance use and its correlates in first episode psychosis.

Abstract

To determine if substance use (particularly cannabis) is more frequent among first episode psychosis patients and associated with a more problematic clinical presentation.

All first episode psychosis (FEP) patients presenting to secondary services were recruited from London and Nottingham, over 2 years, in the Aetiology and Ethnicity of Schizophrenia and Other Psychoses study broad framework. Clinical and sociodemographic variables were assessed using a set of standardized instruments. A schedule was created to retrospectively collate substance use data from patients, relatives and clinicians.

Five hundred and eleven FEP were identified. They used three to five times more substances than general population. Substance use was associated with poorer social adjustment and a more acute mode of onset. Cannabis use did not affect social adjustment, but was associated with a more acute mode of onset.

Cannabis has a different impact on FEP than other substances. Large epidemiological studies are needed to disentangle cannabis effect.