Cannabis use and first-episode psychosis: relationship with manic and psychotic symptoms, and with age at presentation
Psychological Medicine May 24, 2013 James Stone, Helen L. Fisher, Barnaby Major et al. 69 citations
Cannabis use is linked to an earlier onset of psychosis and more severe manic symptoms and conceptual disorganization, but not to delusions, hallucinations, negative symptoms, or daily functioning. In a naturalistic cohort of 502 patients with first-episode psychosis assessed at entry to services and after one year, those who reduced or stopped cannabis use showed the greatest improvement in symptoms, while continued users remained more symptomatic than non-users. Effective interventions to reduce cannabis use could yield significant health benefits for this population.