Association Between Continued Cannabis Use and Risk of Relapse in First-Episode Psychosis

Using a quasi-experimental design wherein we assessed cannabis use patterns after the onset of psychosis, we were able to investigate the causal nature of the association between cannabis use and risk of relapse in psychosis. Although it has been proposed that a common genetic liability or reverse causation may underlie the association between continued cannabis use and relapse,13 our results indicate that change in cannabis use represents a robust risk factor for relapse in patients with FEP.