Association Between Cannabis and Psychosis: Epidemiologic Evidence

Biol Psychiatry. 2016 Apr 1;79(7):549-56. doi: 10.1016/j.biopsych.2015.08.001. Epub 2015 Aug 12.


Associations between cannabis use and psychotic outcomes are consistently reported, but establishing causality from observational designs can be problematic. We review the evidence from longitudinal studies that have examined this relationship and discuss the epidemiologic evidence for and against interpreting the findings as causal. We also review the evidence identifying groups at particularly high risk of developing psychosis from using cannabis. Overall, evidence from epidemiologic studies provides strong enough evidence to warrant a public health message that cannabis use can increase the risk of psychotic disorders. However, further studies are required to determine the magnitude of this effect, to determine the effect of different strains of cannabis on risk, and to identify high-risk groups particularly susceptible to the effects of cannabis on psychosis. We also discuss complementary epidemiologic methods that can help address these questions.

Keywords: Cannabis; Epidemiology; Longitudinal studies; Marijuana; Psychosis; Schizophrenia.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Cannabinoids / adverse effects*
  • Cannabinoids / pharmacology
  • Cannabis / adverse effects*
  • Humans
  • Marijuana Abuse / psychology*
  • Marijuana Smoking / psychology*
  • Meta-Analysis as Topic
  • Psychoses, Substance-Induced / epidemiology*
  • Randomized Controlled Trials as Topic
  • Risk Factors


  • Cannabinoids