Cannabis and mental illness: a review

Eur Arch Psychiatry Clin Neurosci. 2019 Feb;269(1):107-120. doi: 10.1007/s00406-018-0970-7. Epub 2018 Dec 19.


With the increasing push to legalize cannabis in Western nations, there is a need to gage the potential impact of this policy change on vulnerable populations, such as those with mental illness, including schizophrenia, mood, and anxiety disorders. This is particularly important as there are strong motives in these individuals to seek short-term reward (e.g., "getting high"). Nonetheless, data to support the beneficial effects of cannabis use in psychiatric populations are limited, and potential harms in patients with psychotic and mood disorders have been increasingly documented. This article reviews the effects of cannabis in people with mental illness. Then, we provide a reconciliation of the addiction vulnerability and allostatic hypotheses to explain co-morbidity addiction in mentally ill cannabis users, as well as to further aid in developing a rational framework for the assessment and treatment of problematic cannabis use in these patients.

Keywords: Addiction; Anxiety disorders; Cannabis; Harms; Legalization; Mood disorders; Post-traumatic stress disorder; Schizophrenia; Therapeutics.

Publication types

  • Review

MeSH terms

  • Anxiety Disorders / chemically induced
  • Anxiety Disorders / drug therapy*
  • Bipolar Disorder / chemically induced
  • Bipolar Disorder / drug therapy*
  • Cannabinoids / adverse effects
  • Cannabinoids / pharmacology*
  • Depressive Disorder, Major / chemically induced
  • Depressive Disorder, Major / drug therapy*
  • Humans
  • Marijuana Use / adverse effects*
  • Schizophrenia / chemically induced
  • Schizophrenia / drug therapy*
  • Stress Disorders, Post-Traumatic / chemically induced
  • Stress Disorders, Post-Traumatic / drug therapy*


  • Cannabinoids