Some research suggests that marijuana smokers are diagnosed with depression more often than nonsmokers are — particularly regular or heavy marijuana users. However, it doesn't appear that marijuana directly causes depression.
It's likely that the genetic, environmental or other factors that trigger depression also lead to marijuana use. Some people with depression may use marijuana as a way to detach from their depressive symptoms. Heavy users may appear depressed as a result of the dulling effects of the drug on feelings and emotions.
There also are links between marijuana and other mental health conditions. Marijuana use may trigger schizophrenia or detachment from reality (psychosis) in people who are at higher risk of psychosis. The symptoms of diagnosed psychotic illness may be aggravated if marijuana use continues.
There also is some evidence that teenagers who attempt suicide may be more likely to have used marijuana than those who have not made an attempt. As with marijuana use and depression, more research is needed to better understand these associations.
The bottom line: Marijuana use and depression accompany each other more often than you might expect by chance, but there's no clear evidence that marijuana directly causes depression.
Nov. 06, 2015
- Cannabis and mental health. Royal College of Psychiatrists. http://www.rcpsych.ac.uk/healthadvice/problemsdisorders/cannabis.aspx. Accessed Oct. 12, 2015.
- Is there a link between marijuana use and mental illness? National Institute on Drug Abuse. https://www.drugabuse.gov/publications/research-reports/marijuana/there-link-between-marijuana-use-mental-illness. Accessed Oct. 12, 2015.
- Grunberg VA, et al. Can marijuana make it better? Prospective effects of marijuana and temperament on risk for anxiety and depression. Psychology of Addictive Behaviors. 2015;29:590.
- Feingold D, et al. The association between cannabis use and mood disorders: A longitudinal study. Journal of Affective Disorders. 2015;172:211.
- Lev-Ran S, et al. The association between cannabis use and depression: A systematic review and meta-analysis of longitudinal studies. Psychological Medicine. 2014;44:797.
- Delforterie MJ, et al. The relationship between cannabis involvement and suicidal thoughts and behaviors. Drug and Alcohol Dependence. 2015;150:98.
- Bechtold J, et al. Chronic adolescent marijuana use as a risk factor for physical and mental health problems in young adult men. Psychology of Addictive Behaviors. 2015;29:552.
- Volkow ND, et al. Adverse health effects of marijuana use. New England Journal of Medicine. 2014;370:2219.
- Bostwick JM (expert opinion). Mayo Clinic, Rochester, Minn. Oct. 20, 2015.