Heavy Episodic Drinking and Frequent Marijuana Use Can Cause Depressive Symptoms In Adolescents

The relationship between substance use and depression is complex, with substance use thought both to cause depressive symptoms (“stress model”) and relieve them (“self-medication model”). Researchers used data from the National Longitudinal Study of Adolescent to Adult Health to investigate both pathways across age and sex. The authors found:

• Heavy episodic drinking (defined as consuming ≥5 drinks on an occasion) and marijuana use increase from adolescence to adulthood, and then decrease in early adulthood. Conversely, depressive symptoms decrease in the transition to adulthood and increase in early adulthood
• There is a significant positive association between depressive symptoms in adolescence and increasing frequency of marijuana use from adolescence to adulthood in both genders, supporting the self-medication model.
• Persistent heavy episodic drinking or marijuana use are concurrently positively associated with depressive symptoms, supporting the stress model, especially for females.

Comments: Adolescents may use marijuana to self-medicate depressive symptoms, although persistent use during adolescence is associated with more depressive symptoms, especially in girls. Heavy episodic drinking is associated with more depressive symptoms, and does not appear to be used as a form of self-medication. These results emphasize the importance of concurrent screening for substance use and depressive symptoms, especially among young people with marijuana use. People with heavy episodic drinking and those with heavy marijuana use should be advised of the risk of depression related to use.

Sharon Levy, MD, MPH

Reference: Wilkinson AL, Halpern CT, Herring AH, et al. Testing longitudinal relationships between binge drinking, marijuana use, and depressive symptoms and moderation by sex. J Adolesc Health. 2016;59(6), 681–687.