Association of cannabis use in adolescence and risk of depression, anxiety, and suicidality in young adulthood. A systematic review and meta-analysis.

JAMA Psychiatry

Adolescents who use cannabis regularly are more likely to experience depression in young adulthood. This is the main finding from an analysis that combined the results from 7 different studies that measured cannabis use before 18 years of age and then tested the same people for depression when they were between 18-32 years of age.

About 8% of adults in the United States have depression at any given time. That rate is increased to somewhere between 9-12% for people who regularly used cannabis during adolescence, the study found. This small increase in likelihood may or may not bother individuals. At a population level, however, it can account for 400,000 cases of depression in the United States and around 30,000 in Canada.

The researchers also found that adolescent cannabis users had somewhere between 1.1-2 times higher odds of having suicidal thoughts and between 1.5-7.8 times higher odds of attempting suicide, compared to non-users. The impact of adolescent cannabis use on anxiety in young adulthood was unclear. It might increase the odds of having anxiety by about 20%.

This study accounted for depression at baseline—which removes the possibility that the results could be driven by depression causing cannabis use (rather than the other way around: cannabis use causing depression). The analysis does not rule out, however, all confounding factors. Another factor may drive both cannabis use during adolescence and depression in young adulthood. Causality has yet to be securely established.

For the original article, click here.

Gobbi, G., et al. (2019). Association of cannabis use in adolescence and risk of depression, anxiety, and suicidality in young adulthood. A systematic review and meta-analysis. JAMA Psychiatry, Volume 76 (Issue 4), pp. 426-434. DOI:10.1001/jamapsychiatry.2018.4500