Early age cannabis use and depression link
Cannabis is the most commonly used drug of abuse by adolescents in the world, particularly boys. While the impact of adolescent cannabis use on the development of psychosis has been investigated in depth, little is known about the impact of cannabis use on mood and suicidality in young adulthood.
A recent meta-analysis published in JAMA Psychiatry (doi:10.1001/jamapsychiatry.2018.4500) shows that cannabis use during adolescence is associated with a higher risk of developing subsequent major depression and suicidal behaviour.
The studies analysed looked at cannabis use in adolescents younger than 18 years and the subsequent development of depression between the ages of 18 to 32 years. 269 studies were included for full-text review, 35 were selected for further review, and 11 studies of 23 317 individuals were included in the quantitative analysis. The odds ratio (OR) of developing depression for cannabis users in young adulthood compared with nonusers was 1.37 (95% CI, 1.16–1.62). The pooled OR for suicidal ideation was 1.50 (95% CI, 1.11–2.03), and for suicidal attempt was 3.46 (95% CI, 1.53–7.84). The pooled OR for anxiety was not statistically significant: 1.18 (95% CI, 0.84–1.67).
The authors conclude that although individual-level risk remains moderate to low, and results from this study need to be confirmed, the high prevalence of adolescents consuming cannabis generates a large number of young people who could develop depression and suicidality. This is an important public health problem and concern that should be properly addressed by health care policy.