"A total of 11 articles met the inclusion criteria for the metaanalysis (Figure 1): 7 for depression10,16,34,38,44-46; 3 for anxiety,16,38,44 3 for suicidal ideation,41,47,57 and 3 for suicide attempts.10,54,57 To estimate the extent to which cannabis use
during adolescence was associated with increased odds of developing depression in young adulthood, we pooled results from 7 studies.10,16,34,38,44-46 The pooled OR [Odds Ratio] for depression during young adulthood among cannabis users compared with nonusers was 1.37 (95% CI, 1.16-1.62; I2 = 0%; Figure 2). Cannabis use during adolescence was associated with increased odds of developing anxiety in young adulthood when pooling 3 studies16,38,44 (OR, 1.18; 95% CI, 0.84-1.67; I2 = 42.0%; Figure 2). Suicidal ideation is a symptom of depression, while suicide represents one of the most severe sequelae of mental illness. Results from 3 studies that had measured the association of cannabis use during adolescence with subsequent suicidal ideation within adolescence41,57 and in young adulthood47 were pooled with a resultant OR of 1.50 (95% CI, 1.11-2.03; I2: 0%; Figure 3). For the number of suicide attempt outcomes within adolescence54,57 or during young adulthood,10 the results were pooled with a resultant OR of 3.46 (95% CI, 1.53-7.84; I2 = 61.3%; Figure 3)."
Gobbi G, Atkin T, Zytynski T, et al. Association of Cannabis Use in Adolescence and Risk of Depression, Anxiety, and Suicidality in Young Adulthood: A Systematic Review and Meta-analysis. JAMA Psychiatry. 2019;76(4):426–434. doi:10.1001/jamapsychiatry.2018.4500.