The links between cannabis and depression as well as suicide have been noted in both cross-sectional and longitudinal studies (22; 73; 74) – for instance, a recent meta-analysis notes an odds-ratio of 1.62 for the likelihood of depression in heavy cannabis users (73). Another meta-analysis of four Australasian datasets found that, even upon adjustment for confounders, weekly cannabis use was modestly associated with depression, particularly during adolescence (75). Similarly, for suicide, van Ours et al (76) found that frequent cannabis use (several times per week) was associated with suicidal ideation, particularly in males. In contrast, Price and colleagues, using a cohort of 50,087 Swedish male conscripts reported no association between repeated cannabis use (> 50 times) and completed suicide (odds-ratio 1.04) after adjustment for confounders (77).
