A Review of the relationship between cannabis use and affective disorders.

This paper examines the relationship between cannabis use and the affective disorders of depression, bipolar disorder, and mania. The literature is reviewed, examining both sides of the debate. The literature suggests that cannabis is most strongly related to depression in heavy use, in particular in adolescents. Cannabis may be used to self-medicate depressive symptoms, though there is little evidence that this is effective. Whilst cannabis may also be used for self-medication in bipolar disorder, it has a number of effects on the emergence, presentation, treatment, and prognosis of the illness. Cannabis use may also increase sub-clinical manic symptoms in non-clinical populations. Future research is then suggested to resolve some of the discrepancies in the literature.