Study: No Longitudinal Association Between Cannabis Use and Depression

Study: No Longitudinal Association Between Cannabis Use and Depression

By Paul Armentano, NORML

TEL AVIV, ISRAEL — Cannabis use is not associated with increased incidences of major depression, according to longitudinal data published online ahead of print in the Journal of Affective Disorders.

An international team of investigators from Israel and Canada assessed the association between cannabis use, major depressive disorder (MDD) and bipolar disorder (BP) in a three-year prospective study.

Authors determined that future incidence of MDD was not higher among cannabis users compared to nonusers. They reported: “Our results show no significant association between cannabis use and the incidence of major depression.

Conversely, MDD was found to be associated with increased incidence of cannabis use. Regarding BPD, though crude associations were found between cannabis use and consequent mania/hypomania as well as baseline BPD and consequent initiation of cannabis use, in both cases these associations were not maintained in adjusted models of analysis.”

Investigators concluded, “Our results do not support a longitudinal association between cannabis use and increased incidence of MDD; rather, they indicate an inverse relationship between the two, which may be attributed to self-medication factors.”

Full text of the study, “The association between cannabis use and mood disorders: A longitudinal study,” appears in the Journal of Affective Disorders.