Background and objectives: Cannabis use is common in people with and mood and anxiety disorders (ADs), and rates of problematic use are higher than in the general population. Given recent policy changes in favor of cannabis legalization, it is important to understand how cannabis and cannabinoids may impact people with these disorders. We aimed to assess the effects of cannabis on the onset and course of depression, bipolar disorder, ADs, and post-traumatic stress disorder (PTSD), and also to explore the therapeutic potential of cannabis and cannabinoids for these disorders.
Methods: A systematic review of the literature was completed. The PubMed® database from January 1990 to May 2018 was searched. We included longitudinal cohort studies, and also all studies using cannabis or a cannabinoid as an active intervention, regardless of the study design.
Results: Forty-seven studies were included: 32 reported on illness onset, nine on illness course, and six on cannabinoid therapeutics. Cohort studies varied significantly in design and quality. The literature suggests that cannabis use is linked to the onset and poorer clinical course in bipolar disorder and PTSD, but this finding is not as clear in depression and anxiety disorders (ADs). There have been few high-quality studies of cannabinoid pharmaceuticals in clinical settings.
Conclusions and scientific significance: These conclusions are limited by a lack of well-controlled longitudinal studies. We suggest that future research be directed toward high-quality, prospective studies of cannabis in clinical populations with mood and ADs, in addition to controlled studies of cannabinoid constituents and pharmaceuticals in these populations. (Am J Addict 2019;00:00-00).
© 2019 American Academy of Addiction Psychiatry.