Cannabis Associated With Poorer Symptom Course in Anxiety, Mood Disorders

Recent cannabis use was associated with poorer symptomatic course and treatment outcome in patients with anxiety and mood disorders, according to results from a systematic literature review published in the Journal of Clinical Psychiatry.

Twelve studies with a combined cohort of 11,959 individuals met inclusion criteria for systematic review. Each publication had a longitudinal cohort-based study design with participants meeting baseline criteria for a mood or anxiety disorder. Each study also had an independent variable focusing on cannabis use, as well as an analysis of the symptomatic course and/or treatment outcome of anxiety or mood disorders. The studies captured posttraumatic stress disorder (n=4), panic disorder (n=1), bipolar disorder (n=5), and depressive disorder (n=2). “Recent” cannabis use was described as any use or greater frequency of use during the past 6 months.

Across 11 studies, recent cannabis use was associated with poorer symptom course in patients with any psychiatric disorder. Compared with abstinence, “any” baseline cannabis use (P <.0001) or sustained use over time (P <.01) was associated with greater posttraumatic stress symptom severity in the 4 months following baseline assessments. Cannabis use was also associated with greater symptom severity for bipolar disorder, with 1 analysis finding that continued cannabis use over 1 year was associated with higher recurrence of mania (P =.048) and shorter time to recurrence (P =.034). Cannabis use disorder was associated with an elevated number of depressive symptoms (P =.0019), specifically the manifestation of anhedonia (P =.0048) and insomnia/hypersomnia (P =.005), between baseline and follow-up, compared with no use. The majority (83.3%) of analyzed studies also suggested that cannabis was associated with poorer treatment outcomes, specifically for those with posttraumatic stress, depressive disorder, and bipolar disorder.  

Researchers emphasized that these observations about cannabis are speculative in nature and that the observational study design and heterogeneity across outcome assessments limit the certainty of these results. Still, such data may be useful to clinicians in gaining insight on the potential risks of cannabis use among their patients with anxiety or mood disorders. 

Reference

Mammen G, Rueda S, Roerecke M, Bonato S, Lev-Ran S, Rehm J. Association of cannabis with long-term clinical symptoms in anxiety and mood disorders: a systematic review of prospective studies. J Clin Psychiatry. 2018;79(4):17r11839.