Evidence for Use of Cannabinoids to Treat Mental Disorders Lacking

Evidence inadequate for cannabinoid use to relieve depression, anxiety, ADHD, Tourette, PTSD, psychosis

HealthDay News – There is little evidence to suggest that cannabinoids improve mental disorders, according to a review published online October 28 in The Lancet Psychiatry.

Nicola Black, PhD, from the University of New South Wales in Sydney, and colleagues conducted a systematic review and meta-analysis to examine the effectiveness and safety of medicinal cannabinoids in the treatment of mental disorders. All studies examining any type and formulation of a medicinal cannabinoid in adults for treating depression, anxiety, attention-deficit/hyperactivity disorder (ADHD), Tourette syndrome, posttraumatic stress disorder, or psychosis were considered. Data were included for 83 eligible studies.

The researchers found that for patients with other medical conditions (primarily chronic noncancer pain and multiple sclerosis), pharmaceutical tetrahydrocannabinol (THC; with or without cannabidiol [CBD]) improved anxiety symptoms (standardized mean difference [SMD], −0.25). In a single study, pharmaceutical THC (with or without CBD) worsened negative symptoms of psychosis (SMD, 0.36). Pharmaceutical THC (with or without CBD) did not significantly affect any other primary outcomes for mental disorders examined; across all studies, pharmaceutical THC did increase the number of people with adverse events and withdrawals due to adverse events (odds ratios, 1.99 and 2.78, respectively) compared with placebo.

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“In light of the paucity of evidence and absence of good quality evidence, and the known risk of cannabinoids, the use of cannabinoids as treatments for mental disorders cannot be justified at this time,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

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