How effective are cannabinoids for a broad range of medical conditions?
The best evidence supports the use of dronabinol and nabiximols for chronic pain, nabiximols for spasticity, cannabidiol for epilepsy, dronabinol for Tourette syndrome and Parkinson disease, and nabiximols for sleep, substance use disorder, and depression.
Meta-analysis (randomized controlled trials)
A recent POEM concluded that there is some evidence that cannabinoids are beneficial for chronic pain. This broader systematic review evaluated the effectiveness of medical cannabinoids for a range of disorders. The authors searched 8 databases for randomized trials of medical cannabinoids, including dronabinol, nabilone, cannabidiol, and nabiximols (nabiximols are combination THC/CBD mucosal sprays that are not approved in the United States yet). The authors identified 152 randomized trials with a total of 12,123 participants for conditions such as chronic pain, spasticity, nausea and vomiting, poor appetite, Huntington chorea, and epilepsy. The quality of evidence was moderate or high for nabiximols (for chronic pain, spasticity, sleep, substance use disorder, and depression), cannabidiol (epilepsy), and dronabinol (Tourette syndrome and Parkinson disease). For most of these comparisons, small to moderate benefits in outcomes were observed, with standardized mean differences largely between 0.2 and 0.5 lower for the intervention than the placebo. A large benefit was seen for dronabinol for Tourette syndrome, with a standardized mean difference that was 1.01 lower. Adverse events were more common with all cannabinoids, in a range of 147 to 251 more events per 1000 persons treated. However, retention in trials, a measure of overall tolerability, was similar between the cannabinoid groups and the placebo groups.
Mark H. Ebell, MD, MS
University of Georgia