Neurological disorders

Evidence Supporting Medical Marijuana Use Is Weak

Evidence supporting the use of cannabinoids—the active compounds in marijuana—for chronic pain, nausea, and vomiting, is weak, and edible medical cannabis products containing delta-9-tetrahydrocannabinol (THC) are often mislabeled according to new research.

In a meta-analysis designed to review the benefits and adverse events of cannabinoids, researchers gathered data from 79 clinical trials, including 6462 participants, on the use of cannabinoids for nausea and vomiting due to chemotherapy, appetite stimulation in patients with HIV/AIDS, chronic pain, spasticity, depression, anxiety, sleep disorders, glaucoma, and Tourette syndrome.1
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Overall, while most trials showed that cannabinoids were associated with improvements in symptoms of the various conditions, the results were not statistically significant.

The quality of evidence for the drug’s use in appetite stimulation in HIV/AIDS, nausea and vomiting with chemotherapy, sleep disorders, and Tourette syndrome was low, and the quality of evidence supporting its use in anxiety was very low. Evidence was of moderate quality for cannabinoids use in treating chronic pain and spasticity.

Cannabinoid use was also associated with an increased risk of short-term adverse events like dry mouth, dizziness, fatigue, nausea, vomiting, disorientation, confusion, balance loss, and hallucination.  

In addition, another recent study examined the dose accuracy of labels for edible medical cannabis products containing THC.2

Researchers purchased 75 edible marijuana products from dispensaries in Los Angeles, San Francisco, and Seattle, and, after testing, found that only 17% were accurately labeled, 23% underreported the THC content, and 60% over reported the THC content.

Both studies were published in JAMA.

—Michael Potts

References:

  1. Whiting PF, Wolff RF, Deshpande S, Di Nisio M, et al. Cannabinoids for medical use. JAMA. 2015;313(24):2456-2473
  2. Vandrey R, Raber JC, Raber ME, et al. Cannabinoid dose and label accuracy in edible medical cannabis products. JAMA. 2015;313(24):2491-2493.