An analysis has found moderate-quality evidence supporting the use of cannabinoids for certain types of pain, but not for other conditions such as nausea and sleep disorders. This review of nearly 80 randomized controlled trials has been published in JAMA.
Penny F. Whiting, PhD, of the University of Bristol, Bristol, United Kingdom, and colleagues collected data from 79 randomized controlled clinical trials with 6,462 patients on the use of cannabinoids for nausea and vomiting due to chemotherapy, appetite stimulation in HIV/AIDS, chronic pain, spasticity due to multiple sclerosis or paraplegia, depression, anxiety disorder, sleep disorder, psychosis, glaucoma, or Tourette syndrome. Study quality was determined using the Cochrane risk of bias tool.
Improvements in symptoms with use of cannabinoids were not statistically significant in most studies. Only two trials evaluated cannabis and there was no evidence of differential effects between cannabis and other cannabinoids. There was moderate-quality evidence suggesting that cannabinoids could be beneficial for the treatment of chronic neuropathic or cancer pain, along with spasticity due to multiple sclerosis but low-quality evidence for nausea and vomiting due to chemotherapy, weight gain in HIV, sleep disorders, and Tourette’s syndrome. For cannabinoids in the treatment of anxiety, there was very low-quality evidence; in addition, there was low-quality evidence for no effect on psychosis and very low-level evidence for no effect on depression. No clear evidence for benefits or risks with specific types of cannabinoids or modes of administration was noted. An increased risk of short-term adverse events including dizziness, dry mouth, nausea, fatigue, somnolence, euphoria, vomiting, disorientation, drowsiness, confusion, loss of balance, and hallucination was also found.
In an accompanying editorial, Deepak Cyril D’Souza, MBBS, MD, and Mohini Ranganathan, MD, of the Yale University School of Medicine noted that large double-blind randomized clinical trials are needed to test the short- and long-term safety and efficacy of medical marijuana for various medical conditions. They also added that “since medical marijuana is not a life-saving intervention, it may be prudent to wait before widely adopting its use until high-quality evidence is available to guide the development of a rational approval process.” Currently 23 states and the District of Columbia have introduced laws permitting the use of medical marijuana.
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