Researchers at Bristol University, UK, have carried out an analysis of dozens of trials of the medical benefits of cannabis.
Dr Penny Whiting and her team looked at 79 randomised trials including 6,462 participants. This indicated "moderate-quality evidence" to support the use of cannabinoids (chemical compounds that are the active principles in cannabis) for chronic pain or spasticity due to multiple sclerosis.
The evidence suggesting that cannabinoids were associated with improvements in nausea and vomiting due to chemotherapy, sleep disorders, and Tourette syndrome was "lower-quality", they report. They evidence that cannabinoids could improve anxiety, depression, or psychosis was "very low-quality".
They explain in the Journal of the American Medical Association that most studies suggested cannabinoids were associated with improvements in symptoms, but these associations did not reach statistical significance in all studies.
Despite the introduction of laws to permit the medical use of cannabis in 23 US states, "their efficacy for specific indications is not clear", explain the team.
Short term side effects of cannabinoids included dizziness, dry mouth, nausea, fatigue, somnolence, euphoria, vomiting, disorientation, drowsiness, confusion, loss of balance, and hallucination.
The authors write: "Further large, robust, randomised clinical trials are needed to confirm the effects of cannabinoids, particularly on weight gain in patients with HIV/AIDS, depression, sleep disorders, anxiety disorders, psychosis, glaucoma, and Tourette syndrome are required. Further studies evaluating cannabis itself are also required because there is very little evidence on the effects and side effects of cannabis," the authors write.
Whiting, P. F. et al. Cannabinoids for Medical Use: A Systematic Review and Meta-Analysis. The Journal of the American Medical Association 24 June 2015 doi:10.1001/jama.2015.6358
Leave a Reply