Cannabinoids in Symptomatic Treatment for People with Multiple Sclerosis: a Systematic Review of Randomised Studies

Purpose of Review The use of cannabinoid-based medicines in symptomatic treatment for people with multiple sclerosis (MS) is high. This review aimed to assess benefit and harms of cannabinoids, including synthetic, herbal and plant-derived cannabinoids, for reducing symptoms in adults with MS. Recent Findings Cannabinoids exert effects of potential relevance to MS: their action of neuroinflammation suppression, their immunomodulatory and neuroprotective effects in the central nervous system could benefit people with MS. Nabiximols is approved and available for people with MS and moderate or severe spasticity in many countries, and cannabinoids are also licensed in several countries for the treatment of chronic neuropathic pain. Summary Compared with placebo, cannabinoids likely reduce the severity of spasticity and improve well-being in the short term. Their effect on chronic neurological pain is uncertain. Serious adverse events are not increased; however, withdrawals due to adverse events are slightly greater in the cannabinoid group than in the placebo group. Most of the included trials had major weaknesses. Studies of high quality, with large sample sizes and longer follow-up period, are needed. Moreover, further research is needed in order to assess the short-and long-term adverse effects of these drugs.