“The National Academies of Sciences, Engineering and Medicine conducted a rapid turn-around comprehensive review of recent medical literature on The Health Effects of Cannabis and Cannabinoids.

In the Therapeutics chapter reviewed here, the report concluded that there was conclusive or substantial evidence that Cannabis or cannabinoids are effective for the treatment of pain in adults; chemotherapy-induced nausea and vomiting and spasticity associated with multiple sclerosis. Moderate evidence was found for secondary sleep disturbances. The evidence supporting improvement in appetite, Tourette syndrome, anxiety, posttraumatic stress disorder, cancer, irritable bowel syndrome, epilepsy and a variety of neurodegenerative disorders was described as limited, insufficient or absent. A chapter of the NASEM report enumerated multiple barriers to conducting research on Cannabis in the US that may explain the paucity of positive therapeutic benefits in the published literature to date.

The 2017 National Academies of Sciences, Engineering and Medicine report, like the 1999 Institute of Medicine publication before it, did conclude that there is evidence to support the therapeutic effect of Cannabis and cannabinoids in a number of conditions. Although it is well appreciated that the plural of anecdote is not evidence, it must also be remembered that in the case of evaluating the therapeutic effects of Cannabis as published in the medical literature, the absence of evidence is not necessarily indicative of evidence of the absence of effectiveness. ”

http://www.ejinme.com/article/S0953-6205(18)30003-7/fulltext