“Cannabis does have therapeutic properties for certain indications.”   https://www.ncbi.nlm.nih.gov/pubmed/29302228

“The legislative policies that have been established to reduce the risks in relation to cannabis have long represented an obstacle to research concerning medical cannabis use. Improved knowledge of the endocannabinoid system and of exocannabinoids has proven that cannabis may have significant therapeutic effects.”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741114/