March 16 (Reuters) – Cannabis-based medicines have shown little evidence of effectiveness for treating most mental health and substance-use disorders, according to a large review of past studies published in a major medical journal on Monday.
Medical use of cannabinoids has been expanding, including in the United States, Canada and Australia, where many patients report using cannabis products to manage conditions such as anxiety, post-traumatic stress disorder and sleep problems.
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Researchers reviewed data from 54 randomized clinical trials conducted between 1980 and May 2025 involving 2,477 participants for their analysis published in The Lancet. The studies assessed cannabinoids as a primary treatment for mental disorders or substance-use disorders.
Overall, the review found no significant benefit for several conditions commonly cited as reasons for medical cannabis use, including anxiety disorders, psychotic disorders, PTSD and opioid-use disorder.
Cannabis shows little benefit for most mental disorders, data review finds
