Photo: Getty ImagesCannabis-based medicines have shown little evidence of effectiveness for treating most mental health and substance-use disorders, a large review of past studies shows. 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 (post-traumatic stress disorder) and opioid-use disorder. Researchers also found a reduction in some autistic traits in those with autism spectrum disorder, and increased sleep time in patients with insomnia among those treated with cannabis medicines. "We clearly need to do more research on medical cannabis, particularly for those conditions that have limited alternative treatments," Wilson said.

Source: Otago Daily Times March 17, 2026 14:13 UTC