Micah Jonah
March 17, 2026
A comprehensive review of 54 clinical trials conducted between 1980 and 2025 has found little evidence that cannabis-based medicines are effective for most mental health or substance-use disorders. The analysis, published in The Lancet, involved 2,477 participants and included studies from the United States, Canada, and Australia, where medical cannabis use is growing.
Key findings:
No significant benefit was observed for anxiety, psychotic disorders, PTSD, opioid-use disorder, or depression (no trials available).
Limited evidence suggests cannabinoids (CBD + THC) may reduce cannabis withdrawal symptoms and tics in Tourette’s syndrome.
Low-quality evidence indicated potential improvements in sleep for insomnia patients and some autistic traits.
Lead author Jack Wilson stressed the need for more high-quality trials, especially for conditions with few alternative treatments.
The study highlights gaps in scientific evidence, even as medical cannabis use continues to expand globally.
