Lancet Psychiatry

Cannabinoids fall short for most psychiatric indications, meta-analysis finds

March 18, 2026

In a systematic review and meta-analysis of 54 randomized trials (N = 2,477), cannabinoids showed small benefits in select conditions but little evidence of broad efficacy across mental disorders or substance use disorders. Combined cannabidiol and delta‑9‑tetrahydrocannabinol was associated with modest reductions in cannabis withdrawal symptoms, cannabis use, and tic severity, while cannabinoids were associated with increased sleep time in insomnia and small reductions in autistic traits. No significant effects were observed for anxiety, PTSD, psychotic disorders, or opioid use disorder; cannabinoids were associated with increased cocaine craving. Cannabis use was associated with higher odds of any adverse event versus control (odds ratio, 1.75, 95% confidence interval, 1.25–2.46; number needed to harm = 7), though risks of serious adverse events or study withdrawal were not increased. Overall evidence quality was low, with nearly half of trials at high risk of bias.

Clinical takeaway: Clinicians should avoid routinely recommending cannabinoids for psychiatric or substance use disorders outside of carefully selected cases, discuss limited efficacy and potential harms with patients, and prioritize evidence-based treatments as first-line care.

Source:

Wilson J, et al. (2026, March 16). Lancet Psychiatry. The efficacy and safety of cannabinoids for the treatment of mental disorders and substance use disorders: a systematic review and meta-analysis. https://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(26)00015-5/fulltext