A new study in The Lancet says that medical marijuana does not work well for anxiety, depression, or PTSD. It is the biggest review so far that looks at how safe and useful cannabinoids are for many mental‑health problems.
Many people in the U.S. and Canada already use cannabis for health reasons. About 27 % of adults aged 16‑65 say they take it, and half of them say they use it to feel better mentally.
One expert warned that regular use of medicinal cannabis might actually make mental health worse. It could raise the chance of psychotic symptoms, lead to cannabis‑use disorder, and delay better treatments.
Only Small Hints for Some Other IssuesThe researchers saw a few possible good effects. These include helping people who are already dependent on cannabis, children with autism, people who have trouble sleeping, and those with tics or Tourette’s syndrome.
However, the evidence for these uses is weak. The quality of the studies is low, so doctors should be cautious before recommending cannabis for these conditions.
There is stronger proof that cannabis can lower seizures in certain types of epilepsy, reduce muscle stiffness in multiple sclerosis, and ease some kinds of pain. But for mental‑health disorders, the data fall short.
Mixed Outcomes for Substance‑Use ProblemsThe review also examined cannabis as a treatment for other drug addictions. Results were different depending on the substance.
For people addicted to cannabis, an oral form of the plant, when combined with therapy, helped some quit smoking.
In contrast, for individuals with cocaine dependence, cannabis actually increased cravings, suggesting it could make the problem worse.
Calls for Tighter RulesBecause medical cannabis use is growing fast, major health groups like the American Medical Association are worried about the lack of regulation and uncertain safety.
The study aims to give doctors clear, evidence‑based information so they can choose treatments that work and avoid those that might cause harm.
Huge Global Review Over 45 YearsThe conclusions come from a systematic review and meta‑analysis of 54 randomized controlled trials done worldwide between 1980 and 2025.