Marijuana doesn't help mental health conditions according to major review

A major new study has claimed that there is 'very little evidence' that cannabis helps most mental health disorders.

Despite a worldwide surge in people using it for these purposes, the recently published research outlines that there is 'very little evidence for its efficacy' in treating most mental health and substance disorders, including anxiety, anorexia nervosa, psychotic disorders, post-traumatic stress disorder, or opioid use disorder.

As mentioned, it comes at a time when medical cannabis and cannabinoid use is growing in America, Canada, and Australia, as more people are turning to the drug to help with things like anxiety, sleep disorders, and post-traumatic stress disorder.

The review, which was published in The Lancet on Monday (16 March), reviewed data from 54 randomized clinical trials conducted between ⁠1980 and May 2025 involving 2,477 participants.

It assessed the use of cannabinoids as a primary treatment for mental health disorders or substance-use disorders, but as we say, it found that, surprisingly, there was no significant benefit for several conditions.

A new review of the medicinal use of cannabis has been published (Getty Stock Image)

Researchers penned: "There were no significant effects on outcomes associated with anxiety, anorexia nervosa, psychotic disorders, post-traumatic stress disorder, and opioid use disorders."

They concluded that 'given the scarcity of evidence, the routine use of cannabinoids for the treatment of mental disorders and substance use disorders is currently rarely justified'.

While Jack Wilson, a postdoctoral research fellow at the University of Sydney’s Matilda Centre for Research in Mental Health and Substance Use, and the lead author of the study, told CNN: "The cannabis medications being administered in these studies were largely oral formulations, such as capsules, sprays, or oils.

"In real life, people typically use smoked cannabis, and there is even less evidence of its effectiveness for mental health."

He also told Reuters that 'some people may experience legitimate benefits, and that's great,' but when looking at the evidence as a whole, we just 'don't see that the evidence is quite there ​for the routine use of these medicines'.

However, the study did find that there were some 'promising findings' for cannabinoids as a treatment for cannabis use disorder, autism spectrum disorder, insomnia, and tic or Tourette's syndrome.

There were no significant effects on anxiety, anorexia nervosa, psychotic disorders, post-traumatic stress disorder, and opioid use disorders (Getty Stock Image)

The researchers added that more high-quality trials with larger and ⁠more representative ​samples are needed in the future to clarify the therapeutic role of ​cannabinoids, specifically as their clinical use grows.

"We clearly need to do more research on medical cannabis, particularly for those conditions ​that have limited alternative treatments," Wilson confirmed.

As reported by The Guardian, though, a trade body has hit out at the study and argued that cannabis does relieve the symptoms of anxiety and post-traumatic stress.

Mike Morgan-Giles, the chief executive of the Cannabis Industry Council, argued: "Real-world evidence, including findings from T21, consistently shows that medical cannabis reduces symptoms for patients with anxiety and post-traumatic stress.

"Regrettably, this latest paper adds more heat than light and does not adequately reflect how clinical prescribing is undertaken in the UK."