Scientists Debunk Claims of Marijuana as Anxiety, Mental Health Treatment

New research shows medical and recreational marijuana are ineffective and may be dangerous for treating mental health conditions.

Mar. 17, 2026 at 2:48am

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According to two new studies, using medical or recreational marijuana to ease symptoms of mental health conditions like anxiety, depression, and PTSD does not work. The research, which analyzed results from 54 randomized controlled trials, found no evidence that any form of cannabis is effective for treating these leading reasons people use it. Experts warn that marijuana use, especially high-potency products, can be dangerous and increase the risk of psychotic disorders, self-harm, and suicide, particularly for vulnerable populations like adolescents and those with mood disorders.

Why it matters

Despite a lack of proof of efficacy, doctors continue to prescribe medical marijuana to treat mental health conditions, and the cannabis industry has connections to some of these studies, raising conflicts of interest. This research highlights the need for more scrutiny around the use of marijuana for mental health, as its use is growing even as evidence shows it may be ineffective and even dangerous, especially for vulnerable populations.

The details

The studies analyzed oral formulations of medical marijuana, such as capsules, sprays, and oils, which are different from the smoked cannabis typically used in real life. The research found no evidence that marijuana was effective for treating anxiety, depression, PTSD, anorexia nervosa, bipolar disorder, OCD, or psychotic disorders like schizophrenia. Experts say studies on marijuana are often small and difficult to conduct, but the randomized controlled trials in this review are the gold standard of research.

  • The studies were published on March 17, 2026.

The players

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 one of the studies.

Dr. Deepak Cyril D'Souza

The Vikram Sodhi '92 Professor of Psychiatry and director of the Yale Center for the Science of Cannabis and Cannabinoids in New Haven, Connecticut, who was the senior author of a recent JAMA paper that also explored the effectiveness of natural and synthetic forms of CBD and THC on mental health conditions.

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What they’re saying

“We found no evidence any form of cannabis is effective in treating anxiety, depression or post-traumatic stress disorder, which are three of the leading reasons for which cannabis is prescribed.”

— Jack Wilson, Postdoctoral research fellow (Lancet Psychiatry)

“These two papers clearly show there isn't any evidence to recommend the use of cannabis or cannabis derivatives to treat mental health, yet almost every state in the U.S. approves medical marijuana for mental health conditions.”

— Dr. Deepak Cyril D'Souza, Vikram Sodhi '92 Professor of Psychiatry and director of the Yale Center for the Science of Cannabis and Cannabinoids (JAMA)

The takeaway

This research underscores the need for more scrutiny and evidence-based approaches around the use of marijuana, both medical and recreational, for mental health conditions. While many people may use cannabis without issue, the potential dangers, especially for vulnerable populations, highlight the importance of relying on proven treatments like cognitive behavioral therapy and pharmaceutical approaches rather than unproven and potentially harmful marijuana use.