If you’re among the millions of Americans reaching for cannabis to ease anxiety, depression or post-traumatic stress disorder (PTSD), a recent study suggests you might want to reconsider.
The largest review to date examined both the safety and effectiveness of medicinal cannabis across mental health conditions. Its conclusion is that there’s no evidence it works for these common uses. Published in The Lancet — one of the world’s most prestigious medical journals — the analysis drew from 54 randomized controlled trials conducted worldwide over 45 years.
Around 27% of people aged 16 to 65 in the U.S. and Canada report using cannabis medically. Roughly half of those folks say they’re using cannabis to manage mental health symptoms.
Dr. Jack Wilson from the University of Sydney’s Matilda Centre in Australia led the research team. He says the following in a summary of the findings:
“Though our paper didn’t specifically look at this, the routine use of medicinal cannabis could be doing more harm than good by worsening mental health outcomes, for example a greater risk of psychotic symptoms and developing cannabis use disorder, and delaying the use of more effective treatments.”
The study found some limited evidence that cannabis might help with a handful of other conditions, including cannabis dependency itself, autism, insomnia and tics or Tourette’s syndrome. But Wilson cautioned that even this evidence is weak:
“The overall quality of evidence for these other conditions, such as autism and insomnia, was low. In the absence of robust medical or counseling support, the use of medicinal cannabis in these cases [is] rarely justified.”
Where cannabis shows more promise
The news isn’t all negative. Researchers pointed to evidence that medicinal cannabis may help reduce seizures in certain forms of epilepsy, ease muscles stiffness or spasms in people with multiple sclerosis and manage specific types of pain.
And the findings on substance-use disorders have more nuance. Cannabis-based treatments showed some potential for helping people with cannabis dependency, similar to how methadone treats opioid addiction.
But when used to treat cocaine-use disorder, it actually increased cravings and could worsen that particular addiction.
The American Medical Association and other major medical organizations have raised concerns about limited regulation and uncertainty surrounding cannabis products. This study could add momentum to calls for stricter oversight.
