Cannabis-Based Medicines’ Effectiveness Questioned
WASHINGTON — A recent comprehensive review published in a significant medical journal reveals that cannabis-based medications lack substantial evidence of effectiveness in treating most mental health and substance-use disorders.
As the medical use of cannabinoids rises—especially in countries like the United States, Canada, and Australia—many patients claim to use cannabis to address issues such as anxiety, post-traumatic stress disorder, and sleep disturbances.
The analysis, which appeared in The Lancet, examined data from 54 randomized clinical trials conducted from 1980 until May 2025, involving 2,477 participants. These studies focused on cannabinoids as the primary treatment for mental or substance-use disorders.
Overall, the review indicates no significant advantages for several conditions often cited as reasons for medical cannabis use, including anxiety disorders, psychotic disorders, PTSD, and opioid-use disorder.
“Some individuals might find real benefits, which is fantastic. However, when we evaluate the evidence comprehensively, it just doesn’t support routine use of these medications,” expressed lead author Jack Wilson from the University of Sydney’s The Matilda Centre.
Interestingly, the study revealed a lack of randomized controlled trials on cannabinoids for depression, pointing to a significant gap in available evidence.
That said, there was limited evidence suggesting potential advantages for specific conditions.
A mix of cannabidiol (CBD) and THC—the psychoactive component in marijuana—was found to reduce withdrawal symptoms and lower cannabis consumption among those with cannabis-use disorder.
Additionally, cannabinoids appeared to lessen tic severity in individuals with Tourette’s syndrome.
The researchers also observed a decrease in some autistic traits in individuals with autism spectrum disorder and an increase in sleep duration for insomnia patients treated with cannabis medicines. However, Wilson noted that the overall quality of evidence for autism and insomnia was low.
More high-quality trials with larger, more representative samples are necessary to better understand the therapeutic role of cannabinoids, especially as their clinical usage becomes more widespread.
“Clearly, we need to conduct further research on medical cannabis, particularly for conditions with few alternative treatments,” Wilson stated.
