A new paper claims medical cannabis lacks adequate scientific backing for most of the conditions it is commonly used to treat, including chronic pain, anxiety and insomnia.
For the study, published in JAMA, researchers at UCLA health reviewed more than 2,500 articles published from January 2010 through September 2025, including randomized clinical trials, meta-analyses and clinical guidelines. More than 120 studies were prioritized based on their large samples, recency, topics covered and relevancy.
According to the review, pharmaceutical-grade cannabinoids approved by the U.S. Food and Drug Administration have demonstrated effectiveness only in a narrow range of conditions. These include medications for HIV/AIDS-related appetite loss, chemotherapy-induced nausea and vomiting and certain severe pediatric seizure disorders, such as Dravet syndrome and Lennox-Gastaut syndrome.
For most other conditions, the evidence remains either inconclusive or lacking, the review found. While more than half of people who use medical cannabis report using it for chronic pain, current clinical guidelines recommend against cannabis-based medicines as first-line treatment for chronic pain.
The review also highlighted potential health risks associated with cannabis use. Longitudinal data from adolescents indicated that high-potency cannabis may be linked to increased rates of psychotic symptoms (12.4% versus 7.1% for low-potency) and generalized anxiety disorder (19.1% versus 11.6%).
The review emphasizes that clinicians should carefully screen patients for cardiovascular disease and psychotic disorders, evaluate potential drug interactions and assess whether the risks outweigh the benefits before considering THC-containing products for medical purposes.
“Patients deserve honest conversations about what the science does and doesn't tell us about medical cannabis,” said the review’s first author Michael Hsu of UCLA Health. “Further research is crucial to better understand the potential benefits and risks of medical cannabis. By supporting more rigorous studies, we can provide clearer guidance and improve clinical care for patients.”
Data from UCLA Health