A comprehensive new review of medical cannabis research has delivered a surprising conclusion: for many conditions where it is commonly promoted, there is insufficient scientific evidence to support its effectiveness. The study, published in the prestigious Journal of the American Medical Association (JAMA), analyzed 124 studies selected from over 2,500 papers published between 2010 and late 2025.
Researchers from the University of California, Los Angeles (UCLA) reaffirmed that medicinal cannabis appears effective for specific, FDA-approved uses. These include reducing chemotherapy-induced nausea and vomiting, stimulating appetite in HIV patients, and treating certain severe childhood seizure disorders. However, the authors argue these are exceptions. "Evidence from randomized clinical trials does not support the use of cannabis or cannabinoids for most conditions for which it is promoted, such as acute pain and insomnia," the authors write.
The review also highlighted potential health risks associated with frequent or high-potency use, including increased risks of psychotic symptoms, generalized anxiety disorder, and cardiovascular disease. "While many people turn to cannabis seeking relief, our review highlights significant gaps between public perception and scientific evidence," says first author Michael Hsu, a clinical researcher at UCLA.
However, the study has faced criticism. Simon Erridge, Director of Research at Curaleaf Clinic in the UK, questioned the methodology. "There appears to be a tendency in the JAMA review to emphasize negative outcomes whilst giving less prominence to research suggesting therapeutic benefits," Erridge told Cannabis Health. The authors themselves acknowledged limitations, noting that "some relevant articles may have been missed" and that a formal risk of bias assessment wasn't conducted for individual studies.
This follows a 2023 review which reached similar conclusions but found some evidence for chronic pain relief. Hsu emphasizes that "further research is crucial" to provide clearer guidance for patients and clinicians.
