Medical Cannabis: A Review of Evidence and Potential Risks
A comprehensive review led by UCLA Health has revealed a significant gap between public perception and scientific evidence regarding the effectiveness of medical cannabis. The study, published in JAMA, analyzed over 2,500 articles from 2010 to 2025, including randomized clinical trials, meta-analyses, and clinical guidelines.
Despite its growing popularity, medical cannabis lacks adequate scientific backing for most conditions it's commonly used to treat. Chronic pain, anxiety, and insomnia are among the conditions with limited evidence supporting its use. While many people turn to cannabis for relief, the review highlights a disconnect between public belief and scientific understanding.
The review also confirmed that pharmaceutical-grade cannabinoids approved by the U.S. Food and Drug Administration have shown effectiveness in specific conditions, such as HIV/AIDS-related appetite loss, chemotherapy-induced nausea and vomiting, and certain severe pediatric seizure disorders. However, for most other conditions, the evidence remains inconclusive or lacking.
Potential Health Risks
The study also shed light on potential health risks associated with cannabis use. High-potency cannabis may be linked to increased rates of psychotic symptoms and generalized anxiety disorder in adolescents. Additionally, about 29% of medical cannabis users met the criteria for cannabis use disorder, and daily use, especially of inhaled and high-potency products, may pose cardiovascular risks, including higher rates of coronary heart disease, heart attack, and stroke.
The review emphasizes the importance of careful patient screening by clinicians for cardiovascular disease and psychotic disorders, as well as evaluating potential drug interactions and benefits-risks before considering THC-containing products for medical purposes.
Limitations and Future Research
The authors noted several limitations of the review, including the absence of a systematic review and formal risk of bias assessment. They also highlighted the potential for confounding in observational studies and the need for further research to better understand the benefits and risks of medical cannabis.
Dr. Michael Hsu, the first author of the review, emphasized the importance of honest conversations between patients and healthcare providers about the limitations of current scientific knowledge on medical cannabis. He stated, 'Further research is crucial to providing clearer guidance and improving clinical care for patients.'
