Major cannabis study finds little proof for popular medical claims, flags big dangers

OG article by Khloe Quill

December 19, 2025

A comprehensive review published in JAMA analyzed over 2,500 scientific papers from the past 15 years on medical cannabis, revealing limited evidence supporting its effectiveness for most conditions. Led by UCLA researchers with contributions from Harvard, UC San Francisco, Washington University, and New York University, the study highlights significant gaps between public perception and scientific proof. Dr. Michael Hsu, the lead author, emphasized that while many seek relief through cannabis, the evidence is insufficient for widespread medical claims. Strong support exists only for FDA-approved cannabinoid treatments for HIV/AIDS-related appetite loss, chemotherapy-induced nausea, vomiting, and severe pediatric seizures. For common issues like chronic pain, insomnia, anxiety, and PTSD, randomized trials showed no meaningful benefits. Safety concerns are prominent: high-potency cannabis in youth links to higher psychotic symptoms and anxiety, while daily inhaled use increases risks of coronary heart disease, heart attack, and stroke. Clinicians are urged to screen for cardiovascular risks, mental health history, and drug interactions. The review, a narrative rather than systematic one, notes limitations like reliance on observational data. Patients deserve honest discussions about cannabis's proven versus assumed benefits, weighing risks carefully.