Is Cannabis Medicine?
Purchasers seem to think so but new research says not so fast.
Updated March 17, 2026 | Reviewed by Tyler Woods
Many patients turn to cannabis or cannabidiol (CBD) for chronic pain , appetite loss, sleep disorders, and other conditions, believing “natural” equals “safe and effective.” However, a recent comprehensive JAMA review challenges this assumption. Lead author, Harvard University’s Kevin P. Hill, M.D., writes, “Beyond FDA-approved indications, the evidence for cannabis and cannabinoids as medical treatment is limited.” After evaluating more than a thousand studies, cannabis and cannabinoids remain unproven for most medical uses.
Cannabis is a plant containing hundreds of biologically active compounds (THC, CBD, minor cannabinoids, flavonoids, etc.), such as the psychoactive compound THC (delta-9-tetrahydrocannabinol), as well as non-intoxicating ingredients. THC is responsible for the "high" associated with marijuana use.
Because many cannabis users use the drug chronically, and some effects (cardiovascular, psychiatric , dependence) take years before emerging, long-term data have been needed—but until recently, remained absent. For example, the JAMA review highlighted elevated cardiovascular risks with daily inhaled cannabis use, and also that nearly one-third of users develop addictions to cannabis.
Other controversial medications (like ketamine , psilocybin) are rigorously studied under more conventional regulatory frameworks, allowing proof of safety and efficacy with well-designed, placebo -controlled FDA trials, including standardized dosing.
Medical Cannabis: Comparable to Medicinal Alcohol?
Medicinal alcohol was used during the early 20th century before antibiotics and most modern medicines, especially during Prohibition (1920-1933), when doctors prescribed alcohol for anemia, hypertension, heart disease, tuberculosis, typhoid, and pneumonia infections. It was also used as a painkiller during surgery.
Back then, doctors prescribed alcohol for patients to obtain from pharmacists. Prescriptions would often be a pint of whiskey. So, I wondered to myself, is “medical cannabis” today used for illnesses not easily treated now , as alcohol was during Prohibition times?
We have antibiotics and many treatments, but we can’t cure everything, and many adults use medical marijuana for chronic pain. Child and adolescent psychiatrist Sarah Y. Vinson, MD. Chair of the psychiatry department at the Morehouse School of Medicine in Atlanta, says some young people use marijuana because it’s the only “medicine” they can access. For some teens, marijuana is to emotional pain as acetaminophen is to physical pain. A significant reason for this lies in the difficulty of obtaining adequate (or any) mental health care and/or medications for adolescents and young adults.
Back to the JAMA Study
The JAMA researchers performed an in-depth review of more than 1,000 studies. The bottom line? Researchers concluded there was “insufficient evidence for most medical purposes. The central conclusion is stark: for the majority of medical conditions for which cannabis or cannabinoids are used—including some of the most common ones (pain, anxiety , insomnia )—the current evidence is inadequate to support their use.”
The lack of robust data favoring cannabis as a treatment for anxiety, insomnia, depression , eating disorders, chronic pain, and other conditions is troubling because cannabis is often taken by people with these problems, hoping for relief. However, despite frequent off-label use, the review found no good, or even mild, reviews showing benefit.
Lack of cannabis quality control and dosing issues are essential to consider as well. Unlike conventional pharmaceuticals, most cannabis products on the market are not standardized: potency, formulation, and dosing vary considerably.
Hill told me, “Cannabis, like alcohol, lacks evidence as a true FDA-approved medicine, and both have the potential for harm. In most cases, cannabis risks outweigh the yet-to-be-proven benefits. Cannabis is not a first-line therapy . We consider cannabis or cannabinoids (where legal) only after first-line, evidence-based treatments have failed."
Cannabis also has adverse effects. The JAMA review highlighted that daily inhaled use is associated with increased risks of coronary heart disease, heart attack, and stroke. Also, nearly one-third of adult medical cannabis users develop a cannabis use disorder. (Although most people who use cannabis are not addicted, addiction is possible.)
So, does this mean we should shut down all those cannabis dispensaries? Putting the genie back in the bottle may not be so easy.
Dr. Kevin Hill and colleagues in JAMA emphasized that cannabis research to date suffers from widely variable cannabinoid content, terpenes, and contaminants—low-quality evidence, small studies, inconsistent endpoints, and unblinded research designs. Anecdotal studies from one preparation cannot be generalized. But a new clinical research trial published in Nature suggests that cannabis researchers may be evolving.
Dr. Matthias Karst, Professor of Pain Medicine at Germany's Hannover Medical School, just conducted a research trial specifically addressing these issues using pharmaceutical-grade , chemically consistent cannabis extract (VER-01) for chronic low back pain. They employed an FDA-appropriate phase-3, placebo-controlled, double-blind methodology with a large sample size. They also measured critical outcomes (pain scores, function, sleep, etc.), enabling them to show efficacy, safety, and durability. This research is rigorous and reproducible, exactly the standardized clinical research Kevin Hill and colleagues have called for in the American Journal of Psychiatry (2022) and, more recently, in JAMA , which they argue is essential before cannabis-based therapies can be responsibly integrated into evidence-based medicine.
Cannabis is no medical miracle. Given that decades have passed to prove its safety and efficacy, and that no compelling or sufficient data have been produced, we should not oversell its benefits. For example, there are no psychiatric indications approved by the FDA for cannabinoids, and limited evidence supporting the therapeutic use of cannabinoids for psychiatric disorders. The current evidence is insufficient to support prescribing cannabinoids for the treatment of psychiatric disorders. To date, evidence supporting cannabinoid prescription beyond FDA indications is strongest for the management of chronic pain and spasticity.
There is clear evidence that cannabinoids have potential for harm, especially in vulnerable populations such as adolescents and those at risk of psychotic disorders.
Dr. Hill of Harvard told me, “Cannabis has been promoted for its ‘medicinal benefits’ like alcohol was during Prohibition. But as with alcohol, there is a lack of quality evidence supporting cannabis, and both alcohol and cannabis have potential for harm. In most cases, cannabis risks outweigh the yet-to-be-proven benefits. Consider cannabis or cannabinoids (where legal) only after first-line, evidence-based treatments have failed—ideally, after careful discussion of risks vs. uncertain benefits.”
Facebook image: LTim/Shutterstock
Hill KP, Gold MS, Nemeroff CB, McDonald W, Grzenda A, Widge AS, Rodriguez C, Kraguljac NV, Krystal JH, Carpenter LL. Risks and Benefits of Cannabis and Cannabinoids in Psychiatry. Am J Psychiatry. 2022 Feb;179(2):98-109. doi: 10.1176/appi.ajp.2021.21030320. Epub 2021 Dec 8. PMID: 34875873.
Hsu M, Shah A, Jordan A, Gold MS, Hill KP. Therapeutic Use of Cannabis and Cannabinoids: A Review. JAMA. 2025 Nov 26. doi: 10.1001/jama.2025.19433. Epub ahead of print. PMID: 41296368.
Kansagara D, Terry GE, Ayers CK, D'Souza DC. Cannabis and Mental Health: A Review. JAMA Intern Med. 2026 Mar 9. doi: 10.1001/jamainternmed.2025.8215. Epub ahead of print. PMID: 41801216.
Sarkar PR, Gold MS, Hill KP. Editorial: Cannabis and cannabinoids in psychiatry. Front Public Health. 2025 May 13;13:1618252. doi: 10.3389/fpubh.2025.1618252. PMID: 40433483; PMCID: PMC12106038.
Karst M, Meissner W, Sator S, Keßler J, Schoder V, Häuser W. Full-spectrum extract from Cannabis sativa DKJ127 for chronic low back pain: a phase 3 randomized placebo-controlled trial. Nat Med. 2025 Sep 29. doi: 10.1038/s41591-025-03977-0. Epub ahead of print. PMID: 41023483.
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Mark S. Gold, M.D., is a pioneering researcher, professor, and chairman of psychiatry at Yale, the University of Florida, and Washington University in St Louis.
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