Medical Cannabis Evidence Remains Limited for Certain Conditions, According to New JAMA Review

A newly published review states that evidence supports medical cannabis use in only limited situations (1). The study explains that while 27% of adults in the US and Canada report ever using medical cannabis, and an estimated 10.5% of the US has ever used cannabidiol (CBD), there is a gap between public knowledge and scientific evidence.

“Patients deserve honest conversations about what the science does and doesn't tell us about medical cannabis,” stated first author Michael Hsu, MD, health sciences clinical instructor at the UCLA Health Department of Psychiatry and Biobehavioral Sciences, in a December 2, 2025, press release from UCLA Health (2).

Other researchers also contributed to the study, including those from University of California, San Francisco; New York University Grossman School of Medicine; Washington University School of Medicine, St. Louis, Missouri; and Harvard Medical School.

Study Highlights: Benefits and Risks

The study, “Therapeutic Use of Cannabis and Cannabinoids: A Review,” was published in JAMA in November 2025. The review included more than 2500 studies published between January 2010 through September 2025 (2).

Some conditions showed potential benefits from the use of cannabinoids:

• Cannabinoids have approval from the US Food and Drug Administration (FDA) for HIV/AIDS–related anorexia, chemotherapy-induced nausea and vomiting, and some pediatric seizure disorders.
• One meta-analysis of randomized clinical trials (RCT) indicated a reduction in nausea and vomiting when comparing cannabinoids with (such as dronabinol and nabilone) and placebo or with comparators
• A meta-analysis of RCTs indicated that cannabinoids had a moderate effect on increasing body weight in patients with HIV/AIDS when compared with placebo

However, risks were also associated with certain administrations and potencies of cannabis:

• RCTs did not support the use of cannabis for acute pain and insomnia
• Longitudinal data from adolescents suggested that compared with low-potency cannabis, high-potency cannabis is associated with an increased risk of psychotic symptoms and generalized anxiety disorder
• An increased risk of coronary heart disease, myocardial infarction, and stroke was associated with daily inhaled cannabis use compared with non-daily use
• One meta-analysis stated that 29% of medical cannabis patients met criteria for cannabis use disorder (CUD)
• Inhaled or high-potency cannabis (more than 10% or 10 mg of THC) are not recommended for medical use

Additionally, clinicians were recommended to check with regulations, potential drug interactions, and contraindications, as well as discuss harm reduction strategies with their patients, including avoiding cannabis use with alcohol, use the lowest effective dose, and avoiding driving.

Several limitations to the study were noted in the press release. Notably, the review was not a systemic review, and a formal risk of bias assessment was not conducted. Some of the studies were observational. Additionally, the variations in products, patients, and the design of the clinical trials could limit the applicability of the trials’ recommendations.

“Further research is crucial to better understand the potential benefits and risks of medical cannabis,” Hsu added. “By supporting more rigorous studies, we can provide clearer guidance and improve clinical care for patients.”

Overall Conclusions

The review indicated that while some conditions saw benefits from cannabinoids compared with placebo, several others were inconclusive or inadequate.

“While many people turn to cannabis seeking relief, our review highlights significant gaps between public perception and scientific evidence regarding its effectiveness for most medical conditions,” Hsu explained (2). “Clear guidance from clinicians is essential to support safe, evidence-based decision-making when discussing medical cannabis with their patients.”

References

1. Michael, H.; Shah, A.; Jordan, A.; Gold, MS.; Hill, KP. Therapeutic Use of Cannabis and Cannabinoids: A Review. JAMA. 2025. DOI: 10.1001/jama.2025.19433
2. Houston, W. Evidence lacking for medical cannabis in most conditions. December 2, 2025. https://www.uclahealth.org/news/release/evidence-lacking-medical-cannabis-most-conditions (Accessed 2025-12-08).