Medical cannabis has been embraced as a natural remedy for everything from chronic pain to anxiety and sleepless nights. Dispensaries are busy, public support is high, and many patients assume that science has already caught up with the enthusiasm.

But a sweeping new review of the evidence to date tells a far more cautious story.

Researchers from the University of California, Los Angeles and San Francisco examined more than 2,500 scientific papers on cannabis and cannabinoid use released between January 2010 and September 2025. The review included randomized clinical trials, meta-analysis and clinical guidelines, with more than 120 studies prioritized for their size, relevance and methodological strength. The conclusion? While interest in medical cannabis continues to surge, strong scientific support exists for only a narrow set of uses.

Consider whether possible harms outweigh benefits before recommending THC-containing products.

“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,” lead author Dr. Michael Hsu, a health sciences clinical assistant professor in the UCLA Health Department of Psychiatry and Behavioral Sciences, said in statement accompanying the study.

Public belief has clearly raced ahead of the data. For instance, a 2018 survey cited in the review found that 27 percent of adults in the United States and Canada had used cannabis or related compounds such as CBD to address health concerns like pain, anxiety or sleep issues. Yet, when researchers examined the quality of the evidence behind these popular uses, support was often weak or inconclusive.

The review found that only a handful of pharmaceutical-grade cannabinoid products approved by the U.S. Food and Drug Administration have demonstrated clear clinical benefits. These include treatments for chemotherapy-induced nausea and vomiting, HIV/AIDS-related appetite loss and severe pediatric seizure disorders. Aside from these indications, the evidence becomes far murkier.

Chronic pain is a prime example. Although more than half of medical cannabis users report trying it for pain relief, current clinical guidelines do not recommend cannabis-based treatments as a first-line option.

Kevin P. Hill, an addiction psychiatrist at Beth Israel Deaconess Medical Center in Boston and a co-author of the study. acknowledged that there are legitimate reasons to use cannabis for issues like pain, but that many people who say they're using it medically, are just rationalizing their recreational use.

That distinction matters, especially when potential risks are considered. The UCLA-led analysis found that about 29 percent of medical cannabis users meet criteria for cannabis use disorder, a condition marked by problematic patterns of use. The risk appears higher with daily consumption and with THC-containing products.

The review also flagged mental health concerns, particularly for adolescents. Long-term studies show that teens using high-potency cannabis experience higher rates of psychotic symptoms compared with those using low-potency products (12.4 percent versus 7.1 percent). They also have higher rates of generalized anxiety disorder (19.1 percent versus 11.6 percent).

Cardiovascular risks emerged as another concern. Daily use, especially of inhaled or high-potency cannabis, may increase the risk of heart disease, heart attack and stroke.

While interest in medical cannabis continues to surge, strong scientific support exists for only a narrow set of uses.

Given these findings, the authors urge clinicians to proceed carefully when considering cannabis prescriptions. “Patients deserve honest conversations about what the science does and doesn't tell us about medical cannabis,” said Hsu. The review recommends screening patients for cardiovascular disease and psychotic disorders, assessing potential drug interactions, and considering whether possible harms outweigh benefits before recommending products containing THC.

The authors also acknowledge important limitations to their research. Their analysis was not a systematic review and did not include a formal risk-of-bias assessment. Some studies were observational and may have been influenced by confounding factors and results may not apply to all patients or cannabis products.

Enthusiasm for the promise of medical cannabis is not evidence. Further research is needed to better understand its benefits and limitations. “By supporting more rigorous studies,” said Hsu, “we can provide clearer guidance and improved clinical care for patients.”

The study is published in JAMA Psychiatry.