High hopes for medical cannabis are going up in smoke.
A bombshell new report found “insufficient evidence” to back up most of its supposed benefits — and raised serious red flags about hidden risks.
“Patients deserve honest conversations about what the science does and doesn’t tell us about medical cannabis,” Dr. Michael Hsu, an addiction psychiatrist at UCLA and lead author of the study, said in a statement.
The findings come as Americans increasingly rely on marijuana to cope with chronic pain, sleep difficulties, anxiety and a wide range of other health concerns.
Medical cannabis is now legal in 40 states and DC, and nearly 9 in 10 US adults say they support using it when prescribed by a doctor.
“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 said.
In the sweeping review, Hsu and his colleagues analyzed more than 2,500 scientific papers published between January 2010 and September 2025.
They compared medical cannabis sold at dispensaries with pharmaceutical-grade cannabinoids — the handful of FDA-approved drugs containing either THC, a psychoactive compound, or CBD, which doesn’t cause a high.
The researchers found these medications delivered real benefits for chemotherapy-induced nausea and vomiting, boosting weight in patients with HIV/AIDS-related appetite loss and easing certain severe pediatric seizure disorders.
But the science-backed benefits for medical cannabis fell short of the public hype.
Even though more than half of users try it for acute pain, Hsu and his team found no solid clinical evidence that it works. Current guidelines don’t recommend cannabis-based treatments as a first-line option for pain management.
They also found that research on medical cannabis for conditions such as insomnia, anxiety, PTSD, Parkinson’s disease, and rheumatoid arthritis was weak or inconclusive at best.
When it came to potential dangers, however, the risk was clear.
Long-term studies suggest that adolescents using high-potency cannabis face higher rates of psychotic symptoms, with 12.4% affected compared with 7.1% of those using low-potency products.
They were also more likely to develop generalized anxiety disorder, with 19.1% experiencing it versus 11.6% of their peers using weaker cannabis.
Notably, the researchers found that about 29% of medical cannabis users also meet the criteria for cannabis use disorder.
This complex psychiatric condition typically involves a strong, compulsive urge to use cannabis, increased tolerance and withdrawal symptoms when use stops, according to the Cleveland Clinic.
Cannabis use disorder primarily involves THC-containing products. The risk is higher for those who start using before age 18, who are four to seven times more likely to develop the dependence than adults.
The review also found that daily use of medical cannabis — especially inhaled or high-potency products — may increase the risk of cardiovascular problems compared with occasional use. That includes a higher chance of heart attack, stroke and coronary artery disease.
In light of the findings, Hsu and his colleagues recommended that doctors screen patients for cardiovascular disease and psychotic disorders before suggesting they try THC-containing products.
They also urged physicians to consider potential drug interactions and weigh the possible harms against the benefits when deciding whether to prescribe medical cannabis.
“Clear guidance from clinicians is essential to support safe, evidence-based decision-making when discussing medical cannabis with their patients,” Hsu said.
The researchers acknowledged several limitations, noting that the study wasn’t a systematic review and didn’t include a formal risk-of-bias assessment.
They also pointed out that some of the research was observational and could have been influenced by confounding factors. The findings may not apply to every patient due to differences in study design, the cannabis products tested, and participant characteristics.
“Further research is crucial to better understand the potential benefits and risks of medical cannabis,” Hsu said. “By supporting more rigorous studies, we can provide clearer guidance and improve clinical care for patients.”
The findings come as speculation grows that President Trump may soon reclassify cannabis under federal law.
Aside from the FDA-approved prescription medications, the federal government still lists cannabis as a Schedule I drug — the same category as heroin and LSD.
That could soon change. Cannabis stocks surged on Friday amid reports that Trump plans to move it to Schedule III, a step that would acknowledge marijuana as less dangerous and acceptable for medical use.
