A new study has raised serious concerns about the safety and effectiveness of medical cannabis, suggesting that its risks may outweigh any potential benefits. The research, led by Dr. Michael Hsu, an addiction psychiatrist at UCLA, found “insufficient evidence” to support many of the claimed advantages of medical cannabis. This study comes at a time when reliance on marijuana as a treatment for various health issues, including chronic pain and anxiety, is on the rise in the United States, where medical cannabis is legal in 40 states and Washington, D.C.
The comprehensive review analyzed over 2,500 scientific papers published between January 2010 and September 2025. Researchers compared the efficacy of medical cannabis products available at dispensaries with pharmaceutical-grade cannabinoids, which include FDA-approved drugs containing either THC, a psychoactive compound, or CBD, which does not induce a high. The findings revealed that while pharmaceutical-grade medications effectively treat certain conditions such as chemotherapy-induced nausea and vomiting, appetite loss in patients with HIV/AIDS, and severe pediatric seizure disorders, the broader benefits of medical cannabis remain unsubstantiated.
Despite a growing public perception that cannabis can relieve various medical conditions, the study found a significant disconnect between this belief and scientific evidence. For instance, although more than half of medical cannabis users seek relief for acute pain, the research indicated a lack of robust clinical evidence supporting its effectiveness for pain management. Current treatment guidelines do not recommend cannabis-based therapies as a primary option for pain relief.
The review also highlighted weaknesses in the scientific literature regarding medical cannabis for conditions such as insomnia, anxiety, post-traumatic stress disorder (PTSD), Parkinson’s disease, and rheumatoid arthritis. In contrast, the potential dangers of cannabis use were more evident. Long-term studies indicate that adolescents using high-potency cannabis are at an increased risk of experiencing psychotic symptoms, with 12.4% affected compared to 7.1% of those using lower-potency products. Furthermore, the likelihood of developing generalized anxiety disorder was higher among these adolescents, with 19.1% affected versus 11.6% of peers using less potent cannabis.
Approximately 29% of medical cannabis users also meet the criteria for cannabis use disorder, a complex condition characterized by a strong compulsion to use cannabis, increased tolerance, and withdrawal symptoms. Those who begin using cannabis before the age of 18 are particularly vulnerable, facing a four to seven times greater risk of developing dependence compared to adults.
The review further indicated that daily use of medical cannabis—especially inhaled forms or high-potency products—may elevate the risk of cardiovascular issues, including heart attack, stroke, and coronary artery disease, compared to occasional use. In light of these findings, Dr. Hsu and his colleagues advocated for clinicians to screen patients for cardiovascular disease and psychotic disorders prior to recommending THC-containing products.
“Clear guidance from clinicians is essential to support safe, evidence-based decision-making when discussing medical cannabis with their patients,” said Dr. Hsu. The researchers acknowledged limitations in their study, including the absence of a formal risk-of-bias assessment and the reliance on some observational data, which could have been influenced by various confounding factors.
The implications of this study arrive just as discussions intensify regarding potential changes in cannabis classification under federal law. Currently, cannabis is categorized as a Schedule I drug, alongside substances like heroin and LSD. However, speculation is growing that President Trump may consider reclassifying cannabis to Schedule III, which would recognize its medical utility. If this change occurs, it could significantly impact the cannabis market, as evidenced by a surge in cannabis stocks following reports of this potential shift.
Given the complexity of the evidence regarding medical cannabis, Dr. Hsu emphasized the need for further research. “By supporting more rigorous studies, we can provide clearer guidance and improve clinical care for patients,” he stated. As the debate around cannabis continues, the findings of this study underscore the importance of informed conversations between healthcare providers and patients regarding the use of medical cannabis.
