WeeklySA_AdminSCIENTIFIC: A sweeping analysis of more than 2,500 studies finds limited proof that medical cannabis helps most conditions it’s commonly used for — despite rising global acceptance and popularity…
By Weekly SA Reporter
Medical cannabis remains widely used globally, but scientific evidence supporting many of its popular medical applications is still limited.
This is according to a major review published in JAMA and led by UCLA Health, which examined more than 2 500 studies published between January 2010 and September 2025.
The researchers prioritised over 120 robust studies — including randomized clinical trials, meta-analyses and clinical guidelines — to assess the strength of evidence behind cannabis-based treatments. Their conclusion: despite growing consumer enthusiasm, the scientific case for medical cannabis remains weak for most conditions, particularly chronic pain, anxiety and insomnia.
Lead author Dr Michael Hsu of UCLA Health noted a widening disconnect between what the public believes cannabis can treat and what science has confirmed. “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,” said Hsu, a clinical assistant professor in the Department of Psychiatry and Biobehavioral Sciences.
He stressed the need for clinicians to provide clear, evidence-based guidance as cannabis continues to be marketed for a wide array of ailments.
The review affirmed that FDA-approved cannabinoid medications do offer proven benefits, but in a very narrow set of conditions. These include:
• Appetite loss related to HIV/AIDS;
• Chemotherapy-induced nausea and vomiting; and
• Severe paediatric seizure disorders, including Dravet syndrome and Lennox-Gastaut syndrome.
However, the evidence for many other frequently cited uses — especially chronic pain — remains inconclusive. Despite more than half of medical cannabis users reporting pain relief as their primary reason for use, current clinical guidelines do not recommend cannabis-based medicines as a first-line treatment.
The researchers also flagged several safety concerns. Data from adolescent studies indicate that high-potency cannabis may increase the risk of psychotic symptoms (12.4% compared to 7.1% for low-potency users) and generalized anxiety disorder (19.1% versus 11.6%).
Worryingly, 29% of people who use medical cannabis meet the criteria for cannabis use disorder.
Daily use — especially of inhaled or high-potency products — may elevate cardiovascular risks such as coronary heart disease, heart attack and stroke. The review advises clinicians to screen patients for heart conditions, psychotic disorders, potential drug interactions and overall risk-benefit balance before recommending THC-containing products.
“Patients deserve honest conversations about what the science does and doesn’t tell us about medical cannabis,” Hsu added.
The authors caution that the review is not a systematic review and lacks a formal risk-of-bias assessment. Many included studies were observational and may be affected by confounding variables. Moreover, results from clinical trials may not apply broadly due to varying formulations, potencies and patient characteristics.
Co-authors from Harvard, UC San Francisco, Washington University School of Medicine and New York University agreed that more rigorous studies are essential. “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”. – Science X
