While medical cannabis is gaining popularity for its supposed benefits, a large-scale synthesis led by experts from UCLA Health questions its real-world effectiveness. This analysis, published in the journal
JAMA, reveals a significant gap between its widespread use and the available scientific data.
This literature review scrutinized more than 2,500 research papers published over a fifteen-year period. The researchers particularly focused on over 120 studies notable for their scope, timeliness, and thematic diversity. Their main finding highlights the growing popularity of cannabis and cannabinoids, such as CBD, while a 2018 survey had already shown that approximately 27% of residents in the United States and Canada used it for health problems.
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Dr. Michael Hsu of UCLA Health, the lead author of the review, notes that many people attribute broad medical benefits to cannabis, while the most recent research does not confirm these expectations. According to him, there is a notable gap between public belief and scientific results, making clear guidance from healthcare professionals essential for informed medical decisions.
The clinically established benefits are limited to a small number of specific conditions. These include pharmaceutical-grade cannabinoid products approved by U.S. health authorities, used to stimulate appetite in HIV/AIDS patients, combat chemotherapy-induced nausea, and treat certain severe forms of childhood epilepsy.
For other uses, such as the management of chronic pain, the data remain insufficient or unclear. Current clinical guidelines, in fact, advise against cannabis-based medications as a first-line treatment for persistent pain, despite its frequent use by more than half of consumers for therapeutic purposes.
Furthermore, the review identifies potential health risks, particularly among adolescents. The use of high-THC cannabis appears linked to an increase in psychotic symptoms and generalized anxiety disorders. Moreover, only 29% of medical-use consumers meet the criteria for a cannabis use disorder.
Additionally, daily consumption, especially in inhaled form or with concentrated products, could be associated with an increased risk of cardiovascular issues. These include higher rates of coronary artery disease, heart attacks, and strokes compared to non-daily use.
How cannabinoids work in the body
Cannabinoids are chemical compounds found in cannabis that interact with our body's endocannabinoid system. This system, present in all mammals, plays a role in regulating various functions such as pain, mood, appetite, and memory.
It consists of receptors, primarily CB1 and CB2, located in the brain, nervous system, and other tissues. Cannabinoids from cannabis, such as THC and CBD, bind to these receptors and modulate their activity, which can produce therapeutic or undesirable effects.
THC, for example, has a high affinity for CB1 receptors, which explains its psychoactive properties and analgesic potential. CBD, on the other hand, acts differently, with little psychoactive effect, and may influence other signaling pathways.
This interaction explains why the effects of cannabis can vary significantly from person to person and why it is difficult to establish universal recommendations. Approved pharmaceutical products attempt to standardize these compounds for precise medical use.