5 Findings From The First Major Analysis Of Medical Pot Benefits

CHICAGO (AP) — Medical marijuana has not been proven to work for many illnesses that state laws have approved it for, according to the first comprehensive analysis of research on its potential benefits.

The strongest evidence is for chronic pain and for muscle stiffness in multiple sclerosis, according to the review, which evaluated 79 studies involving more than 6,000 patients. Evidence was weak for many other conditions, including anxiety, sleep disorders, and Tourette’s syndrome and the authors recommend more research.

The analysis is among several medical marijuana articles published Tuesday in the Journal of the American Medical Association. They include a small study suggesting that many brand labels for edible marijuana products list inaccurate amounts of active ingredients. More than half of brands tested had much lower amounts than labeled, meaning users might get no effect.

Highlights from the journal:


The researchers pooled results from studies that tested marijuana against placebos, usual care or no treatment. That’s the most rigorous kind of research but many studies found no conclusive evidence of any benefit. Side effects were common and included dizziness, dry mouth and sleepiness. A less extensive research review in the journal found similar results.

It’s possible medical marijuana could have widespread benefits, but strong evidence from high-quality studies is lacking, authors of both articles say.

“It’s not a wonder drug but it certainly has some potential,” said Dr. Robert Wolff, a co-author and researcher with Kleijnen Systematic Reviews Ltd., a research company in York, England.


Researchers evaluated 47 brands of medical marijuana products, including candy, baked goods and drinks, bought at dispensaries in Los Angeles, San Francisco and Seattle.

Independent laboratory testing for THC, marijuana’s leading active ingredient, found accurate amounts listed on labels for just 13 of 75 products. Almost 1 in 4 had higher amounts than labeled, which could cause ill effects. Most —> Read More