Pubdate: Fri, 26 Jun 2015
Source: Arizona Republic (Phoenix, AZ)
Copyright: 2015 Associated Press
Contact: http://www.azcentral.com/arizonarepublic/opinions/sendaletter.html
Website: http://www.azcentral.com/arizonarepublic/
Details: http://www.mapinc.org/media/24
Author: Lindsey Tanner, Associated Press

STUDY QUESTIONS IF MARIJUANA EFFECTIVE FOR MANY CONDITIONS

CHICAGO (AP) - Medical marijuana hasn't been proved 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.

The analysis is among several medical marijuana articles published 
Tuesday in the Journal of the American Medical Association. They 
include a small study suggesting 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 may get no effect.

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 had lower-than-listed amounts. There were similar findings for 
another active ingredient. Products were not identified by name.

Johns Hopkins University researcher Ryan Vandrey, the lead author, 
said he was surprised so many labels were inaccurate. The researchers 
note the results may not be the same in other locations.

Twenty-three states and Washington, D.C. have laws permitting medical 
marijuana use. Approved conditions vary but include Alzheimer's 
disease, epilepsy, glaucoma, kidney disease, lupus and Parkinson's disease.

An editorial in the journal says approval in many states has been 
based on poor quality studies, patients' testimonials or other 
nonscientific evidence.

The editorial by two Yale University psychiatrists suggests 
enthusiasm for medical marijuana has outpaced rigorous research and 
says widespread use should wait for better evidence. Federal and 
state governments should support and encourage such research, the 
editorial says.

The psychiatrists note repeated recreational marijuana use can be 
addictive and say questions remain about the long term health effects 
of medical marijuana use and whether its use is justified in children 
whose developing brains may be more vulnerable to its effects.
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