Medical Marijuana Has Merit, Research Shows
Although Research Shows Medical Mariuana Works, Critics Say California Center's Research Is Flawed
Feb. 18, 2010 -- Marijuana can be a promising treatment for some
specific, pain-related medical conditions, according to California
researchers who presented an update of their findings Wednesday to the
California Legislature and also released them to the public.
''I think the evidence is getting better and better that marijuana, or the
constituents of cannabis, are useful at least in the adjunctive treatment of neuropathy," Igor Grant, MD, executive vice-chairman of
the department of psychiatry at the University of California San Diego
School of Medicine and director of the Center for Medicinal Cannabis Research
at the University of California, tells WebMD.
''We don't know if it's a front-line treatment. I'm hoping the results of
our studies will prompt larger-scale studies that involve a much more varied
''This [report given to the Legislature] sets the stage of larger-scale
studies,'' he says.
Some experts who reviewed the report say some of the studies are flawed and
that they worry about the long-term health effects of marijuana smoke.
Perspective: Medical Marijuana Research
Some observers speculated that the researchers presented their report to the
Legislature to call attention to marijuana research because an initiative to
legalize marijuana for general use is expected to be on the California ballot
in November 2010.
But Grant says that's not the case. "We sent it to the Legislature because
our report was due," he says.
The program Grant directs was launched in 1999, when the California
Legislature passed (and the governor signed) SB 847. Since then, the center has
completed five scientific trials, with more in progress.
Medical Marijuana: The Research Scorecard
Five studies, published in peer-reviewed medical journals, show the value of
marijuana for pain-related conditions, the researchers say in the report.
- Smoked cannabis reduced pain in HIV
patients. In one study, 50 patients assigned either to cannabis or placebo
finished the study. Although 52% of those who smoked marijuana had a 30% or
more reduction in pain intensity, just 24% of those in the placebo group did.
The study is published in the journal Neurology. In another study, 28
HIV patients were assigned to either marijuana or placebo -- and 46% of pot
smokers compared to 18% of the placebo group reported 30% or more pain relief.
That study is in Neuropsychopharmacology.
- Marijuana helped reduce pain in people suffering spinal cord injury and
other conditions. In this study, 38 patients smoked either high-dose or
low-dose marijuana; 32 finished all three sessions. Both doses reduced
neuropathic pain from different causes. Results appear in the Journal of
- Medium doses of marijuana can reduce pain perception, another study found.
Fifteen healthy volunteers smoked a low, medium, or high dose of marijuana to
see if it could counteract the pain produced by an injection of capsaicin, the ''hot'' ingredient in chili peppers. The
higher the dose, the greater the pain relief. The study was published in
- Vaporized marijuana can be safe, other research found. In this study, 14
volunteers were assigned to get low, medium, or high doses of pot, either
smoked or by vaporization delivery, on six different occasions. The vaporized
method was found safe; patients preferred it to smoking. The study is in Clinical Pharmacology &
A sixth study, as yet unpublished, found marijuana better than placebo
cigarettes in reducing the spasticity associated with multiple
sclerosis and the pain associated with the spasticity.