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Medical marijuana science, through the smoke

Support for medical use of cannabis is growing; research is mostly favorable, but there is some caution.

July 20, 2009|Judy Foreman

Marcy Duda, a former home health aide with four children and two granddaughters, never dreamed she'd be publicly touting the medical benefits of pot.

But marijuana, says the 48-year-old Ware, Mass., resident, is the only thing that even begins to control the migraine headaches that plague her nine days a month, which she describes as feeling like "hot, hot ice picks in the left side of my head."

Duda has always had migraines. But they got much worse 10 years ago after two operations to remove life-threatening aneurysms, weak areas in the blood vessels in her brain. None of the standard drugs her doctors prescribe help much with her post-surgical symptoms, which include nausea, vomiting, loss of appetite and pain on her left side "as if my body were cut in half."

With marijuana, however, "I can at least leave the dark room," she says, "and it makes me eat a lot of food."

The culture wars over marijuana, for recreational and medical use, have been simmering for decades, with marijuana (cannabis) still classified, like heroin, as a Schedule I controlled substance by the U.S. government, meaning it has no approved medical use. (There is a government-approved synthetic form of marijuana called Marinol available as a prescription pill for treating nausea, vomiting and loss of appetite, though advocates of the natural stuff say it is not as effective as smoked pot.)

Some critics of marijuana use, such as David Evans, special advisor to the Drug Free America Foundation of St. Petersburg, Fla., applaud the government's view, saying marijuana has not gone through a rigorous U.S. Food and Drug Administration approval process.

But that skepticism frustrates leading marijuana researchers such as Dr. Donald Abrams, a cancer specialist at San Francisco General Hospital.

"Every day I see people with nausea secondary to chemotherapy, depression, trouble sleeping, pain," he says. "I can recommend one drug [marijuana] for all those things, as opposed to writing five different prescriptions."

The tide seems to be turning in favor of wider medical use of marijuana. The Obama administration announced in March that it will end the Bush administration's practice of frequently raiding distributors of medical marijuana. Thirteen states, including California, Vermont, Rhode Island and Maine, now allow medical use of marijuana, according to Bruce Mirken, spokesman for the Marijuana Policy Project, which advocates legalization of pot. Earlier this month, however, New Hampshire Gov. John Lynch vetoed legislation that would have legalized medical marijuana in that state.

A growing body of research supports the drug's medical usage, but some of it is cautionary. As Abrams puts it, "you can find anything you want in the medical literature about what marijuana does and doesn't do."

With that in mind, here's an overview of what the research says about the safety and effectiveness of using marijuana to treat various ailments.

Pain: Marijuana has been shown effective against various forms of severe, chronic pain. Some research suggests it helps with migraines, cluster headaches and the pain from fibromyalgia and irritable bowel syndrome because these problems can be triggered by an underlying deficiency in the brain of naturally occurring cannabinoids, ingredients in marijuana. Smoked pot also proved better than placebo cigarettes at relieving nerve pain in HIV patients, according to two recent studies by California researchers.

Marijuana also seems to be effective against nerve pain that is resistant to opiates.

Cancer: The active ingredients in cannabis have been shown to combat pain, nausea and loss of appetite in cancer patients, as well as block tumor growth in lab animals, according to a review article in the journal Nature in October 2003. But there's vigorous debate about whether smoking marijuana increases cancer risk.

Some studies that have looked for a link between cancer risk and marijuana have failed to find one, including a key paper from UCLA published in 2006. "We had hypothesized, based on prior laboratory evidence, including animal studies, that long-term heavy use of marijuana would increase the risk of lung and head and neck cancers," said Hal Morgenstern, a co-author and an epidemiologist at the University of Michigan School of Public Health. "But we didn't get any evidence of that, once we controlled for confounding factors, especially cigarette smoking."

But in California, the first state to legalize marijuana for medical use, in 1996, the Office of Environmental Health Hazard Assessment recently declared pot smoke (though not the plant itself) a carcinogen because it has some of the same harmful substances as tobacco smoke.

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