Probing Question: Is medical marijuana a medically valid treatment?

Dan Shapiro was 20 years old when doctors found a tumor the size of a grapefruit growing inside his chest. He was immediately prescribed an aggressive course of chemotherapy, but the drugs made him miserably sick and none of the anti-nausea medications available at the time helped. That's when his mother—normally a law-abiding citizen—planted a small crop of marijuana in the middle of her suburban garden. "The weed worked," says Shapiro, a Penn State professor of psychiatry and author of the 2001 book Mom's Marijuana. "I was far less nauseous, and I didn't vomit."

marijuana in pill bottle

Though native cultures around the globe have long used it as a folk remedy, the value of marijuana—the common name of the flowering herb, Cannabis sativa—has been the subject of vigorous debate within Western medicine. Does the plant belong on the shelves next to legitimate drugs, like morphine, Vicodin, and Oxycontin? Is marijuana ever a medically valid treatment?

Shapiro thinks so. "Physicians prescribe more dangerous, addictive, and mind-altering drugs than marijuana all the time," he says. "So why shouldn't they be able to prescribe marijuana, which is nearly impossible to overdose on? Marijuana is hardly a panacea, but the evidence for its benefits is solid enough that it should be allowed to be legally prescribed."

Indeed, the medical benefits surfacing in the scientific literature are numerous. According to Michael Green, a Penn State professor of humanities and medicine and an expert on medical ethics, "There are many reports, some scientific and some anecdotal, of the medical benefits of marijuana, including its ability to reduce nausea and vomiting, stop unintentional weight loss among HIV patients, lessen memory loss among people with Alzheimer's disease, relieve certain symptoms of multiple sclerosis, and ease eye pressure associated with glaucoma."

Marijuana is currently illegal at the federal level and classified as a Schedule I controlled substance, which means that the federal government views it as highly addictive, with no officially accepted medicinal uses, and no safe level of use under medical supervision. Heroin, LSD, and peyote are other Schedule I drugs. By contrast, Schedule II drugs—including cocaine, morphine and oxycodone—are classified as having "safe and accepted medical uses" and doctors are allowed to prescribe them. (Cocaine is described as a topical anesthetic.)

On the state level, it's quite a different story. Medical marijuana has been legalized in 14 states, each of which has its own laws regarding the particular ailments for which the drug can be prescribed and how patients can obtain and possess the drug. These laws vary tremendously, depending on geography. For example, patients in Alaska legally can possess no more than one ounce of marijuana, while patients in Oregon can possess up to 24 ounces. (Regarding "recreational" marijuana, consequences of possession are equally varied among states. In Florida, being caught with an ounce of marijuana could get you 5 years behind bars and a $5,000 fine, whereas in Ohio, it's a minor misdemeanor with a $100 fine, and in Alaska it's legal.)

In most states, patients are allowed to grow their own plants, and some states have made it even easier by legalizing marijuana dispensaries. This "cannabusiness"—a colloquial term for the medical marijuana industry—is proving to be a financial windfall. For instance, California's medical marijuana industry earns about $2 billion a year.

With so many documented benefits and with nearly a third of all states already signed on, why hasn't the rest of the country gone the way of the weed?

Green thinks that many people are opposed to medical marijuana because of the stigma attached to the drug (think Cheech and Chong). "There is a lot of baggage associated with marijuana that has nothing to do with its medical uses," he says, noting that some people raise concerns that patients will use their illness as an excuse to abuse the drug.

Green—who personally doesn't have a problem with the use of medical marijuana when no better alternatives are available—says laws that restrict individual freedoms are generally to be avoided, but may be justified when they prevent harm to others or to society in general. "It is unlikely that a cancer patient who uses marijuana causes harm to others," he says, "and it's debatable whether that use causes harm to the patient him- or herself. But even if medical marijuana has the potential to cause harm, in the medical context, competent adults are typically permitted to decide for themselves whether the harms are outweighed by potential benefits, and then to make their own informed decisions about it."

Whether or not to legalize marijuana is a complex and emotionally charged issue. "In my opinion," says Shapiro, "marijuana is neither the monster anti-drug crusaders would have us believe, nor the innocuous panacea pro-legalization folks favor. It is a drug with potentially troubling side effects that can be useful for a limited number of conditions."

Michael Green, M.D., M.S., is Professor of Humanities and Medicine and Director of the Bioethics Program at the Penn State College of Medicine and can be reached at Dan Shapiro, Ph.D., is Professor and Chair of the Humanities Department at Penn State College of Medicine and can be reached at

Last Updated November 06, 2010