Marijuana: Is it medicine or not?

Americans have a split personality when it comes to marijuana.

A Gallup Poll last October found that support for legalizing marijuana reached an all-time high at 44 percent of the population. But that’s still a minority.

Medical marijuana is quite different. Another Gallup Poll, taken six years ago, showed that 75 percent of adults were in favor of allowing doctors to prescribe the drug for medical purposes. In every category the pollsters measured – from political ideology to age to education – a significant majority were in favor of letting doctors prescribe marijuana to reduce pain and suffering.

Acceptance of medical marijuana, or the possibility that it could be a medicine, continues to grow. The Obama administration’s action last year stopping federal prosecutions of those using the drug for medical reasons where allowed by state law altered the landscape.

Even the American Medical Association shifted its position, voting to study whether the drug should be re-classified from its current Federal Schedule One Controlled Substance classification (potential for high abuse, no legitimate medical use) to promote research into its medical effectiveness. Fourteen states now allow the plant to be grown and used for medical purposes, and five states permit retail pot dispensaries.

The issue has historical and contemporary relevance in Massachusetts. Nearly 20 years ago, the state passed a Controlled Substances Therapeutic Research Act, to allow the Department of Public Health to examine the medical value of marijuana. Conflicts with federal law, however, prevented any research from being conducted.

Now, “The Massachusetts Medical Marijuana Act,” sponsored by a dozen legislators, is pending in the State House.

The purpose of this bill is “to protect patients with debilitating medical conditions, as well as their practitioners and designated caregivers, from arrest and prosecution, criminal and other penalties, and property forfeiture if such patients engage in the medical use of marijuana.” The bill goes so far as to specify the maximum number of plants (24) and usable ounces (8) of marijuana for qualifying patients that a primary caregiver can possess.

The medical marijuana debate continues across the nation. A psychiatrist, arguing in The Wall Street Journal for legalizing pot after New Jersey approved the use of medical marijuana, said the drug “has several unique medical applications” (he didn’t specify what they were) and that for his patients, he’s “more concerned about their consumption of booze than pot.” The New York Times in an editorial on Jan. 13 called New Jersey’s action a “rare piece of good news” and a “show of compassion for the chronically ill.”

Opponents are speaking as well. Skip Miller, an attorney and chairman of D.A.R.E. America, a drug abuse prevention and education program, argued against legalization in the Los Angeles Times, saying that marijuana is “the most commonly abused illicit drug” in the country and “more teens are in treatment for marijuana addiction than for alcohol or any other drug.”

Miller’s words followed a 9-3 vote by the L.A. City Council to limit the number of medical marijuana dispensaries to 70 and restrict their hours. The action would shut most of the shops across the city, now numbering nearly 1,000.  (A University of Michigan survey released in January showed that smoking marijuana among adolescents is more popular than ever, partly because the national debate over medical marijuana makes the drug seem safe.)

Some physicians say evidence is growing that the drug can benefit patients with neuropathic pain or nausea. However, as a clinical oncologist who has treated cancer patients for years and who has reviewed the use of marijuana for medical purposes, I have found little evidence to support marijuana as a medicine.

Two concerns are that clinical research is scant, and no established dosing regimen exists for any condition. I also note that the Food and Drug Administration has approved a synthetic form of medical marijuana, Marinol, available in pill form by prescription.

Support for medical marijuana may be growing, but the risks are high. The drug can lead to abuse and dependency. Marijuana can also affect judgment and inhibit motivation. Used in large amounts, it may cause pulmonary or other medical side effects. It can have psychiatric effects, deepening anxiety and depression and aggravating panic attacks. And it’s often poorly tolerated, especially by older patients.

Also, the percentage of tetrahydrocannibinol (THC) is increasing, as production of the drug becomes more refined to improve its mood-altering effect. Finally, studies have shown that chronic marijuana users have a higher rate of lung cancer than those who smoke tobacco.

The media coverage and the legislative and regulatory debates will continue. Even as more states resolve the legal picture, the medical one remains cloudy and unconvincing. Some may see this as another choice between mainstream medicine and alternative therapies. But physicians, patients, regulators and lawmakers must examine the evidence, calculate the risks versus the rewards, and then ask the important question: Is marijuana really a medicine?

Arthur Skarin, M.D. is president of the Massachusetts Society of Clinical Oncologists.