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Massachusetts Medical Society's Physician Focus

September 2014

Is Marijuana Medicine?


  • Massachusetts and nearly 25 other states have approved the use of marijuana as medicine.

  • The drug is still an illegal substance according to Federal law, classified as having a high potential for abuse and no medical benefit.

  • While it appears to have some medicinal benefit, the research clearly shows that chronic use of marijuana is harmful.

  • Whatever role marijuana may have as a medicine, physicians say it should not be a first-line therapy for any condition.

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Despite a ban by the Federal government, little clinical research into its effectiveness as a medicine, and lack of approval by the Food and Drug Administration, the use of marijuana for medical purposes has been approved by nearly 25 states. More are likely to follow.

In Massachusetts, voters in 2012 overwhelmingly approved a ballot question allowing the use of marijuana by patients with “debilitating medical conditions.” The vote represented a major departure from the nation’s usual way of creating, testing, and approving medicines: well-controlled, sanctioned clinical trials and review and approval by the U.S. Food and Drug Administration.

Given the public’s approval of this drug as medicine and the impending opening of marijuana dispensaries in the Commonwealth, Physician Focus invited two physicians knowledgeable about marijuana for its September episode to discuss a basic question: Is marijuana medicine?

Alan Ehrlich, M.D., Senior Deputy Editor of DynaMed, a clinical reference tool created by physicians that examines medical articles for clinical relevance and scientific validity, and Kevin Hill, M.D., Director of the Substance Abuse Consultation Service in the Division of Alcohol and Drug Abuse at McLean Hospital in Belmont, joined program host John Fromson, M.D., Chief of Psychiatry at Brigham and Women’s Faulkner Hospital in Boston for the program. The three examined the current evidence surrounding marijuana and what patients should know about it if they are considering it for medicinal purposes.

Some history is relevant here. Prompted by abuse of the drug, the U.S. Government banned marijuana in the 1930s, a ban that remains to this day. The U.S. Controlled Substances Act now lists marijuana as a Schedule I drug, regarding it as having a high potential for abuse and no currently accepted medical use in treatment in the United States.

“Because of the classification,” says Dr. Ehrlich, “there are not a lot of studies that involve the marijuana plant itself, whether it be smoked, ingested, or taken in some other form. With so few studies, it’s hard to draw sound conclusions about its medical use.”

What is certain is that marijuana is the most commonly used illicit drug in the U.S., and while many believe it to be safer than tobacco and alcohol, the physicians say the research clearly shows that marijuana can be harmful.

Dr. Hill notes that it may worsen anxiety and depression, induce psychosis, and cause cognitive difficulties because of its effects on the brain, especially in adolescents and young adults whose brains are still developing.

“The majority of people who use marijuana, like alcohol,” says Dr. Hill, “don’t become addicted. Only 9 percent of adult users and 16 percent of teenagers do. Yet because more people use marijuana than any other drug – more than 18 million in the U.S. – a small fraction of a large number can be a very large number.”

“There are clear harms associated with the chronic use of marijuana,” says Dr. Ehrlich. “Just because it may be less severe than some of those other things [alcohol, tobacco] doesn’t mean it’s completely safe or without adverse effects.”

The physicians do say that marijuana may help with symptoms of some conditions, such as spasticity (spasms) associated with multiple sclerosis, pain from neuropathy, or nausea or vomiting from chemotherapy. But they caution that whatever role marijuana may play as medicine, it should be as a supplement to standard treatment. “There isn’t any condition,” says Dr. Ehrlich, “for which your first line of therapy should be marijuana.”

How much of it to use is also a concern. “Dosage is tricky,” says Dr. Hill. “It all depends on the concentration. There are no set guidelines for dosage.” He adds that different strains have different concentrations of THC (tetrahydrocannabidinol), the active ingredient in the drug that gives it its narcotic and psychoactive effects. In all, marijuana has more than 60 active ingredients called cannabinoids, and a few of those have been approved in pill form by the FDA for treatment of a few conditions.

For those patients considering using marijuana as medicine, the physicians advise first talking with a doctor who knows them well. (Massachusetts regulations require that patients be certified by a physician with whom they have an on-going relationship to obtain medical marijuana.) There are no approved standards of care with regard to marijuana’s use as medicine.

“Whoever you have your best relationship with for the disease you’re thinking about,” says Dr. Ehrlich, “that is the person you should be talking to.”

Watch the video above for additional discussion about different kinds of cannabinoids, the conditions marijuana may help, its impact on patients of different ages, withdrawal symptoms from chronic use, and the risks of using the drug.

MMS/Richard Gulla

Massachusetts Department of Public Health
Information about the Medical Marijuana Program in the Commonwealth

Drug Facts: Is Marijuana Medicine?
Drug facts about marijuana including its use for medicinal purposes from the National Institutes of Health/National Institute on Drug Abuse

Additional Videos Featuring This Program’s Guests
From the Massachusetts Medical Society’s Continuing Medical Education Program,
Medical Marijuana: Regulations, Responsibilities and Communication, June 18, 2014

Medical Marijuana: An Evidence-Based Assessment of Efficacy and Harms
Alan M. Ehrlich, M.D., Senior Deputy Editor, DynaMed, EBSCO Publishing; Assistant Professor of Family Medicine, University of Massachusetts Medical School

Video Presentation of 39:15; Slide Presentation of 26 pages

Medical Marijuana in the Commonwealth: What a Physician Needs to Know
Kevin P. Hill, M.D., M.H.S., Director, Substance Abuse Consultation Service, Division of Alcohol and Drug Abuse, McLean Hospital; Assistant Professor of Psychiatry, Harvard Medical School

Video Presentation of 39:16; Slide Presentation of 31 pages

From left, John Fromson, M.D., Alan Ehrlich, M.D., Kevin Hill, M.D.
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