'Much Confusion' About Medical Marijuana


Yesterday, in anticipation of the Supreme Court's imminent decision in Ashcroft v. Raich, the medical marijuana case, The New York Times ran a bizarre story that suggests cannabis is more likely to drive a patient insane than relieve his symptoms. "There remains much confusion over whether marijuana in fact has any significant medical effect," declares Times reporter Dan Hurley. The confusion, it turns out, is mostly in his own mind.

It is beyond serious dispute that marijuana relieves nausea and enhances appetite. Hurley seems unaware of the fact that the FDA has approved Marinol, a capsule containing a synthetic version of THC, marijuana's main active ingredient, for treating AIDS wasting syndrome and the side effects of cancer chemotherapy. When it comes to these and similar uses, the medical question is not whether marijuana works but whether its advantages over Marinol–which include easier absorption, faster action, and better patient control over dose–outweigh the potential respiratory hazards of smoking.

Despite THC's well-established use an anti-emetic, Hurley's story focuses on marijuana's effectiveness in controlling seizures associated with epilepsy and multiple sclerosis, where the evidence is much more limited. He conflates research results in this area, which are promising but preliminary, with the overall case for medicinal use of cannabis. In the third paragraph, for example, Hurley quotes Joseph I. Sirven, an associate professor of neurology at the Mayo Clinic College of Medicine, as saying: "People subjectively report benefits….There's a whole Internet literature suggesting what a wonderful thing [marijuana] is. But the reality is, we don't know." It only gradually becomes clear that Sirven is talking specifically about cannabis in the treatment of epilepsy, not about its overall medical utility.

Hurley tries to minimize the evidence concerning marijuana's effectiveness in relieving nausea and pain by saying it involves "subjective measures"–i.e., patients' reports of nausea and pain. How else would you measure these symptoms? If a randomized trial finds that people who get marijuana are more likely to report decreased nausea or pain than people given a placebo, that's evidence of effectiveness, even though we do not have machines that objectively measure nausea and pain.

Perhaps strangest of all, Hurley early on raises the specter of reefer madness, saying in the fourth paragraph that "a growing body of research indicates that, at least in teenagers, heavy marijuana use over a period of years significantly increases the risk of developing psychosis and schizophrenia." He devotes several more paragraphs to this research before conceding, in the 28th paragraph, that the correlation between heavy pot smoking and psychosis in teenagers is not really relevant to the medical use of marijuana by adult patients. So what is this discussion doing in the article?

While devoting substantial space to a putative hazard that turns out to be a red herring, Hurley does not even mention the government-commissioned report on medical marijuana that the National Academy of Sciences issued in 1999. The report was by no means a ringing endorsement of marijuana as a miracle drug. But after carefully weighing the scientific evidence, it concluded that "the accumulated data indicate a potential therapeutic value for cannabinoid drugs, particularly for symptoms such as pain relief, control of nausea and vomiting, and appetite stimulation." It also noted that, with the exception of the potential respiratory effects of smoking, "the adverse effects of marijuana use are within the range of effects tolerated for other medications."

A careful reporter who was honestly trying to get a handle on marijuana's medical utility would have started with the NAS's thorough assessment and asked experts (including the report's authors) whether and how the evidence has changed in the last five years. For some reason, Hurley went a different way.