Medical Marijuana: An Oxymoron?
Has public opinion trumped the rigors of the scientific method – clinically sound research that supports or negates the efficacy of marijuana for medical use?
A recent issue of the Journal of the American Medical Association (JAMA) devoted two extensive clinical reviews, a research letter, an editorial and a patient page to topics related to medical marijuana. The reviews lay bare what is at the heart of the medical marijuana debate for the health care industry: Has public opinion trumped the rigors of the scientific method – clinically sound research that supports or negates the efficacy of marijuana for medical use?
There are downstream effects of the legalization of medical marijuana that are not specifically related to efficacy or safety. On the legal side, they point out that legalization by 23 states and the District of Columbia does not trump federal prohibition – a point brought home by a recent Colorado case in which the court decision favored a “no tolerance” employer’s right to fire an employee for testing positive, even with the foreknowledge of the employee’s medical use. This decision has implications for physicians who might certify patients for medical use, liability carriers who might cover such physicians, and the more general issue of liability for harm referent to certified use.
A little background
Most people are not aware of the nuts-and-bolts questions behind the legalization of medical marijuana. Important related questions include:
Q: Why do physicians “certify” rather than prescribe?
A: Because marijuana is not FDA-approved for any medical condition
Q: And, why not?
A: Because no one has applied to the FDA with at least two adequately powered randomized clinical trials in support of marijuana’s use for any specific medical condition
Q: So how did states decide to legalize, and for what conditions?
A: States relied on low-quality evidence, public opinion, testimonials and anecdote; the choice of conditions to cover was equally idiosyncratic, with contiguous states certifying disparate conditions with little scientific evidence.
A higher standard not being upheld
We should only hope the FDA never falls to these standards. A related concern is the lack of oversight and labeling accuracy. Not only is the makeup of marijuana very complex (>400 possibly active compounds including ~70 non-THC cannabinoids), but there are no dosing guidelines, product consistency, or demonstrated labeling accuracy. Vandrey et al. tested edible cannabis products from three large metropolitan areas and found that the majority failed to meet pharmaceutical labeling standards, with the amount of THC significantly overstated by more than half, understated by roughly a quarter, and some products having barely or undetectable levels. THC is not the only active, and presumably effective, cannabinoid. Another significant cannabinoid, CBD, is equally effective without intoxicating effects, with research suggesting an optimal THC:CBD ratio of 1:1. Only one of 75 tested edibles had this 1:1 ratio, and many did not label the CBD content at all. As with many unregulated supplements, it is hard to medically recommend products with no quality control.
Such limited efficacy, with increased risk of short-term adverse effects, unknown effects of chronic use, and the more lasting deleterious effects on brain development (which continues through age 25) speaks to the need for more and better research before jumping on this bandwagon.
The meat of the efficacy issue, however, lies in the rigorous clinical review and meta-analysis of the studies: randomized clinical trials of cannabinoids for chemotherapy-related nausea and vomiting, appetite stimulation in patients with HIV/AIDS, chronic pain, spasticity from MS or paraplegia, depression, anxiety, psychosis, sleep disorder, glaucoma or Tourette syndrome. Only chronic pain and spasticity were found to have moderate-quality evidence in support of cannabinoids. Such limited efficacy, with increased risk of short-term adverse effects, unknown effects of chronic use, and the more lasting deleterious effects on brain development (which continues through age 25) speaks to the need for more and better research before jumping on this bandwagon.
Regardless of what side of the bench one stands in the medical marijuana debate, it is not in the interest of any of us to let the tide of public opinion undermine the value of the scientific method in determining what is, in fact, best. Opinion has no place in determining the health of our nation. Evidence does.
If you were to read one concise, well-considered summary on this topic, I would recommend the editorial by D’Souza and Ranganathan.