Research on Medical Marijuana

To the Editor: In the June 2012 issue, Drs. Kleber and DuPont (1) conclude that there is no place for medicinal cannabis based on a selected and incomplete review of the data. First, they suggest that evidence for marijuana’s efficacy is anecdotal. This is incorrect. There are results from at least five recent clinical trials reported in peer-reviewed publications (2–6); all of these indicate medicinal cannabis’ efficacy, particularly in the management of neuropathic pain and possibly for multiple sclerosis spasticity. Second, they suggest that medical marijuana laws may lead to increased marijuana abuse as a result of reduced perception of risk. Actually, recent epidemiologic studies concluded that, after adjustment for other factors, such laws had no effect on recreational marijuana consumption (7). Additionally, in their review of the situation in California following passage of Proposition 215, the authors, while correctly pointing to the problems of unregulated dispensaries that followed in its wake, failed to mention a more positive development: California established the Center for Medicinal Cannabis Research at the University of California, the first such center in the nation, to conduct clinical trials to shed light on this topic (http://www.cmcr.ucsd.edu/index.php). Recently, we provided an update on medicinal cannabis research along with a possible algorithm to guide evaluation and decision making by physicians who may be in a position to recommend medicinal cannabis (8).

It is timely to consider the state of the science in medicinal cannabis; however, this needs to be done with full awareness and balanced consideration of all the relevant facts. Hopefully, our letter will facilitate this process by addressing some issues that were missed in the commentary.