I often hear people say that marijuana (as contrasted to tobacco and alcohol) “has never killed anyone.” The editorial page on March 2 had a cartoon expressing this point of view.

Evidence for the falsity of this argument has been available for years. This is similar to the long path that we took in helping people to understand how harmful tobacco can be. Before the Surgeon General’s Report in the early 1960s, tobacco smoking was widespread and tobacco companies touted the health benefits of their cigarettes.

A metareview of marijuana research, “Marijuana and Lung Diseases,” can be found in Medscape Week in Review.

The authors say marijuana does have medical benefits, especially when taken in ways that do not involve smoking. Regular recreational use, however, has respiratory risks, especially for chronic bronchitis and possibly for lung cancer. Cannabis has been found to shrink cancer cells in petri dishes but produce pre-cancerous changes in the respiratory tract of smokers. So, it may be the smoking (and the carcinogens that are delivered along with THC) that constitute the risk for recreational smokers.

Finally, as a licensed alcohol and drug counselor, many clients have told me marijuana does not impair driving. A 2012 study in the British Medical Journal, however, indicates that marijuana intoxication “can lead to impairment of cognition, coordination and judgment and can result in automobile accidents (and) … nearly doubles the risk of a collision resulting in serious injury or death.”

The issues of medical marijuana and legalization are complex. Though legalization ultimately may be the best solution when all factors are weighed, we must not forget this choice is a risky one both in terms of long-term health consequences and what may happen to our community with one more intoxicant widely disseminated and widely used.

David DoreauWaterville