Among the nine behaviors, doctors rated marijuana use as the least-worrisome behavior, tied with abortion as an area of concern. By contrast, doctors rated not wearing a helmet while riding a motorcycle and having intercourse with sex workers several times a year as the most problematic behaviors on the list.
The doctors rated alcohol use, tobacco use and obesity as significantly more pressing issues, health-wise, than marijuana use.
The findings add some empirical heft to a Scientific American essay written by physician Nathaniel Morris, in which he argued that "for most health care providers, marijuana is an afterthought. ... In medicine, marijuana use is often seen on par with tobacco or caffeine consumption — something we counsel patients about stopping or limiting, but nothing urgent to treat or immediately life-threatening."
Although polls show that significant majorities of doctors approve of medical marijuana use, most mainstream medical organizations have been cautious when it comes to changes in marijuana policy. The American Medical Association opposes marijuana legalization, for instance.
But as more states liberalize their marijuana policies, some doctors' groups are adopting an official pro-legalization stance. The California Medical Association supports the ballot measure that would legalize the recreational use of marijuana there. Earlier this year, a group of physicians calling themselves Doctors for Cannabis Regulation formed with the explicit goal of supporting marijuana legalization on public health grounds.
As for the political distinction that was the reason these questions were posed in the first place, the PNAS study found that marijuana use was one of the more polarizing topics among the doctors they surveyed. Republican doctors were, on average, much more concerned about marijuana use than their Democratic colleagues.
"Republican [physicians] are more likely to discuss health risks of marijuana [with their patients], urge the patient to cut down, and discuss legal risks," according to the study.
The doctors were also polarized over the relative seriousness of previous abortions (Republican doctors more concerned) and of the presence of guns in the home (Democratic doctors more concerned).
Overall, doctors' mild concern about marijuana use is not terribly surprising, given what the research shows about the health risks of marijuana use relative to the use of other common drugs, such as alcohol and tobacco.
Public health-wise, most researchers aren't worried about marijuana use per se, but rather heavy marijuana use -- the people who use marijuana daily, or multiple times a day. Those people are at a greatest risk for dependency and various health problems associated with heavy use -- even if those problems don't appear to be as severe as the debilitating conditions associated with long-term heavy tobacco or alcohol use.