As part of a “Room for Debate” series on how to sell marijuana safely, psychiatry professor A. Eden Evins spells out the risks for stoners:

Regular cannabis use has been associated with an 8- to 10-point drop in I.Q. over the course of 20 years, a change that would bring one from the 50th percentile to just over the 30th. Again, those who started regular use in adolescence experienced greater I.Q. decline than those who started as adults. Marijuana worsens cognitive performance, particularly in the domains of verbal learning, verbal working memory and attention accuracy. Some deficits appear to be lasting. Attention accuracy deficits associated with cannabis use do not improve with abstinence. These results suggest hippocampal, subcortical and prefrontal cortex abnormalities, some of which may be lasting.

As usual, these potential drawbacks are never related to the drawbacks of many other legal substances, like, say tobacco or alcohol. In fact, our public discussion of these pleasures almost never focuses on their potential harm. Alcohol clearly does far more harm to people than marijuana. It foments violence, can destroy the liver, breaks up families and is far more addictive than pot. So let’s see how the same newspaper, the New York Times, covers those risks:

Sipping a good gin and tonic is like finding a 20th-century oxford shirt in the closet and realizing that you can still wear it downtown tonight without looking out of step with the century we’re stuck in. It just works. But that hasn’t stopped mixology-besotted bartenders from trying to make it better. You’ll find a few of them who can’t resist filling a glass with more and more flavor dimensions, creating a gin and tonic that’s such a complicated spectacle, you barely recognize it. The good news, though, is that plenty of fresh and successful variations are being dreamed up by bartenders and restaurateurs who don’t view the word “restraint” as an epithet.

Notice how “restraint” is clearly here a negative notion. So you have the same newspaper celebrating the lack of restraint for a form of alcohol that once turned London into a chaotic, crime-ridden, besotted mess (see above), while noting small, long-term effects for a much safer form of recreational release. I’m all for weighing the costs of smoking or inhaling cannabis. We should be aware that, like all substances, it can give pleasure and also physical or mental harm. But when it is singled out for obloquy in the same space that a far more dangerous drug is not just celebrated but lionized, something other than science is at work.

(Illustration: Gin Lane by Hogarth, 1751.)