Many young adults remember their childhood participation in Drug Abuse Resistance Education, better known by the acronym "D.A.R.E." One of the program's core messages—along with the idea that you should always shout "NO!" when offered some "really cool drugs to smoke"—is that marijuana is a "gateway" to all sorts of other substances.
D.A.R.E's effectiveness was later called into question, and its curriculum overhauled, but the legend remains: One toke, and before long you're living a less-accented version of Trainspotting.
“Marijuana is a gateway drug,” New Jersey governor Chris Christie told a radio host recently. "I just think it's a slippery slope," Boston Mayor Marty Walsh warned reporters last year. Even D.A.R.E. is back in the game, publishing a blog post last year with the headline, "Marijuana a risky gateway drug, experts say."
But is weed really a causal precursor, a pit-stop on the road to cocaine and heroin?
The people behind Treatment4Addiction, a website for finding addiction treatment, recently parsed the data from the 2012 National Survey on Drug Use and Health to see which drugs people tried right before and after they started using a given narcotic. (Click the boxes at the left to highlight a drug. The diagonal lines leading up to it show the percentage of people who tried a given substance immediately before that drug. The lines to the right show the drugs they tried right after.)
Marijuana does, at first, look like somewhat of a gateway: It pops up relatively early in a drug user's experience and is often chased by other substances. A fifth of weed smokers had never tried a different drug before, and two-thirds of them had only ever drank. Sixty percent of pot smokers go on to try another drug right afterward. (Still, for 17 percent of them, that drug is alcohol.)