Don't Blame Pot -- There's No Such Thing as a "Gateway Drug"

The surging debate surrounding the legalization of marijuana has brought with it the resurrection of the "gateway theory," which alleges that experimenting with marijuana leads to the use of harder drugs like cocaine, heroin and methamphetamine. The gateway debate was reborn last week, thanks to a video of FBI director Robert Mueller testifying before Congress that marijuana should be illegal because it leads to more dangerous drug use.

Although the Mueller video has provoked amusement on pot-friendly websites, the unfortunate reality is that the "gateway drug" stigma continues to present an impediment to the reform of marijuana laws. A new Rasmussen poll found that a large percentage of Americans believe the gateway argument:

The new survey also shows that nearly half of voters (46%) believe marijuana use leads to use of harder drugs. Thirty-seven percent (37%) do not see marijuana as a "gateway" drug.

Revealingly, the percentage who opposed marijuana legalization and the percentage who believed in the gateway theory were identical, both coming in at exactly 46%. As we look for ways to persuade those who remain opposed to marijuana reform, it's clearly in our interest to work towards demolishing the pernicious gateway theory once and for all. Let's take a look at what the data shows.

In 1999, the National Institute on Drug Abuse commissioned a major study on medical marijuana conducted by the venerable Institute of Medicine, which included an examination of marijuana's potential to lead to other drug use. In simple terms, the researchers explained why the gateway theory was unfounded:

Patterns in progression of drug use from adolescence to adulthood are strikingly regular. Because it is the most widely used illicit drug, marijuana is predictably the first illicit drug most people encounter. Not surprisingly, most users of other illicit drugs have used marijuana first. In fact, most drug users begin with alcohol and nicotine before marijuana -- usually before they are of legal age.

…

There is no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other illicit drugs.

In 2006, the University of Pittsburgh released a more thorough study in which researchers spent 12 years tracking a group of subjects from adolescence into adulthood and documented the initiation and progression of their drug use. The researchers found that the gateway theory was not only wrong, but also harmful to properly understanding and addressing drug abuse:

This evidence supports what’s known as the common liability model, an emerging theory that states the likelihood that someone will transition to the use of illegal drugs is determined not by the preceding use of a particular drug but instead by the user’s individual tendencies and environmental circumstances.

“The emphasis on the drugs themselves, rather than other, more important factors that shape a person’s behavior, has been detrimental to drug policy and prevention programs,” Dr. Tarter said. “To become more effective in our efforts to fight drug abuse, we should devote more attention to interventions that address these issues, particularly to parenting skills that shape the child’s behavior as well as peer and neighborhood environments.”

Of course, the simplest refutation of the gateway theory is the basic fact that most marijuana users just don't use other drugs. As the Substance Abuse and Mental Health Services Administration reports:

More than 100 million Americans have tried marijuana; 14.4 million Americans are estimated to be "past-month" users. Yet there are only an estimated 2,075,000 "past-month" users of cocaine and 153,000 "past-month" users of heroin. [DrugWarFacts]