One of the most common arguments I hear against liberalizing our marijuana laws is that marijuana use leads people to use harder drugs like methamphetamine or heroin. The problem with this argument is that it is based mainly on myth and confusion; not backed up by real science.

The gateway theory for marijuana has been around since the 80’s and is based on a research study by Kandel and Yamaguchi showing how early drug use (especially alcohol and tobacco) made people more likely to use harder drugs. “The probabilities of initiating other illicit drug are very much reduced if marijuana is initiated at age 20 or over. . .” Drug warriors took this study out of context and starting saying how marijuana is a “proven” gateway drug, ignoring the authors conclusion pointing out it is the early age of first-use that leads to harder drug use.

With that said, let me point out some of the studies that have shown marijuana is not a gateway drug in and of itself:

From University of Pittsburgh 2006:

Researchers found that adolescents who used marijuana prior to using other drugs, including alcohol and tobacco, were no more likely to develop a substance abuse disorder than other subjects in the study.

From Institute of Medicine 1999:

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

In fact, most drug users begin with alcohol and nicotine before marijuana — usually before they are of legal age.

I’m not saying that people who use marijuana aren’t going to go on and use harder drugs, just pointing out it is not the drug itself causing most of this. There are a variety of studies out there studying the real reasons why some people do use harder drugs, and here are some of their conclusions.

The most common conclusion researchers come to is that using drugs (including alcohol and tobacco) at a young age (younger than 20) greatly increases the probability of moving on to harder drugs, which is what the original gateway theory study said. Another common finding is that exposure to other drugs through buying marijuana on the black market increases the opportunity to use harder drugs. Marijuana is the least profitable currently illegal drug there is (bulky to transport among other things), so drug dealers have an incentive to move users onto harder drugs, especially powder ones (like cocaine and heroin). A less common, but very logical theory is that since marijuana is portrayed as a dangerous drug through the media and programs like DARE, when people use marijuana and nothing bad happens, they begin to doubt anything the government is telling them about drugs.

We really need to start considering alternatives to our current marijuana policies, and our drug policies as a whole. Our policies are based on things like the gateway theory, which have time and time again, been shown to be incorrect. I don’t like the idea of continuing a policy based on wrong information. If you agree, you should sign SSDP’s petition to President-Elect Obama to Reform our Drug Policies

Let me leave you with this tidbit from a Substance Abuse and Mental Health Services Administration report on the issue: youths aged 12-17 who smoked cigarettes in the past month were almost 9 times more likely to use illicit drugs than non cigarette smoking youths. Furthermore, youths aged 12-17 who are considered heavy drinkers were 12 times more likely to use illicit drugs than nondrinkers.

If you would like to see more studies that show marijuana is not a gateway drug and that the gateway theory itself is flawed, go the Gateway Theory page on DrugWarFacts.org.

Tags: gateway drug, gateway theory, marijuana, prohibition