Why Smoking Medical Marijuana 
Cannabis Doesn't Make You a Junkie

Two recent studies should be the final nails in the
coffin of the lie that has propelled some of this
nation's most misguided policies: the claim that
smoking marijuana somehow causes people to 
use harder drugs, often called the "Gateway Theory."

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Such claims have been a staple of the White House
Office of National Drug Control Policy under present
drug czar John Walters. Typical is a 2004 New Mexico
speech in which, according to the Albuquerque Journal,
"Walters emphasized that marijuana is a 'gateway drug'
that can lead to other chemical dependencies."

The gateway theory presents drug use as a tidy
progression in which users move from legal drugs like
alcohol and tobacco to marijuana, and from there to
hard drugs like cocaine, heroin and methamphetamine.
Thus, zealots like Walters warn, marijuana is bad
because it leads to things that are even worse.

It's a neat theory, easy to sell. The problem is,
scientists keep poking holes in it -- the two new
studies being are just the most recent examples.

In one National Institute on Drug Abuse-funded study,
researchers from the University of Pittsburgh tracked
the drug use patterns of 224 boys, starting at age 10
to 12 and ending at age 22. Right from the beginning
these kids confounded expectations. Some followed the
traditional gateway paradigm, starting with tobacco or
alcohol and moving on to marijuana, but some reversed
the pattern, starting with marijuana first. And some
never progressed from one substance to another at all.

When they looked at the detailed data on these kids,
the researchers found that the gateway theory simply
didn't hold; environmental factors such as
neighborhood characteristics played a much larger role
than which drug the boys happened to use first.
"Abusable drugs," they wrote, "occupy neither a
specific place in a hierarchy nor a discrete position
in a temporal sequence."

Lead researcher Dr. Ralph E. Tarter told the
Pittsburgh Post-Gazette, "It runs counter to about six
decades of current drug policy in the country, where
we believe that if we can't stop kids from using
marijuana, then they're going to go on and become
addicts to hard drugs."

Researchers in Brisbane, Australia, and St. Louis
reached much the same conclusion in a larger and more
complex study published last month. The research
involved more than 4,000 Australian twins whose use of
marijuana and other drugs was followed in detail from
adolescence into adulthood.

Then -- and here's the fascinating part -- they
matched the real-world data from the twins to
mathematical models based on 13 different explanations
of how use of marijuana and other illicit drugs might
be related. These models ranged from pure chance --
assuming that any overlap between use of marijuana and
other drugs is random -- to models in which underlying
genetic or environmental factors lead to both
marijuana and other drug use or models in which
marijuana use causes use of other drugs or vice versa.

When they crunched the numbers, only one conclusion
made sense: "Cannabis and other illicit drug use and
misuse co-occur in the population due to common risk
factors (correlated vulnerabilities) or a liability
that is in part shared." Translated to plain English:
the data don't show that marijuana causes use of other
drugs, but instead indicate that the same factors that
make people likely to try marijuana also make them
likely to try other substances.

In the final blow to claims that marijuana must remain
illegal to keep us from becoming a nation of hard-drug
addicts, the researchers added that any gateway effect
that does exist is "more likely to be social than
pharmacological," occurring because marijuana
"introduces users to a provider (peer or black
marketer) who eventually becomes the source for other
illicit drugs." In other words, the gateway isn't
marijuana; it's laws that put marijuana into the same
criminal underground with speed and heroin.

The lie that marijuana somehow turns people into
junkies is dead. Officials who insist on repeating it
as a way of squelching discussion about common-sense
reforms should be laughed off the stage.

Bruce Mirken is communications director for the
Marijuana Policy Project.

By Bruce Mirken, Marijuana Policy Project
Posted on December 19, 2006

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