PERSPECTIVES: MARIJUANA MYTH GETS BUSTED

It's Now Clear That Pot Doesn't Lead to Hard-Core Drug Use

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 hard drugs,
often called the "gateway theory."

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 Mr. 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 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 ages 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 marketeer) 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.