May 3, 2004
Dutch drug policies do not increase marijuana
use, first rigorous comparative study finds
By Jennifer McNulty
In the first rigorous study comparing marijuana use in the Netherlands
and the United States, researchers have found no evidence that decriminalization
of marijuana leads to increased drug use. The results suggest that drug
policies may have less impact on marijuana use than is currently thought.
In Amsterdam, coffeeshops can be licensed to sell hashish and
marijuana in small quantities for personal consumption by adults.
Photo by Janice Tetlow
The findings appear in the May issue of the American Journal of
Public Health. Craig Reinarman, professor of sociology at UCSC,
coauthored the article, The Limited Relevance of Drug Policy:
Cannabis in Amsterdam and in San Francisco, with Peter D. A. Cohen,
director of the Centre for Drug Research (CEDRO) at the University of
Amsterdam in the Netherlands, and Hendrien L. Kaal, now an instructor
at the University of Leiden in the Netherlands.
The study compared the cannabis (marijuana and hashish) habits of users
in Amsterdam and San Francisco to test the premise that punishment for
cannabis use deters use and thereby benefits public health.
We compared representative samples of experienced marijuana users
to see whether the lawful availability of marijuana did, in fact, lead
to the problems critics of the Dutch system have claimed, said
Reinarman. We found no evidence that it does. In fact, we found
consistently strong similarities in patterns of marijuana use, despite
vastly different national drug policies.
Highlights of the study include:
The mean age at onset of use was 16.95 years in Amsterdam and
16.43 years in San Francisco.
The mean age at which respondents began using marijuana more
than once per month was 19.11 years in Amsterdam and 18.81 years in
In both cities, users began their periods of maximum use about
two years after they began regular use: 21.46 years in Amsterdam and
21.98 years in San Francisco.
About 75 percent in both cities had used cannabis less than
once per week or not at all in the year before the interview.
Majorities of experienced users in both cities never used marijuana
daily or in large amounts even during their periods of peak use, and
use declined after those peak periods.
The Netherlands effectively decriminalized marijuana use in 1976, and
it is available for purchase in small quantities by adults in licensed
coffee shops; in the United States, marijuana use carries stiff criminal
penalties, and more than 720,000 people were arrested for marijuana
offenses in 2001.
The study was funded by the U.S. National Institute on Drug Abuse (NIDA)
and the Dutch Ministry of Health.
In identical questionnaires administered in Amsterdam and San Francisco
(cities chosen for their similarities as politically liberal northern
port cities with universities and populations of roughly 700,000 people),
nearly 500 respondents who had used marijuana at least 25 times were
asked detailed questions about their marijuana use. The questionnaire
explored such issues as age at first use, regular and maximum use, frequency
and quantity of use over time, intensity and duration of intoxication,
career use patterns, and use of other illicit drugs.
In the United States, marijuana policy is based on the assertion
that strict penalties are the best way to inhibit use, said Reinarman.
The studys findings cast doubt on that scenario, he said. Despite
widespread lawful availability of cannabis in Amsterdam, there were
no differences between the two cities in age at onset of use, age at
first regular use, or age at the start of maximum use.
The study found no evidence that lawfully regulated cannabis provides
a gateway to other illicit drug use. In fact, marijuana
users in San Francisco were far more likely to have used other illicit
drugs--cocaine, crack, amphetamines, ecstasy, and opiates--than users
in Amsterdam, said Reinarman.
The results of this study shift the burden of proof now to those
who would arrest hundreds of thousands of Americans each year on the
grounds that it deters use, said Reinarman.
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