The Limited Relevance of Drug Policy
Cannabis in Amsterdam and in San Francisco
May 2004
Decriminalizing cannabis doesn't lead to more widespread use, according to a study comparing cannabis users in two similar cities with opposing cannabis policies — Amsterdam, the Netherlands (decriminalization), and San Francisco, California (criminalization). The study compared age at onset, regular and maximum use, frequency and quantity of use over time, intensity and duration of intoxication, career use patterns, and other drug use. No evidence was found to support claims that criminalization reduces use or that decriminalization increases use.
Download the document (PDF)
The study set out to test the premise that punishment for cannabis use deters use and thereby benefits public health. With the exception of higher drug use in San Francisco, the study found strong similarities across both cities. Drug policies may have less impact on cannabis use than is currently thought. The study found no evidence to support claims that criminalization reduces use or that decriminalization increases use. The study also 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.
The data suggest that most experienced users organize their use according to their own subcultural etiquette — norms and rules about when, where, why, with whom, and how to use — and less to laws or policies. When experienced users abide by such etiquette, they appear to regulate their cannabis use so as to minimize the risk that it will interfere with normal social functioning. This pattern suggests that if formal drug policies are based on the informal drug policies users themselves already practice, drug policies may achieve greater relevance.
The study was funded by the U.S. National Institute on Drug Abuse (NIDA) and the Dutch Ministry of Health. See the press release of the University of California.
