The limited relevance of drug policy: cannabis in Amsterdam and in San Francisco.

OBJECTIVES We tested the premise that punishment for cannabis use deters use and thereby benefits public health. METHODS We compared representative samples of experienced cannabis users in similar cities with opposing cannabis policies-Amsterdam, the Netherlands (decriminalization), and San Francisco, Calif (criminalization). We 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. RESULTS With the exception of higher drug use in San Francisco, we found strong similarities across both cities. We found no evidence to support claims that criminalization reduces use or that decriminalization increases use. CONCLUSIONS Drug policies may have less impact on cannabis use than is currently thought.