The Netherlands and Depenalization of Cannabis Use
"There is no evidence that the depenalization component of the 1976 policy, per se, increased levels of cannabis use. On the other hand, the later growth in commercial access to cannabis, after de facto legalization, was accompanied by steep increases in use, even among youth. In interpreting that association, three points deserve emphasis. First, the association may not be causal; we have already seen that recent increases occurred in the United States and Oslo despite very different policies. Second, throughout most of the first two decades of the 1976 policy, Dutch use levels have remained at or below those in the United States. And third, it remains to be seen whether prevalence levels will drop again in response to the reduction to a 5-g limit, and to recent government efforts to close down coffee shops and more aggressively enforce the regulations."
MacCoun, Robert and Reuter, Peter, "Interpreting Dutch Cannabis Policy: Reasoning by Analogy in the Legalization Debate," Science (New York, NY: American Association for the Advancement of Science, October 3, 1997), pp. 50-51.