In an essay recently published online by the journal Addiction, U.C.-Berkeley psychologist Robert J. MacCoun, a leading drug policy scholar, reviews the evidence concerning the impact of quasi-legalization on marijuana consumption in the Netherlands. Since 1976 the Dutch government has tolerated the retail sale of cannabis (which is still officially prohibited) while continuing to enforce bans on production and large-scale distribution. Although this policy had "no detectable effects on cannabis use" for a dozen years, MacCoun writes, from 1984 to 1996 "the percentage of 18–20-year-olds who had ever used cannabis rose from 15% to 44%, with past-month prevalence rising from 8.5% to 18.5%." He argues that the "the rapid expansion of retail cannabis outlets" during this period helps explain the rise in consumption, which occurred at a time when "prevalence trends were either flat or declining in the United States, Oslo, Catalunya, Stockholm, Denmark, Germany, Canada and Australia." Marijuana use nevertheless remained less common in the Netherlands, where it was openly sold in safe and friendly cafés, than in the United States, where it had to be purchased and consumed surreptitiously at the risk of arrest. "Cannabis consumption in the Netherlands is lower than would be expected in an unrestricted market," MacCoun says, "perhaps because cannabis prices have remained high due to production-level prohibitions." His major findings:

The available evidence suggests that the prevalence of cannabis use among Dutch citizens rose and fell as the number of coffeeshops increased and later declined, but only modestly. The coffeeshops do not appear to encourage escalation into heavier use or lengthier using careers, although treatment rates for cannabis are higher than elsewhere in Europe [but lower than in the U.S.]. Scatterplot analyses suggest that Dutch patterns of use are very typical for Europe, and that the "separation of markets" may indeed have somewhat weakened the link between cannabis use and the use of cocaine or amphetamines.

MacCoun notes that the relatively high treatment rate in the Netherlands (compared to the rates of most other European countries) seems inconsistent with Dutch users' "relatively modest cannabis continuation rates" and "quantities consumed." He says "one possibility is that the Dutch are more generous and proactive in providing treatment."

MacCoun cautions that the Dutch policy is not really legalization, so it does not necessarily tell us what might happen if all penalties for production and sale were eliminated. But it is striking that the worst consequence of allowing cannabis cafés he cites—the increase in casual use among young adults between 1984 and 1996—is alarming only if you assume that it caused serious personal or social problems. MacCoun says "other types of consequences (for public safety, public order, economic productivity, family life, health and personal enjoyment) are not examined because they are so difficult to quantify and because they pose such severe causal identification problems." But in the absence of some evidence than an increase in marijuana consumption causes intolerable difficulties, it should be counted as a benefit, not a cost, since people smoke pot because they enjoy it, and more pleasure, other things being equal, is a good thing.

In his May 2010 Reason cover story about "L.A.'s Pot Revolution," Brian Doherty argued that the fallout from open, widespread retail sale of cannabis in Los Angeles was similarly unalarming. A few months ago, I noted that Holland's highest court had blessed the Dutch government's new policy of closing "coffeehouses" to foreigners, which is officially motivated by the nuisances associated with "drug tourism." MacCoun says the shift is partly due to "the complexities of recent coalition politics" in the Netherlands—"in particular the rising influence of Geert Wilders' far-right party."

Remember when Bill Clinton's drug czar, in his eagerness to demonstrate the folly of the Dutch model, claimed "the murder rate in Holland is double that in the United States"? 

[Thanks to Allen St. Pierre for the tip.]