The Netherlandss system of quasi-legal retail marijuana sales  steadily evolving since 1976  may have modestly increased the number of marijuana users, but does not seem to have intensified their use of marijuana or the likelihood that they will move on to harder drugs, according to a University of California, Berkeley, study just published in the journal Addiction.

In the article, Robert J. MacCoun, a professor at UC Berkeleys Goldman School of Public Policy and the UC Berkeley School of Law, said that the well-documented Dutch experience with marijuana shops may provide important information for other jurisdictions wrestling with how to deal with cannabis.

Several factors, including a ban on advertising and prohibitions on marijuana cultivation that keep prices relatively high, likely moderate the use of marijuana in the Netherlands relative to what one might see in a completely legalized regime, said MacCoun. At the same time, the Dutch seem to have reduced contact between marijuana users and hard drug users and sellers by separating the markets for each via the cannabis coffee shop system, he added.

In addition, MacCoun found that:

 Dutch citizens use cannabis at more modest rates than many of their European neighbors.

 Dutch youth report high rates of availability of cannabis, but not as elevated as reported rates in the United States and several other countries.

 The Dutch continuation rate for using marijuana from a causal experimentation in youth to regular usage in adulthood (ages 15-34) is fairly modest by international standards

 Past-year cannabis use among Dutch 15-to-24-year-olds dropped from 14.3 to 11.4 percent between 1997 and 2005.

 Dutch cannabis users are more likely to be admitted for substance abuse treatment than their counterparts in most European countries, while the United States reports four marijuana treatment admissions for every one admission in the Netherlands. It is not clear whether this reflects a greater investment in treatment by Dutch officials, or the higher potency of Dutch marijuana.

 In the United States, about half of those admitted for treatment for marijuana addiction happen through criminal justice referrals. In the Netherlands, such referrals account for closer to 10 percent.

In the journal, MacCoun noted some interesting details about the Dutch system, how it is regulated, who it attracts and how it is changing.

For example, there are about 700 retail marijuana outlets  one for every 29,000 Dutch citizens  although the concentration in the city of Amsterdam is closer to one for every 3,000 people. The Netherlands sells about 50 to 150 metric tons of cannabis annually in its licensed shops, and in 1995 reduced the maximum individual purchase from 30 grams to five.

As for Dutch youth, MacCoun said they resemble American youth in that they are likely to start using marijuana before they turn 13, even though the age limit for legal purchases in the Netherlands was 16 until 2005, when it was increased to age 18.

The international traveler is a big part of the Dutch cannabis system, said MacCoun, with an estimated quarter of the 4 to 5 million tourists who visit Amsterdam every year stopping by a local marijuana shop. However, the Dutch have recently announced a plan to run the cannabis coffee shops as private clubs for the Dutch only, excluding foreign visitors. MacCoun said this is probably due as much to the rising influence of the conservatives within Dutch coalition politics who are concerned about drug tourism or nuisance reports.

That change, in turn, is likely to further reduce the number of cannabis shops, which already has dropped from an all-time high of 1,179 to just over 700 today, he said.

For his study, MacCoun compared available data on the prevalence and patterns in the Netherlands of marijuana use, treatment for marijuana addiction, and the sanctioning and prices for marijuana, with similar data for Europe and the United States.

The paper is the latest in his ongoing examination of drug use and public policy in the United States and elsewhere. In the book, Drug War Heresies (2001), co-authored with Peter Reuter of the University of Maryland, College Park, MacCoun called for a more nuanced approach to societal struggles with drug use, rather than simply zero tolerance or blanket legalization.

There are daunting analytical challenges in making cross-national comparisons of drug policies and outcomes, MacCoun wrote in the journal Addiction, but if we want to identify more effective policies, we need to make comparisons across jurisdictions, and it is surely better to make provisional judgments than provincial ones.

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More information: A news release about an earlier study on the Dutch cannabis system by MacCoun is A news release about an earlier study on the Dutch cannabis system by MacCoun is online