With the U.S. Drug Enforcement Administration celebrating its 35th birthday this week, the publication of a new study estimating drug use rates across countries is well-timed. Of the 17 countries surveyed by the World Health Organization, China has the lowest rate of illegal drug use (cannabis and cocaine combined), followed by Japan, while the United States has the highest rate, followed closely by New Zealand. (Here is a comparison table.) "Globally," the researchers report, "drug use is not distributed evenly and is not simply related to drug policy, since countries with stringent user-level illegal drug policies did not have lower levels of use than countries with liberal ones." It may be that the United States has especially stringent drug policies partly because it has especially high levels of drug use. But it seems clear, after you look at drug use not only across countries but over time in the U.S., that the ebbs and flows have little to do with the intensity of drug law enforcement (which is not to say that prohibition itself has no impact).
As I mentioned yesterday, changes in drug use among teenagers since the DEA was established in the 1970s are not very impressive. I focused on drug use by high school seniors because it is a measure of success commonly used by drug warriors and because the government has comparable data for that group going back more than three decades. But whichever age group you look at, trends in drug use do not correspond very well with changes in drug control efforts. Overall, drug use in the U.S. peaked around 1979 and began to fall well before Ronald Reagan ramped up the war on drugs. As Republicans are fond of noting, drug use did rise during the Clinton administration, but it started to fall again before anything George W. Bush did differently could have had an impact. Although marijuana arrests have increased by more than 150 percent since 1990, marijuana use seems to be just as common today as it was then, if not more so. There is some uncertainty on that point, since the government changed the techniques used in its broadest drug use survey during this period. But in the Monitoring the Future Study, the rate for past-year marijuana use among high school seniors was 31.7 percent percent in 2007, compared to 32.5 percent in 1990.
Getting back to the WHO study, it's striking that the lifetime marijuana use rate in the U.S. (42.4 percent) is more than twice as high as the rate in the Netherlands (19.8 percent), despite the latter country's famously (or notoriously, depending on your perspective) tolerant cannabis policies. The difference for lifetime cocaine use is even bigger: The U.S. rate (16.2 percent) is eight times the Dutch rate (1.9 percet). Do these results mean that draconian drug laws promote drug use, while a relatively laid-back approach discourages it? Not necessarily; that would be a hell of a "forbidden fruit" effect. But one thing that's clear is the point made by the WHO researchers: Drug use "is not simply related to drug policy." If tinkering with drug policy (within the context of prohibition) has an impact, it is hard to discern, and it's small compared to the influence of culture and economics.