Mythbuster

New study defies government assertion that legalization increased teen marijuana use

The legalization of medical marijuana caused a big uptick in teen drug use—or at least that is what government officials like federal Drug Czar Gil Kerlikowske continue to assert. This reasoning motivates the government crackdown on dispensaries located within a 1,000 feet of a school or park.

Just don’t ask Kerlikowske & Co. to provide scientific research to support these assertions.

“I am not aware of studies by the federal government on this issue,” says Benjamin Hansen, assistant professor of economics at the University of Oregon. “Certainly federal employees have shared opinions, but I wouldn’t call that research.”

“All I can say is that [the government’s] argument—that medical marijuana is responsible for the recent increases in the use of marijuana by teenagers—is not backed up by the data,” adds Dr. Daniel Rees, professor of economics at the University of Colorado Denver. “If teen use of marijuana had gone up in the years following legalization, then we would have observed a correlation. No effect, no correlation.”

Dr. Rees, Professor Hansen and Dr. D. Mark Anderson (assistant professor of economics at Montana State University) recently coauthored the paper “Medical Marijuana Laws and Teen Marijuana Use.” The study analyzed the Youth Risky Behavior Survey (1993-2009), the National Longitudinal Survey of Youth 1997 and the Treatment Episode Data Set (TEDS) looking at related data like marijuana use and availability at school and taking other substances like cocaine and alcohol. As the paper says, “Our results are not consistent with the hypothesis that legalization leads to increased use of marijuana by teenagers.”

This might be surprising to some, but that is not the real shocker. The study actually found a net decrease in use by 15- to 17-year-olds after legalization.

“We consistently get estimates that are slightly negative [as far as usage rates],” explains Hansen. “Medical marijuana could drive down youth use for a couple reasons. First, illegal supply might go down as some drug dealers shift over to legally supply through dispensaries. Although total supply might be going up, the supply available to youth might decrease. [The sellers] now start up legal dispensaries and don’t want to risk their business by selling to someone underage without a [recommendation]. Second, more adults might be using marijuana due to the decreased punishments and the availability of medical marijuana. In previous research, we found that young adult use of medical marijuana increased by nearly 25 percent in several states for which we had data. An increase in adult demand would drive prices up, which would result in a decrease in quantity which teens demand.”

The government’s 2011 Monitoring the Future report shows an overall increase in teen marijuana use, which makes the professors’ findings even more surprising. It seems to imply that states that legalized medical marijuana were actually more effective in limiting teen use.

It is important to note that the paper itself does not argue any cause and effect, only that teen use did not increase in states that legalized medical marijuana. Federally funded studies are now in the works. In the meantime, these three professors and their pioneering study just showed that government officials are never too old to get schooled.

Just the Facts

The “Medical Marijuana Laws and Teen Marijuana Use” study isn’t the first time an academic analysis proved drug warriors’ sacred beliefs dead wrong. Last year, the Washington, D.C.-based Marijuana Policy Project released “Marijuana Use by Young People: The Impact of State Medical Marijuana Laws,” which basically concluded the same thing. In California, for instance, collected data showed a decline in the use of cannabis by 7th-, 9th- and 11th-graders between 1996 and 2009. An analysis commissioned by the California Department of Alcohol and Drug Programs found “no evidence supporting that the passage of

Proposition 215 increased marijuana use during this period.”