Image: KL after Marijuana and Youth

When the price or perceived risk of marijuana rises, teens really don't inhale, according to a new study from researchers at the University of Illinois at Chicago and the University of Michigan. "This is the first paper that uses nationally representative data to look at the impact of price on youth marijuana use," says Frank Chaloupka, a professor of economics at UIC and director of the UIC ImpacTeen Project. The complete findings, Marijuana and Youth, are presented in a paper from Bridging the Gap, an initiative that pairs ImpacTeen with the University of Michigan's Youth Education and Society Project (YES).

To chart these trends, the paper's authors used data on marijuana prices and potency from the U.S. Drug Enforcement Administration's Office of Intelligence. For numbers on the drug's demand, they turned to the University of Michigan's annual Monitoring of the Future Survey, which is conducted among a nationally representative sample of American high school seniors. In all, they found that use fell to an all-time low between 1981 and 1992, a period in which the price of marijuana tripled, only to rise again after 1992 when the price dropped 16 percent. So, too, between 1981 and 1992, fears of the drug's harmful effects increased and then died down in the early 90s.

Earlier studies looking at trends in marijuana's popularity have taken its price into account, but they have typically relied on small, unrepresentative samples. Now the effects of price should receive greater attention. "Changes in the price of marijuana and in the perceived risk of harm from regular marijuana use contribute to an understanding of the number of teens who use marijuana," Chaloupka comments, "and underscore the usefulness of considering price in addition to more traditional determinants in future studies."