Ever since activists began campaigning for ballot initiatives that recognize cannabis as a medicine, the Marijuana Policy Project notes in a new report, drug warriors have been warning that such measures "send the wrong message to young people," as DEA Administrator Thomas Constantine put it just before California voters approved the nation's first medical marijuana law in 1996. Constantine elaborated:
How can we expect our children to reject drugs when some authorities are telling them that illegal drugs should no longer remain illegal, but should be used instead to help the sick?…We cannot afford to send ambivalent messages about drugs.
Connecticut Gov. M. Jodi Rell cited the same concern when she vetoed a medical marijuana bill in 2007, and last year drug czar Gil Kerlikowske told the Associated Press, "I think all of the attention and the focus of calling marijuana medicine has sent the absolute wrong message to our young people." This argument has never made much sense to me, since it seems implausible that linking marijuana to cancer and AIDS patients would make it seem cooler to teenagers. The government permits medical use of many drugs that can be used to get high. Does giving morphine to cancer patients or Adderall to narcoleptics "send the wrong message to young people"?
In any case, as the MPP report shows, there is very little evidence that medical marijuana laws encourage teenagers to smoke pot. Karen O'Keefe, MPP's director of state policies, and Mitch Earleywine, a marijuana expert who is a psychology professor at SUNY-Albany, looked at all the available survey data on pot consumption by teenagers before and after the legalization of medical marijuana. Here is what they found:
Nearly 15 years after the passage of the nation's first state medical marijuana law, California's Prop. 215, a considerable body of data shows that teens' marijuana use has generally gone down following the passage of medical marijuana laws. Of the 13 states with effective medical marijuana laws with before-and-after data on teen marijuana use, only the two with the most recently enacted laws (Michigan and New Mexico) have indicated possible increases, both of which are modest and [statistically insignificant]. In Rhode Island, the data indicate teens' lifetime marijuana may have slightly decreased while current use may have slightly increased, but those changes are also within confidence intervals. The 10 remaining states have all reported overall decreases—some of which are also [statistically insignificant] and some of which are significant. Generally, no state with an overall change outside of the confidence intervals saw an increase in teens' marijuana use, strongly suggesting that enactment of state medical marijuana laws does not increase teen marijuana use.
Marijuana use declined nationwide during this period, and it does not look like that downward trend was weaker in states with medical marijuana laws. In the Youth Risk Behavior Surveillance System's national surveys (conducted every two years), the share of ninth-graders reporting past-month marijuana use fell from 20.9 percent in 1995 to 15.5 percent in 2009, a drop of 26 percent. In the California Student Survey, that rate fell from from 23.6 in 1995 (the year before Prop. 215 was approved) to 15.4 percent in 2008, a drop of 35 percent.