A central idea of the war on drugs has always been that loosening restrictions on drug use — by decriminalizing it, or allowing medical use, or legalizing some drugs completely, or even simply discussing legalization — will "send the wrong message" to kids and lead to increased teen drug use and all the problems associated therewith.
But particularly in the realm of marijuana policy, the evidence has repeatedly shown this notion to be inaccurate. After all, 20 states have passed decriminalization measures. And since 1996, 34 states have passed some sort of medical marijuana bill. But, according to two new studies published in the past month, teen use of marijuana has fallen over that same period.
"Despite considerable changes in state marijuana policies over the past 15 years, marijuana use among high school students has largely declined," concludes one of the papers, published in Drug and Alcohol Dependence. The study looks at marijuana use among all high school students in the United States, as measured every two years by the National Youth Risk Behavior Survey. In 1999, 47.2 percent of high schoolers had reported ever using marijuana in their lifetime. That number plummeted to 36.8 percent in 2009. It crept back up to 40.7 percent by 2013, but the study's authors found that that uptick is, so far, not statistically significant.
The study found similar patterns held true when you look at monthly use and daily use. Now, the researchers do say that the small uptick since 2009 is worth keeping an eye on.
"It is unclear whether observed increases in annual lifetime marijuana use since 2009 are atypical observations, or early indicators that the decline in use has reversed course." They conclude that "although our results do not suggest that the rapid pace of change to state-level marijuana policies has resulted in immediate and drastic increases in adolescent use, continued monitoring is necessary to observe how trends change over a longer period of time."
The other study, published in the American Journal of Drug and Alcohol Abuse, suggests one reason behind the downward trend in use: strong disapproval of marijuana use among younger teens is up sharply from where it was even 10 years ago.
That study looked at a different set of data -- attitudes toward marijuana and use of the drug as reported in the National Survey on Drug Use and Health. These numbers also show a decrease in marijuana use rates, in the window from 2002 to 2013. Disapproval is up sharply among teens age 13 and 14, and roughly flat among older teens.
The change in attitudes among the younger group is significant, as kids who start smoking weed at a young age are more likely to experience negative health and schooling impacts from it later on. But, "perceptions and practices of younger adolescents with respect to marijuana have not been negatively impacted by recent marijuana-related changes in public policy and perception," the study found. "In fact, we observed significant increases in disapproval and decreases in both past year and lifetime marijuana use among this important developmental subgroup."
Again, these data only go through 2013. So it's highly premature to draw any sweeping conclusions about the impact of marijuana legalization in Colorado and Washington on teen use. But, taken as a whole these two studies add to the body of evidence that shows that rapid changes in state laws and evolution in public opinion on marijuana over the past 15 or so years haven't led to the explosion in teen pot addicts that many proponents of the war on drugs feared.
Aside from growing disapproval among the younger cohort, the first of the two studies outlines some reasons why use rates have remained flat or declining among teens. Crucially, marijuana has always been easy for teens to get ahold of. Since the 1970s, the proportion of 12th-graders who say that marijuana would be "easy" to get has remained well over 80 percent. Tenth and 12th graders generally say that marijuana is only a little harder to get their hands on than alcohol.
So if teens aren't smoking pot, it's largely by choice -- not because it's unavailable to them. And that may be a reassuring fact as more states decide whether to legalize the drug.