Do Medical Marijuana Laws Increase Adolescent Marijuana Abuse?

This year, Illinois and New Hampshire will join 18 other states and the District of Columbia in allowing the sale and possession of marijuana for medical use. Across the country, states are taking steps to relax the prohibition of marijuana, most notably in Colorado and Washington where voters have legalized it for recreational use. Nevertheless, handwringing continues about the possible unintended consequences of these policies, particularly on young people. Critics, concerned with marijuana’s effect on adolescents, say that medical marijuana laws (MMLs) will mean adolescents need only raid the medicine cabinet or pantry to get ahold of marijuana. Proponents of MMLs counter that if children are going to abuse prescription drugs, the side effects of marijuana abuse are relatively minor compared to oxycodone or hydrocodone (Vicodin). Additionally, while medical marijuana requires a doctor’s recommendation and recreational marijuana requires proof of age, those who control the illicit drug market are not so discriminating.

On January 15^th of this year, the New Hampshire House of Representatives became the first state legislative chamber to pass a bill that would legalize marijuana for recreational use. Even so, Governor Maggie Hassan, a Democrat, promised to veto the bill, effectively killing it. When asked about the reason for her opposition, Governor Hassan responded, “I just think it’s the wrong message to send to young people.”

So does expanded access to legal marijuana increase its use among adolescents? Sarah Lynne-Landsman, Melvin Livingston, and Alexander Wagenaar of the University of Florida are skeptical. Their study, “Effects of State Medical Marijuana Laws on Adolescent Marijuana Use,” published in the American Journal of Public Health, suggests, “MMLs have not measurably affected adolescent marijuana use in the first few years after their enactment.”

Lynne-Landsman, Livingston, and Wagenaar used data from the Youth Risk Behavior Survey to perform a difference-in-difference analysis of MMLs. Montana, Rhode Island, Michigan, and Delaware all passed varying types of MMLs at different points from 2003 to 2011, allowing the authors to control for national trends in addition to explicitly controlling for age, ethnicity, and gender. After running 40 comparisons of adolescents in these states over this eight-year period, in only two instances did MMLs have a statistically significant impact on abuse rates, an outcome that can be attributed to error when defining significance as a p-value less than 0.05. In every other comparison, MMLs had no significant effect on adolescent past-month or lifetime marijuana use.

While there may still be legitimate concerns over the effects of expanding access to legal marijuana, this study suggests that increased adolescent use is not one of them. The authors acknowledge that their study has a number of shortcomings, including not being able to control for differences between state MMLs with respect to things like qualifying ailments, license fees, possession limits, and growing limits. They also recommend that future studies examine this issue using different measures of marijuana use and different states. In addition, given the number of states moving toward full legalization, the time may soon be right to examine the effects of those laws on adolescent use, as medical marijuana laws may not be a perfect corollary. Nevertheless, this study provides strong evidence that the concerns over increased youth marijuana abuse are potentially misplaced.

Article Source: Sarah Lynne-Landsman, Melvin Livingston, and Alexander Wagenaar, “Effects of State Medical Marijuana Laws on Adolescent Marijuana Use,” American Journal of Public Health 103, No. 8 (Aug 2013): 1500-6.

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