States Decriminalizing Marijuana Saw No Increase in Youth Use, Wash U Prof Finds


Do states that decriminalize marijuana see more teens using it? According to a landmark study led by a professor at Washington University, the answer is a clear no.

Dr. Richard Grucza, a professor of psychiatry at the Washington University School of Medicine, says he believes his just-published study is the first to examine the issue since one looking at California in 2015 found increased use among high school seniors, but not their counterparts in eighth grade or tenth.

But this study, published in the International Journal of Drug Policy, found no such results. And it's far more comprehensive — looking at five states (Massachusetts, Connecticut, Rhode Island, Vermont and Maryland) for a longer period of time. Massachusetts, for example, decriminalized pot in 2008; Grucza's team was able to look at seven full years of youth-use surveys, comparing them with 27 states that did not decriminalize.

And the researchers found no increase in the five states in question. Not for seniors, and not for sophomores or eighth graders either. "People have said that if the state reduces the criminal penalties for possession, that's a go-ahead for people to start using," he says. "But we have not seen dramatic increases in drug use. To say simply reclassifying it as a civil offense is sanctioning drug use is a little misguided."

The study also shows that marijuana possession arrests dropped dramatically for both children and adults — suggesting that decriminalization policies have had the intended affect.

Grucza says he hopes the study will encourage states to take a closer look at decriminalization, a step that is different from full legalization or commercialization. (In fact, it's current policy in the city of St. Louis, even though Missouri has yet to implement even a modest medical marijuana program.)

"What I hope it does it call attention to the fact that there's this other policy out there for states that are not ready for full legalization," he says.

We welcome tips and feedback. Email the author at

Support Local Journalism.
Join the Riverfront Times Press Club

Local journalism is information. Information is power. And we believe everyone deserves access to accurate independent coverage of their community and state. Our readers helped us continue this coverage in 2020, and we are so grateful for the support.

Help us keep this coverage going in 2021. Whether it's a one-time acknowledgement of this article or an ongoing membership pledge, your support goes to local-based reporting from our small but mighty team.

Join the Riverfront Times Club for as little as $5 a month.