Marijuana Use Down in American High-Schoolers

American high school students are using marijuana at a significantly lower rate than they were 15 years ago, according to a new study. This reduction is in spite of marijuana being more widely available as several states have legalized its use for medical purposes or decriminalized it.

However, marijuana use among teens is significantly greater than the use of other illegal drugs, with 40% of teens in 2013 saying they had ever smoked marijuana. In 2009, that number was 37%, but it is still better than the 47% recorded in 1999. By contrast, only 3% of teens said they had ever tried methamphetamines in 2013, down from 9% in 1999.

The study also found that the gender gap in marijuana use, where boys outnumbered girls as users of the drug, is shrinking. Males and females are now using marijuana at similar rates. White and black teens once used marijuana at similar rates, but now blacks report using it more often.

These findings were published in the journal Drug and Alcohol Dependence. The study was conducted by researchers at the Johns Hopkins Bloomberg School of Public Health led by Renee M. Johnson, PhD, MPH, an assistant professor in the Department of Mental Health.

Johnson and her colleagues examined data from the National Youth Risk Behavior Survey, a school-based survey of students in grades 9 through 12. The survey gathered information from more than 115,000 teens throughout the United States and has been conducted every 2 years since 1990by the U.S. Centers for Disease Control and Prevention.

Since 1996, 34 states have passed laws lifting criminal sanctions of medical use of marijuana. Eleven states have passed laws decriminalizing possession of small amounts of marijuana, adding to nine that passed such laws in the late 1970s. Four states have passed laws allowing for recreational use of marijuana by people over 21.

 "People have been very quick to say that marijuana use is going up and up and up in this country, particularly now that marijuana has become more normalized," says Dr. Johnson in a statement. "What we are seeing is that since 1999 - 3 years after medical marijuana was first approved - the rates of marijuana use have actually fallen. But we will be watching those states where recreational marijuana use has been legalized to see if that leads to increased use among teens."