Teen Marijuana Use Down Despite Greater Availability.
Marijuana use among American high school students is significantly lower today than it was 15 years ago, despite the legalization in many states of marijuana for medical purposes, a move toward decriminalization of the drug, and the approval of its recreational use in a handful of places, a new study co-authored by School of Public Health researchers suggests.
However, the study also found that marijuana use is significantly greater than the use of other illegal drugs, with 40 percent of teens in 2013 saying they had ever smoked marijuana. That number was down from 47 percent in 1999 but up from 37 percent in 2009. By contrast, just 3 percent had ever tried methamphetamines in 2013 as compared to 9 percent in 1999.
The findings, published online in the journal Drug and Alcohol Dependence and led by Renee M. Johnson of the Johns Hopkins Bloomberg School of Public Health, also suggest that a gender gap in marijuana use—where boys outnumbered girls as users of the drug—is shrinking, with males and females now using marijuana at similar rates. And while white and black teens used to use marijuana at similar rates, now blacks report using the drug more often.
SPH researchers on the study are Emily Rothman, associate professor of community health sciences, and Ziming Xuan, assistant professor of community health sciences.
Marijuana policy has undergone significant changes over the past 20 years. Since 1996, 34 states have passed legislation removing criminal sanctions for 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 the recreational use of marijuana for people over 21.
The research team examined data from the National Youth Risk Behavior Survey, a biennial school-based survey of students in grades 9 through 12, which gathered information from more 115,000 adolescents throughout the US. They analyzed information from 1999 to 2013. The survey has been conducted by the US Centers for Disease Control and Prevention since 1990.
Use of other illegal drugs including hallucinogens and cocaine has also fallen throughout the time period, as has use of alcohol and cigarettes among teens. In 2013, 41.1 percent of the teens surveyed said they had smoked cigarettes in their lifetime, while 40.7 percent said they had used marijuana in their lifetime. The rates of cigarette smoking are down from 70.4 percent in 1999. Those who said they had ever tried alcohol fell from 81 percent in 1999 to 66.2 percent in 2013.
In 1999, the survey found, 51 percent of girls and 43 percent of girls had ever used marijuana, and by 2013, 42 percent of boys and 39 of girls say they had used it in their lifetimes. In 1999, 29 percent of both white and black teens reported having used marijuana; in 2013, 29 percent of black and 20 percent of white teens had used the drug.
The study was funded by grants from the National Institutes of Health’s National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism.