Marijuana use among American high school students is significantly lower today than 15 years ago—even though many states have legalized medical marijuana, moved toward decriminalization, and approved of recreational use in a handful of places.
Marijuana use, however, is still significantly greater than the use of other illegal drugs, the study also finds. The researchers say 40 percent of teens in 2013 said they had smoked marijuana at least once, 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 with 9 percent in 1999.
The findings, published online in the journal Drug and Alcohol Dependence, also suggest the gender gap in marijuana use—boys outnumbering girls as users of the drug—is shrinking; males and females now use marijuana at similar rates.
While white and black teens once used marijuana at similar rates, now blacks report using the drug more often.
Marijuana policy has undergone significant changes over the past 20 years. Since 1996, 34 states have repealed criminal sanctions for medical use of marijuana. Eleven have decriminalized possession of small amounts, adding to nine that passed such laws in the late 1970s. Four states have passed laws allowing for the recreational use 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 study leader Renee M. Johnson, assistant professor of mental health at the Johns Hopkins Bloomberg School of Public Health.
“What we are seeing is that since 1999—three 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.”
Colorado, Oregon, Alaska, Washington, and the District of Columbia have only recently legalized some recreational use of marijuana. The longer those laws are in place, Johnson says, the more likely there could be an effect on marijuana use among teens—even though it is still illegal to use pot under age 21 under state law, and federal law continues to prohibit all use.
Johnson and her colleagues 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 than 115,000 adolescents throughout the United States. They analyzed information from 1999 to 2013. The survey has been conducted by the US Centers for Disease Control and Prevention since 1990.
The survey found that in 1999, 51 percent of boys and 43 percent of girls had ever used marijuana, and by 2013, 42 percent of boys and 39 percent 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 teens and 20 percent of white teens had used the drug.
Even though marijuana use is lower than 15 years ago, Johnson says it may be time again to promote programs that educate high school students about the specific harms of marijuana use. The recent focus has been more on preventing teens from using tobacco and alcohol.
“We’ve done a really good job in public health of alcohol and tobacco use prevention,” she says. “We haven’t done the same with marijuana. We would do well to follow the lessons learned from those programs, which have been pretty successful.”
The National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism supported the work.
Source: Johns Hopkins University