Marijuana use is down among teens, according to a new study by the National Institutes on Drug Abuse and the University of Michigan.
The study, titled “Monitoring the Future,” is a yearly survey of drug use among eighth, 10th, and 12th graders.
Researchers found that there has been a drop of two percentage points in the number of teens who report using marijuana in the last year, a change from the last five years when use increased.
The use of marijuana also decreased from previous years in each category of students. The study found that 15.6 percent of eighth graders report using marijuana in their lifetimes, as well as 33.7 percent of 10th graders, and 44.4 percent of 12th graders. In the past month, 6.5 percent of eighth graders, 16.6 percent of 10th graders and 21.2 percent of 12th graders admitted to marijuana use.
According to the authors of the study, “personal disapproval” of the use of pot also fell among students in the eighth and 12th grades. “Reported availability” of the drug is “down significantly” in the eighth and 10th grades, which the authors speculate “may help to explain the modest decline in use this year.”
The number of teens who use pot on a daily basis fell, with 5.8 percent of seniors reporting daily use, compared to 6.5 percent in 2013. The researchers defined daily or near-daily marijuana use as “use on 20 or more occasions in the prior 30 days.”
Conversely, the authors of the study found that “the belief that regular marijuana use harms the user, however, continues to fall among youth, so changes in this belief do not seem to explain the change in use this year, as it has done over most of the life of the study.”
The study of 40,000 teens indicates that their use of other harmful substances – such as alcohol and cigarettes – also has decreased. Less than 15 percent of high school seniors reported smoking cigarettes in the last month, and less than 40 percent report drinking alcohol.
The Washington Post notes that the study was conducted this spring, as several states and the District of Columbia debated legalizing marijuana.