Marijuana use among teenagers increased this year after previous declines, while the use of other illicit drugs like cocaine mostly declined.
According to an annual National Institute on Drug Abuse-funded survey of nearly 47,000 students, almost one-third of 12th-graders and more than one-quarter of 10th-graders reported using marijuana in 2009. Almost 12% of eighth-graders reported marijuana use, an increase from about 11% in 2008.
The survey, conducted by researchers at the University of Michigan, asked teenagers to report on the use of smoking, alcohol use and drug use, including non-medical uses of prescription painkillers and over-the-counter cold and cough products.
The report showed cigarette smoking was at the lowest point since the survey started in 1975, although the use of smokeless-tobacco products increased on some measures this year.