Sixteen percent of eighth-graders say they’ve used marijuana in the past year — up from 14.5 percent in 2009, according to the “Monitoring the Future” survey, an annual study of substance use among a nationally representative sample of 42,000 eighth-, 10th- and 12th-graders sponsored by the National Institute on Drug Abuse. This trend, in combination with a similar uptick in marijuana use among high school students, should be a major cause of concern for parents and educators, says NIDA Director Nora D. Volkow, MD.

“We know that the younger the age of initiation, the greater likelihood they will become dependent,” she says. According to Volkow, the rise may be the result of marijuana legalization efforts. But while such campaigns tout the medicinal effects of marijuana for chronic pain sufferers, “we know unequivocally that marijuana affects learning and memory,” she says. “It’s a loss for adolescents exposed to this, and a loss for all of us.”

The survey’s results weren’t all bad. Binge drinking is declining, with 23.2 percent of high school seniors saying they’d had five or more alcoholic drinks in a row over the last two weeks, as compared to 25.2 percent in 2009 and 31.5 percent in 1998.

—S. Dingfelder

Past year marijuana use among teens