WASHINGTON (Reuters) - Recent declines in marijuana use by U.S. teens appear to have stalled this year and their abuse of prescription drugs remains at worrisome levels, researchers said on Thursday.
The annual survey of U.S. teen drug use, conducted by University of Michigan researchers for the U.S. government, also found continuing declines in cigarette smoking and alcohol use.
Marijuana is the most commonly used of the illicit drugs and its use had been in a slow but steady decrease this decade, but that appeared to halt this year, researchers said.
The survey found that marijuana use by students in two of the three grades measured increased slightly. The researchers said 11 percent of eighth graders, 24 percent of 10th graders, and 32 percent of 12th graders reported using the drug in the prior year.
Overall, 47 percent of 12th graders, 34 percent of 10th graders and 20 percent of eighth graders reported ever having used an illicit drug, the researchers said.
Use of any illicit drug in the prior year was reported by 37 percent of 12th graders, 27 percent of 10th graders and 14 percent of eighth graders, the researchers said. It rose in two of the three grade levels compared to the previous year.
But the annual survey has shown an overall downward trend in teen drug use this decade, and President George W. Bush, in comments at the White House, cited progress on the issue during his presidency.
"No question there's still work to do in America, but we are making progress. And one way to note the progress is this statistic -- since 2001, teen-age use has declined by 25 percent. That means 900,000 fewer teens on drugs."
Amphetamine use reached its recent peak in the 1990s but has fallen by about half since then, with 6.8 percent of 12th graders reporting having used it in the prior year, the survey found.
Abuse of Ritalin, a prescription amphetamine drug used to treat attention deficit hyperactivity disorder, has declined this decade. This year's survey found 3.4 percent of 12th graders reported having used it for non-medical purposes in the past year.
Methamphetamine, often called "meth," has been falling since its use was first tracked in the survey in 1999. Crystal methamphetamine use also declined to its lowest level since a recent peak in 2002, the researchers said.
The survey also detected declines in cocaine use, although not crack cocaine use. The results showed little change in teen use of LSD and other hallucinogens, ecstasy and heroin.
The survey showed a persistent worrisome rate of abuse of prescription medications, including the powerful painkillers Vicodin and Oxycontin, with little change in the past six years.
The findings were based on responses from 46,348 students from 386 U.S. schools.
Reporting by Will Dunham; Editing by Eric Beech