But the researchers and public officials who crunch those numbers warned that some of the statistics gleaned from an annual survey of 46,000 American eighth-, 10th- and 12th-graders are worrisome. Although drug and alcohol use seems to be declining or holding steady, there has been slippage in teen disapproval of such practices and perception of the risks, officials warned. Take marijuana use, which has declined steadily among teens since the mid-1990s. This year, 19.4 percent of high school seniors said they had smoked marijuana at some point in the prior 30 days, as did 13.8 percent of 10th-graders and 11.8 percent of eighth-graders. But decline in pot use has stalled in the past five years, and kids' attitudes suggest a reversal may be ahead. In 1991, 58 percent of eighth-graders said they thought occasional marijuana use is harmful. By last year, that number had fallen to 48 percent and this year to 45 percent. In a news conference Monday, Gil Kerlikowske, the Obama administration's drug czar, called such numbers 'a warning sign.' 'When beliefs soften, drug use worsens,' said Kerlikowske, whose office is expected to release its first policy initiatives to combat and treat drug abuse in February. University of Michigan researcher Lloyd Johnston, who oversees the survey, said there was 'serious softening' in the risks kids perceived in use of the party drug Ecstasy, LSD and inhalants -- a sign that 'a new generation of kids are interested ... in rediscovering these drugs, because they don't understand why they shouldn't be using them.' Johnston also flagged a phenomenon the survey has begun to track -- 'extreme binge drinking,' or the consumption of more than 10 drinks on a single occasion. The survey's findings suggest that such high-risk drinking is not unusual among older teens. Binge drinking, defined as consumption of five drinks or more at a time, has declined since peaking in 1983. But Johnston said there has been 'not much decline' in numbers of extreme binge drinkers. Among high school seniors, 11 percent said they had drunk 10 drinks or more in a row in the two weeks before the survey; 6 percent said they had had 15 or more. The survey also showed that U.S. adolescents continue to raid their parents' and friends' medicine chests for drugs of abuse. Use of prescription painkillers is at an all-time high: Ten percent of high-school seniors reported taking Vicodin for nonmedical reasons in the last year and 5 percent Oxycontin. Dr. Nora Volkow, director of the National Institute on Drug Abuse, which has commissioned the survey for 35 years, said at the news conference that teen use of prescription stimulant drugs is holding steady, with just more than 7 percent of 10th- and 12th-graders reporting they had taken amphetamines -- drugs prescribed to many children as treatment for attention-deficit hyperactivity disorder -- for nonmedical reasons. Volkow said that in many cases, teens take these drugs before tests or study sessions as 'cognitive enhancers.' 