Fewer teens drink and smoke cigarettes than in any time in the last 30 years, but the widespread availability of medical marijuana appears to be fueling a rise in pot use, health experts said Wednesday.
One in four of the 47,000 teens surveyed for the 2011 Monitoring the Future report said they had used marijuana during the last year, up from 21.4% in 2007. The survey, which polled students nationwide in the eighth, 10th and 12th grades, also found that 1 in 15 of the oldest students used pot on a daily or near-daily basis — the highest rate since 1981.
For the first time, researchers asked 12th-grade students about synthetic marijuana, which contains cannabinoids and produces a high similar to pot but is thought to be more dangerous because it can be contaminated with unknown substances. The finding — 11% of the high school seniors surveyed had tried the substance — surprised researchers.
Sold by the names Spice or K2, the drug had been widely available online and in tobacco shops until recently. In February, the Drug Enforcement Administration reclassified some of the chemicals found in the products as Schedule I controlled substances, which made them illegal.
The survey also revealed that teens don't think of marijuana as dangerous. Because of that, "we can predict that use of marijuana is going to increase," said Dr. Nora Volkow, director of the National Institute on Drug Abuse, which funds the annual study.
That pot has become more widely used as more states legalize the use of medical marijuana cannot be ignored, said R. Gil Kerlikowske, director of the White House Office of National Drug Control Policy.
"We know that any substance that is legally available is more widely used," he said.
The rise of marijuana use is largely responsible for an overall increase in youth drug use over the last four years, said study leader Lloyd Johnston of the University of Michigan's Institute for Social Research, which conducts the annual survey. When marijuana is taken out of the equation, the proportion of teens reporting they had used any illicit drug declined through the first half of the 2000s and has been stable over the last three years.
Since 1991, the proportion of eighth-grade students who said they had used alcohol within the last 30 days has declined by half, to 13%, the survey found. Rates have also fallen among older students, with binge-drinking among seniors dropping from 41% in 1981 to 22% this year. Still, about 40% of high school seniors said they had used alcohol within the last 30 days.
Cigarette use fell in all three age groups, which was reassuring since the 2010 survey hinted that the decades-long decline in smoking may have begun to reverse, Johnston said. In all three grades combined, 11.7% of youths said they had smoked within the last 30 days, down from 12.8% in the 2010 survey.
Declines were also seen in the use of inhalants, crack cocaine, the painkiller Vicodin, the medication Adderall for attention deficit hyperactivity disorder, and over-the-counter cold and cough medicines.
Use of prescription drugs without medical supervision remains a concern. In 2011, 22% of high school seniors said they had misused at least one prescription drug at some point in their lives — the same rate recorded in the 2007 survey. About 15% reporting misusing such drugs within the last year, compared with 16% in 2007.
"We are heartened by some of the results ... but there is much more work to do," said Dr. Howard K. Koh, assistant secretary for health for the Department of Health and Human Services.