The numbers prompt a call for "proactive" response.
Synthetic drugs once touted as legal alternatives to marijuana have gained a foothold among teenagers, with one in nine high school seniors surveyed last spring saying they had used so-called synthetic pot in the previous year.
The study, released Wednesday by the National Institutes of Health, is believed to be the first government attempt to survey the popularity of synthetic substances often marketed as "herbal incense" and sold under brands such as "Spice" and "K2."
"We actually were very surprised that the numbers were so high," said Dr. Nora Volkow, director of the National Institute on Drug Abuse, which sponsors the annual "Monitoring the Future" survey.
Volkow said the numbers suggest either the drug's use went undetected by officials for a while, or its rate of acceptance is rising rapidly. She said the data indicates the government must be "proactive" in dealing with the problem.
Senior students with the highest rate of use -- 13.5 percent -- were from the Midwest.
"Perhaps the rates are higher in the Midwest because people don't want to be lawbreakers, they think that it is legal and therefore they aren't doing anything wrong," said Carol Falkowski, drug abuse strategy officer for the Minnesota Department of Human Services. "There are numerous websites that still portray these products and say they're 100 percent legal."
The survey, based on responses from 47,000 students in grades 8, 10 and 12, showed that alcohol and cigarette use are at an all-time low since the survey began 37 years ago.
Fake pot was the second-most frequently used illegal drug behind natural marijuana, which 36.4 percent of seniors reported using in the same time period, according to the study. Frequent use of marijuana reached a 30-year peak among high school seniors. More than 90 percent of synthetic pot users surveyed said they had also used natural marijuana.
"One in every 15 high school seniors today is smoking pot on a daily or near-daily basis," said Lloyd Johnston, principal investigator of the study.
Fakes still available
Herbal incense was among the first in a wave of new designer drugs to hit the market in the United States. Later, cocaine-like stimulants labeled as "bath salts" became popular, as well as psychedelic "research chemicals."
U.S. Poison Control Centers took 2,915 calls about synthetic marijuana in 2010. In the first 10 months of this year, the calls had almost doubled, reaching 5,741.
In March, the U.S. Drug Enforcement Administration (DEA) temporarily banned five chemicals found in synthetic marijuana. At least 40 states have passed laws or implemented rules banning some chemicals related to synthetic marijuana, according to the National Conference of State Legislatures. The U.S. House passed a ban last week.
Despite efforts to limit access to synthetic drugs, they are still widely available on the Internet and also sold in some stores. Some manufacturers have switched to legal chemicals similar to those banned.
Some teens and young adults turned to synthetic marijuana to avoid detection by parents, employers, coaches and probation officers, treatment officials said.
Paul McGlynn, executive director of Sobriety High charter schools in Coon Rapids and Burnsville, said he first heard of synthetic marijuana more than two years ago, just as it was beginning to emerge locally. Students in his English class talked about "K2" right in front of him, he said.
"They were all so comfortable talking about it because it was legal," he said.
Student Joseph Fischer, 18, said he tried it nearly three years ago. "I was, like, the person who wanted to see if you could do drugs and not get caught. I looked up a lot of laws," he said.
Fischer said fake pot made him feel lost and paranoid. Sober now, he said he stopped experimenting with it after his mother, a paramedic, told him about responding to teenagers who fell ill after using it.
Across the country, synthetic marijuana users have reported episodes of feeling sick, and in some cases psychotic and suicidal. Volkow said the survey results will likely open the door to more study of the drug's use.
Dr. Joseph Lee, medical director of the Youth Continuum at Hazelden, said he's seen synthetic use continue despite bans. Some teens and young adults read about synthetics on the Internet and use that information as social currency, he said.
"A lot of kids feel overly confident because they read a number of things on websites," Lee said. Then they act like drug experts to their friends, he said. "These kids are really a problem because they give bad advice to other kids. They're not doing it on purpose, they're just doing it to be accepted socially."
White House drug czar R. Gil Kerlikowske called the new survey results "shocking." In an interview, he said he believes synthetic drug use could be curbed with laws making the drugs less available. He also urged parents to become more involved.
"I'm not so sure that parents and others that take care of kids, or mentor and monitor the kids, are even aware of K2 and Spice," Kerlikowske said. "The real key, of course, will be to be able to get a workable law that doesn't have to be tweaked every time somebody changes the chemical compound."
Pam Louwagie • 612-673-7102