By Rita Rubin, USA TODAY
More high school seniors this year used marijuana than smoked cigarettes in the past 30 days, according to government data released Tuesday.
In addition, daily marijuana use increased significantly among eighth-, 10th- and 12th-graders, with about one in 16 high school seniors using marijuana daily or near-daily, the annual "Monitoring the Future Survey" found.
Teens in all three grades exhibited more favorable attitudes toward the drug, according to the national survey of more than 46,000 teens.
The survey's lead investigator, the director of the National Institute on Drug Abuse (NIDA), and the White House "drug czar" blamed the rising use among teens in the past three years on publicity surrounding medical marijuana.
"Young people are increasingly seeing marijuana as not dangerous," said lead investigator Lloyd Johnston of the University of Michigan's Institute for Social Research. When the proportion of teens who view marijuana as risky declines, Johnston says, use typically increases.
Marijuana use by teens declined from 2002 to 2007, noted Nora Volkow, director of the National Institute of Drug Abuse. But today's eighth-graders "have been exposed to a very different perspective on the way that the world is looking at marijuana."
More than a dozen states and the District of Columbia have legalized medical marijuana, so teens might tend to view the drug as beneficial, not risky, Volkow said.
She said marijuana interferes with memory and learning, which is of particular concern in teens, whose brains aren't yet fully developed. Volkow said her institute plans to fund research into whether U.S. students' grades and test scores have fallen as marijuana use has increased.
"I don't have any hesitation telling you that I think the legitimizing of marijuana and calling it medicine is absolutely the wrong message to give to young people," White House drug czar R. Gil Kerlikowske said.
His daughter lives in Colorado, where medical marijuana is legal. When she drives his granddaughter, a high school freshman, past marijuana dispensaries, "it's a tough explanation," Kerlikowske said.
According to the National Cannabis (marijuana) Industry Association, a new lobbying group in Washington, "thousands of American businesses are involved in some fashion in the cannabis industry."
Marijuana wasn't the only drug that teens increasingly used this year, the survey found. Ecstasy use rose in all three grades, with significant increases among eighth- and 10th-graders. The younger teens may not remember stories about casualties related to Ecstasy, whose use peaked in 2001 and then dropped sharply for about four years, Johnston said.
Use of narcotics other than heroin hasn't changed significantly since 2004, when 9.5% of 12th-graders had used the drugs in the previous year - nearly three times as many as in 1992. Injecting heroin with a needle showed a small but statistically significant increase in 2010, but it's still so uncommon in teens that Johnston said he can't yet be sure that use is growing.