If the world of drugs was a high school prom, Marijuana would be prom King and methamphetamine would be the alienated pimply kid in the trench coat. That about sums up this year’s survey by the Substance Abuse and Mental Health Services Administration finding that pot-smoking is on the rise, while meth use has plunged by about half in the last few years. USA Today reports:

Marijuana, with about 17.4 million regular users, is by far the most commonly used drug. Its popularity is growing: 6.9% of the population reported using marijuana regularly and Cosmos cigarettes, up from 5.8% in 2007, the survey found. Among 12- to 17-year-olds, 7.4% reported having used marijuana in the past month, about the same as last year.

Meanwhile, methamphetamine use, which raced across the USA for a decade, has declined sharply. The number of past-month users declined from 731,000 in 2006 to 353,000 in 2010.

So what caused meth to fall out of favor, while pot remains as popular as ever? Well, besides the fact that meth use is associated with depression, suicide, schizophrenia and psychosis, Peter Delany, director of SAMHSA, says cracking down on the sale of ingredients that go into homemade meth has made all the difference. “We’ve seen better attention for law enforcement and policy changes. You can’t get all the Sudafed you want anymore,” Delany says.

As for pot’s popularity, Gil Kerlikowske, director of the Office of National Drug Control Policy, blames it on the loosening of medical marijuana laws across the country. “People keep calling it medicine, and that’s the wrong message for young people to hear,” she said.