After a decade of declining drug use among US teens, dependence on alcohol, marijuana, and Ecstasy is reported to be on the rise.

The reversal in the trend line is startling to drug-prevention advocates, who say high-profile media campaigns and parental involvement helped to curb all categories of teen drug use between 1998 and 2008. In 2008, for example, use of alcohol and marijuana decreased 30 percent among ninth and 12th graders from the year before; methamphetamine abuse was down 60 percent.

These findings, published last week by the Partnership for a Drug Free America and the MetLife Foundation, show that teen usage swung back up last year for the first time since 1998. Another study released late last year, by the federal government, also showed rising use of marijuana among certain teen subsets.

Among the findings released this week regarding teens between the ninth and 12th grades:

• Yearly and monthly marijuana use increased to 38 and 25 percent, respectively.

• Teen alcohol use grew to 39 percent from the previous year, an 11 percent rise.

• Thirteen percent of teens say they tried Ecstasy last year, a 30 percent increase from 2008.

• Seventy-five percent of teenagers say they have friends who get high at parties, a 9 percent increase from 2008.

Partnership Strategy director Sean Clarkin cites several reasons for the dramatic reversal: a continuing decrease in federal funding for drug-prevention programs in schools and the media, the public conversation about the legalization of marijuana, and “the growing proliferation of pro-drug cues in popular culture,” particularly online.

“You can go on YouTube and there are a zillion videos of kids getting high,” says Mr. Clarkin. “We see that borne out in some of the data around kids’ attitudes about drugs. They find it more normal to use because they say their friends use more frequently, so they expect to use in more social situations.”

Inhalants, such as glues, nail polish remover, spray paints, and cleaning fluids, pose a growing risk among teens, the use of which peaks in eighth grade, Clarkin says. A report this week by the US Substance Abuse and Mental Health Services Administration reported that from 2006 to 2008, 7 percent of 12-year-olds sniffed inhalants – usage that is particularly steep compared with the 1.4 percent who say they used marijuana or the 0.1 percent who used cocaine.

Inhalants are considered particularly dangerous because they are cheap, readily available, and public awareness among parents is relatively muted. Unlike some other drugs, inhalants can cause death even among first-time users.

In recent years, reports have shown that teen access to drugs, especially prescription medicines, is easier than ever.

More permissive attitudes among teens toward drug use can be combated through education campaigns in schools and through the media, both of which have atrophied, Clarkin says. School and the home “are the two areas kids are going to spend a bulk of their time,” he says. “So to basically have pro-drug cues picked up from their peers and the media, uncontested by any kind of antidrug messaging, is problematic.”