By Alan Mozes
FRIDAY, Oct. 24 (HealthDay News) -- Television ads that ran between 1999 and 2004 as part of the U.S. government's "National Youth Anti-Drug Media Campaign" do not appear to have dissuaded teens from smoking marijuana, a new study suggests.
In fact, researchers uncovered evidence indicating that the effort could possibly have had the reverse effect: sparking interest in marijuana among kids frequently exposed to the ads by implying that such drug use is common among their peers.
The study, led by Robert Hornik, from the Annenberg School for Communication at the University of Pennsylvania in Philadelphia, was expected to be published in the December issue of the American Journal of Public Health.
Hornik and his team noted that the campaign spent almost $1 billion through 2004 to market a national anti-drug message aimed at convincing youths to reject drugs such as marijuana and inhalants, prevent first-time use, and convince occasional users to stop. Heavy drug users, however, were not the campaign's target audience.
To gauge the ads' impact, the researchers analyzed data collected during an in-home survey of youths between the ages of 9 and 18.
The initial survey of more than 8,100 teens took place between 1999 and 2001, with three more follow-ups conducted with the majority of the participants through 2004.
In the survey, 94 percent of those polled said that they saw at least one to two ads a month, with a median exposure of two to three a week.
Among those teens between the ages of 12 and 18 who saw no more than four ads a month, 82 percent said they "definitely" had no plans to smoke marijuana.
Greater ad exposure, however, seemed to lead to diminishing returns. Among those who had seen at least 12 ads a month, only 78 percent expressed intentions not to smoke marijuana.
The researchers therefore concluded that although "the campaign was successful in achieving a high level of exposure to its messages, there is no evidence to support the claim that this exposure affected youth's marijuana use as desired".
Dr. Marc Galanter, director of the division of alcoholism and drug abuse in the department of psychiatry at New York University School of Medicine in New York City, cautioned that drug use is driven by a wide range of motivating influences, making it hard to link teen behavior directly to the messages of any one particular ad campaign.
"I don't think you can be clear about attributing changes in marijuana use to any single factor," he said. "But I also could imagine that the more kids are exposed to drug-related issues, the more they're aware of it, and the more it might spike some interest."
"So I think," added Galanter, "that it's certainly possible that exposing teens to drug-related video material, however it's framed or couched, might not do any good. And, conceivably, it could get some kids actually interested in drugs. But it's just very hard to know for sure."
Tom Riley, spokesman for the White House Office of National Drug Control Policy, suggested that the new survey was both old news and flawed in its rationale.
"This study is just the five-year version of the annual report that was published every year and actually paid for by the campaign to evaluate itself," he said. "So there's nothing new here. It's been reported many times, and there is no new data."
"What's more, the study doesn't emphasize that teen drug use started to go down in 2001," Riley added. He pointed out that overall drug use and marijuana use among teens dropped by 24 percent and 25 percent, respectively, since that time.
"I'm not saying there's a direct correlation here," Riley continued. "But the campaign started in 1998, so I don't think it's irrelevant, particularly because teens were the demographic targeted by this campaign, and other drug use hasn't changed in this time, while teen drug use has changed for the better dramatically."
"So today there are over 800,000 fewer teens using drugs than in 2001," he noted. "That's a huge difference. And there were no other significant programs or external phenomena aimed at that demographic in that period."