Anti-drug public service announcements that feature teens using marijuana are less likely to dissuade viewers from experimenting with pot than are advertisements absent such images, according to survey data to be published in the journal Health Communication.

Investigators at the Annenberg School for Communication at the University of Pennsylvania assessed the attitudes of over 600 adolescents, aged 12 to 18, after viewing 60 government funded anti-marijuana service announcements. Specifically, researchers evaluated whether the presence of marijuana-related imagery in the ads (e.g., the handling of marijuana cigarettes or the depiction of marijuana smoking behavior) were more likely or less likely to discourage viewers’ use of cannabis.

Messages that depict teens associating with cannabis are “significantly less effective than others,” the researchers found.

“This negative impact of marijuana scenes is not reversed in the presence of strong anti-marijuana arguments in the ads and is mainly present for the group of adolescents who are often targets of such anti-marijuana ads (i.e., high-risk adolescents),” authors determined. “For this segment of adolescents, including marijuana scenes in anti-marijuana (public service announcements) may not be a good strategy.”

Since 1998, Congress has appropriated over $2 billion to fund anti-drug advertisements as part of the National Youth Anti-Drug Media Campaign. Independent reviews of the campaign have determined that the ads fail to discourage viewers from trying marijuana or other drugs.

In 2006, a study published in the journal Addictive Behaviors reported that teenagers who were most often exposed to the ad campaign were also most likely to hold positive attitudes about marijuana and were most likely to express their intent to use it.