Just say no. In 1982 First Lady Nancy Reagan uttered those three words in response to a schoolgirl who wanted to know what she should say if someone offered her drugs. The first lady's suggestion soon became the clarion call for the adolescent drug prevention movement in the 1980s and beyond. Since then, schools around the country have instituted programs designed to discourage alcohol and drug use among youthmost of them targeting older elementary schoolchildren and a few addressing adolescents.

There is good reason for concern about youth substance abuse. A large U.S. survey conducted in 2012 by psychologist Lloyd D. Johnston and his colleagues at the University of Michigan revealed that fully 24 percent of 12th graders had engaged in binge drinking (defined as five or more drinks on one occasion) in the past two weeks. Moreover, 42 percent had consumed at least some alcohol in the past month, as had 11 percent of eighth graders and 28 percent of high school sophomores. In addition, 1 percent of 12th graders had tried methamphetamine, and almost 3 percent had used cocaine in the past year.

In an attempt to reduce these figures, substance abuse prevention programs often educate pupils regarding the perils of drug use, teach students social skills to resist peer pressure to experiment, and help young people feel that saying no is socially acceptable. All the approaches seem sensible on the surface, so policy makers, teachers and parents typically assume they work. Yet it turns out that approaches involving social interaction work better than the ones emphasizing education. That finding may explain why the most popular prevention program has been found to be ineffectiveand may even heighten the use of some substances among teens.

Rehearsing Refusal
The most widely publicized teen substance abuse prevention program is Drug Abuse Resistance Education, better known by the acronym D.A.R.E. Created in 1983 by the Los Angeles Police Department, D.A.R.E. asks uniformed police officers to go into schools to warn students about the dangers of drug use and underscore the pluses of a drug-free way of life. In most cases, the officers do so once a week, typically for 45 to 60 minutes, for several months. D.A.R.E. is immensely popular; according to the program Web site, it has been put in place in 75 percent of U.S. school districts and 43 countries. D.A.R.E. bumper stickers, D.A.R.E. T-shirts, and police cars emblazoned with the word D.A.R.E. are familiar fixtures in many U.S. communities.

Despite this fanfare, data indicate that the program does little or nothing to combat substance use in youth. A meta-analysis (mathematical review) in 2009 of 20 controlled studies by statisticians Wei Pan, then at the University of Cincinnati, and Haiyan Bai of the University of Central Florida revealed that teens enrolled in the program were just as likely to use drugs as were those who received no intervention.

A few clues to D.A.R.E.'s deficiencies come from psychologist Pim Cuijpers of the Netherlands Institute of Mental Health and Addiction in Utrecht. In a review of 30 studies published in 2002, she attempted to pinpoint the common elements of successful programs. Cuijpers reported that the most effective ones involve substantial amounts of interaction between instructors and students. They teach students the social skills they need to refuse drugs and give them opportunities to practice these skills with other studentsfor example, by asking students to play roles on both sides of a conversation about drugs, while instructors coach them about what to say and do. In addition, programs that work take into account the importance of behavioral norms: they emphasize to students that substance use is not especially common and thereby attempt to counteract the misconception that abstaining from drugs makes a person an oddball.

In a 2011 review of various substance abuse prevention programs, epidemiologist Melissa Stigler of the University of Texas School of Public Health and her colleagues buttressed these conclusions. They further observed that programs that unfold during many sessionsideally, over several yearsgarner especially strong results, probably because they provide students with lessons that are reinforced over time, as children mature and encounter different environments.

D.A.R.E. lacks some of these key elements. It typically lasts only months rather than years. Moreover, it affords students few opportunities to practice how to refuse offers of drugs. Indeed, Cuijpers noted that purely educational programs that involve minimal or no direct social interaction with other students are usually ineffective. Merely telling participants to just say no to drugs is unlikely to produce lasting effects because many may lack the needed interpersonal skills. Programs led exclusively by adults, with little or no involvement of students as peer leadersanother common feature of D.A.R.E.seem relatively unsuccessful, again probably because students get little practice saying no to other kids.

Good Intentions That Backfire
Worse, D.A.R.E. programs might occasionally backfire when it comes to the use of milder substances, such as alcohol and cigarettes. In a 2002 review psychologist Chudley Werch, now president of PreventionPLUSWellness in Jacksonville, Fla., and health educator Deborah Owen of the University of North Florida reported a slight tendency for teens who went through D.A.R.E. to be more likely to drink and smoke than adolescents not exposed to the program. Small negative effects for D.A.R.E.-like programs on drinking and smoking were also reported in a 2009 study by public health professor Zili Sloboda of the University of Akron and her colleagues. The reasons for these potential boomerang effects are unclear. Yet by emphasizing the hazards of severe drug abuse, D.A.R.E. may inadvertently convey the impression that alcohol and tobacco are innocuous by comparison.

These scientific findings stand in stark contrast to the belief, held by scores of schoolteachers and parents, that D.A.R.E. works. One reason for this discrepancy, clinical psychologist Donald R. Lynam, now at Purdue University, and his colleagues wrote in a 1999 article, is that teachers and parents may overestimate the prevalence of substance use among children. As a consequence, they may assume a decline in use when students of D.A.R.E. abstain from alcohol and drugs. But that conclusion is erroneous if children who did not receive drug prevention education display levels of drug use that are just as low, if not lower. In addition, as Lynam and his colleagues observe, D.A.R.E. makes intuitive sense: it seems plausible that most children exposed to authority figures who warn that drug use is dangerous would hesitate to disobey those admonitions.

The good news is that some proponents of D.A.R.E. are now heeding the negative research findings and incorporating potentially effective elements, such as role playing with peers, into the intervention. Research on these revised programs should soon tell us whether they will make a dent in the considerable problem of substance abuse among vulnerable youth.