Background: For every year that drug use is delayed during adolescence, adult substance abuse rates could be reduced by up to 10 percent. Conventional school-based prevention programs have been hampered by relatively low success rates (e.g., one case of cannabis use prevented for every 33 children attending a program) and the need for intensive intervention (e.g., 15 to 30 sessions per program). Because certain personality traits such as impulsivity are linked to greater risks of substance abuse, a program targeting these traits might yield better success rates. Conrod and colleagues studied results that included analysis of illicit drug use at six, 12, 18, and 24 months in relation to interventions in adolescents to prevent drug use.

The Study: The authors recruited 732 adolescents 13 to 16 years of age who had elevated scores on personality traits linked to drug use, such as hopelessness, anxiety sensitivity, impulsivity, and sensation-seeking. Participants were randomized to a control or an intervention group in which they received two 90-minute group sessions. Sessions focused on how to cope with real-life drug use situations, and incorporated cognitive behavior therapy and motivational and psychoeducational components. Participants were followed for two years to assess the initiation of drug use. Exclusion criteria included reporting unreliable data (e.g., responding inconsistently to sham questionnaire items) or not providing parental consent for the interventions.

Results: Likelihood of starting marijuana use was not significantly affected by the intervention. However, adolescents in the intervention group were significantly less likely to start using cocaine (odds ratio [OR] = 0.2, number needed to treat [NNT] = 10) or other drugs (OR = 0.5, NNT = 16) at the end of two years compared with those in the control group.

Conclusion: The authors conclude that brief personality-targeted school interventions can prevent the onset of drug use among high-risk adolescents for up to two years, relative to a control group.