RESUMEN
OBJECTIVE: To examine the joint influences of parental monitoring and peer influence on adolescent substance use over time. SUBJECTS: 6500 adolescents attending six high schools in Wisconsin and northern California. DESIGN: Longitudinal study. RESULTS: Parental monitoring was negatively associated with substance use, whereas the more involved an adolescent's peers were in substance use, the more likely he or she also was to use drugs and alcohol. Effects of monitoring and peer coercion were strongest for boys and girls at the transition into substance use, rather than at the transition from experimentation to regular use. The effect of parental monitoring on changes in adolescent substance use is mediated not so much by the nature of the adolescent's peer associates, but by its direct effect on the adolescent. Specifically, poorly monitored adolescents are more likely to use drugs, and drug-using adolescents seek out like-minded friends. Once an adolescent associates with drug-using peers, his or her own substance use approaches their level. CONCLUSIONS: Intervention effects should include both parents and community-level efforts. Parental monitoring is an effective tool both in the prevention of drug use and in the amelioration of drug use.