Having friends who use drugs and support drug use in relationships is the most robust predictor of substance use during adolescence (e.g., Dishion and Owen 2002; Elliott et al. 1985; Hawkins et al. 1992). This strong association likely relies on several mechanisms, including influence and selection effects (e.g., Dishion and Owen 2002; Kandel 1978; Steglich et al. 2010). Adolescents who associate with substance-using peers are exposed to substance use and have increased opportunities for use. Furthermore, peer groups are likely to shape adolescents’ attitudes about substance use, and those youth who associate with substance-using peers demonstrate more favorable attitudes about use (Hawkins et al. 1992).
