Notes. Numbers on paths are unstandardized coefficient (SE)/standardized coefficient. For clarity of presentation, the age covariate as well as the following covariances among study variables are not shown: Friend substance use at Wave 2 ↔ Adolescent substance use at Wave 2 = .62***; Friend substance use at Wave 2 ↔ Adolescent impulsivity at Wave 2 = .40***; Adolescent impulsivity at Wave 2 ↔ Adolescent substance use at Wave 2 = .39***; Friend substance use at Wave 3↔ Adolescent substance use at Wave 3 = .45***; Friend substance use at Wave 3 ↔ Adolescent impulsivity at Wave 3 = .23**; Adolescent impulsivity at Wave 3↔ Adolescent substance use at Wave 3 = .22**; Age at Wave 1 → Adolescent substance use at Wave 1 = .29***; Age at Wave 1 → Adolescent substance use at Wave 2 = .23**; Age at Wave 1 → Adolescent substance use at Wave 3 = .02; Age at Wave 1 → Friend substance use at Wave 2 = .45***; Age at Wave 1 → Friend substance use at Wave 3 = .19** * p < .05; ** p < .01; ***p < .001.

Figure 1: Results of the longitudinal associations among adolescent impulsivity, friend substance use, and adolescent substance use.

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