Abstract
PURPOSE: This study examined the changes in friends' and parental influences on cigarette smoking across two developmentally distinct social environments for adolescents: junior high school and high school. METHODS: Longitudinal data consisting of seven repeated measures following 1,001 adolescents from 7th to 12th grade was obtained from the Midwestern Prevention Project. A two-piece Growth Curve Model (GCM) was used to assess the growth trajectory of current cigarette use: one piece for the junior high school period, and the other for the high school period. Perceived friends' and parental cigarette use were each used as a time-varying covariate in separate GCMs. RESULTS: Effects of friends' and parental cigarette use remained significant on adolescent cigarette smoking across the two developmental periods. The magnitude of friends' effect was in general higher during junior high school than high school. The magnitude of the parental effect remained relatively stable between the two periods. However, decreasing trends in both effects were observed from 10th to 12th grade. Gender differences also emerged. Friends' and parental effects were greater for girls in their early high school years, whereas friends' effect decreased in magnitude among girls and increased among boys during high school. CONCLUSIONS: The transition from junior high school to high school represents an opportunity for interventions to counteract peer influence given that such influence appeared to be much weaker during this period. However, interventions should continue to target parents as their behavior remains influential through the end of high school.