Peer substance use as a mediator between early pubertal timing and adolescent substance use: longitudinal associations and moderating effect of maltreatment.

Background: Early pubertal timing has received considerable empirical support as a risk for adolescent substance use. However, few studies have examined the mediators linking these variables. Therefore, the aims of this study were (1) to examine peer substance use as a mediator between pubertal timing and adolescent substance use longitudinally and (2) to test gender and maltreatment experience as moderators of the mediational model.

Methods: Data were obtained from time 1, 2, and 3 of a longitudinal study of maltreatment and development. At time 1 the sample was comprised of 303 maltreated and 151 comparison children aged 9-13 years (213 females and 241 males). Longitudinal mediation was tested using structural equation modeling and moderating effects were tested using multiple group analysis.

Results: Peer substance use mediated the relationship between early pubertal timing and later adolescent substance use for the total sample. Moderation analyses indicated this significant indirect effect did not differ for males and females. However, it did differ for maltreated versus comparison adolescents with the mediational effect only remaining significant for the comparison group.

Conclusions: This is one of the first studies to examine peer substance use as a mediator of pubertal timing and adolescent substance use using a longitudinal design. Early maturing males are at equal risk to early maturing females for interacting with peers that may draw them into substance use. Additionally, the findings indicate that while peers are mediators for comparison adolescents a different mechanism may link early puberty to substance use for maltreated adolescents.