Modeling Adolescent Disposition Development: Age-Related Changes in Psychosocial Processes Correlated with Substance Use.

Purpose: A model is proposed in which longitudinal changes in adolescents' dispositions increase age-related risk for the onset of substance use.

Method: Pooled surveys from 25 longitudinal studies were examined. Disposition was calculated from eight variables: use intentions; refusal intentions; attitudes; positive consequence beliefs; beliefs about negative consequences; descriptive peer normative beliefs; injunctive peer normative beliefs; and lifestyle incongruence. Substance use onset (past 30-day alcohol, cigarette, and marijuana use) was analyzed using participants' just prior dispositional status and recent changes in their dispositions.

Results: Disposition was highly correlated with each of the measured variables. The pattern of disposition changes as adolescents grow older, revealing that younger adolescents have more positive dispositions; whereas when they grew older, negative dispositions gradually emerged among a subset of adolescents. Analyses also revealed that dispositional status and recent changes in their dispositions were strong predictors of substance use onset.

Implications: Better understanding the development of dispositions will aid in designing effective interventions. Subordinate variables are amenable to intervention and are recommended as the primary focus of prevention programming. Because of the developmental trajectory of dispositions, multi-year interventions are highly recommended. Whenever possible, tailored approaches that take adolescents' pre-intervention dispositions into account should be considered.