Patterns of substance use in early through late adolescence.

This study examined patterns of substance use throughout adolescence. A cluster analytic approach was used to identify subgroups of adolescents on the basis of their levels of substance use from early through late adolescence (Grades 6 through 11). Six distinct clusters of substance users emerged-2 groups representing relatively stable patterns of substance use from early through late adolescence (ie., nonusers and alcohol experimenters), and 4 groups of users showing escalating patterns of substance use (i.e., low escalators, early starters, late starters, and high escalators). The study provides a comprehensive view of adolescent substance use by examining the progression of use from early to late adolescence, demonstrates the usefulness of studying patterns of use across multiple substances, and underscores the importance of building classification schemes based on repeated measurements of substance use to reflect changes over time. Implications of the findings for future research and for identifying high-risk subgroups of adolescents for purposes of intervention based on timing and pattern of escalation are discussed.