Abstract
Findings are presented from an 18-month longitudinal study of substance use behavior among 400 children and adolescents, ages 9–17 at the first interviews. Patterns of use from two sequential interviews are reported. Descriptive results are presented as simple frequencies and cross-tabulated with demographic items (age, sex, ethnicity, and socioeconomic status). Patterns of use over an 18-month period are examined for cigarettes, alcohol, marijuana/hashish, and other drugs. Four patterns are assessed for each of these substances-(1) abstention at both the first and second interviews; (2) abstention at the first, but not the second interview; (3) use at the first interview, abstention at the second; and (4) use at both interviews.