Examines substance use between 10th and 12th grades in a predominantly African American sample of adolescents from an urban environment. Results indicate that low achievement and motivation, high truancy, and perception of peer substance use are associated with higher 10th grade substance use. Adolescents who perceive negative school attitudes among peers are more likely to increase cigarette and marijuana use. (Contains 81 references, 6 tables, and an appendix.) (GCP)