An interactional model explaining predisposition to hyperactivity asserts that being identified, diagnosed, and treated as hyperactive is a function of biological factors, early health and temperament, family characteristics, and the quality of the home environment. A longitudinal study involving 367 subjects, aged 17-18, tested the interactional model to determine the relative contributions of these factors during infancy, preschool, and elementary school years to a variety of adolescent outcomes. Patterns of individual characteristics and environmental process variables were found to be predictive of several adolescent outcomes. Early biological factors and the child's health and early temperament were predisposing for the adolescent mental health problems of depression, aggressive and nonaggressive conduct disorders, and hospitalization for psychological treatment. The effects of later familial, social, and cognitive factors were even more important in shaping educational outcomes. In other outcomes, such as substance use, delinquency, and alternate living situations, the early predisposing factors shared equally with the elementary school variables in explaining the outcomes. (Six pages of references and three tables are provided.) (JDD)