Hyperkinetic impulse disorder: a developmental defect of motivation.

An integrated, testable, bio-psychological theory which proposes that hyperkinetic impulse disorder (H.I.D.) is determined interactively by polygenically inherited and environmental factors is presented and examined in the light of the literature. The theory holds that H.I.D. is a developmental disorder of intrinsic motivation, characterized by poor appreciation of the contingencies between behavior and environmental events. Characteristics of H.I.D. children, including apparent overactivity, impulsivity, impersistence, inattention, and underachievement in academic and social skills, are accounted for, and implications for treatment and management are spelled out.