The Milwaukee Longitudinal Study of Hyperactive (ADHD) Children followed a large group of children with hyperactive child syndrome (now ADHD Combined Presentation) along with a control group of typically developing children into young adulthood (mean age 27 years) assessing them at four points in development: childhood, adolescence (mean age 15 years), emerging adulthood (mean age 20 years), and young adulthood. A wide variety of measures were used to evaluate numerous domains of cognitive, adaptive, family, peer, educational, occupational, financial, sexual, driving, and health-related variables. Results revealed numerous differences between the groups at each follow-up point, culminating in the conclusion that ADHD is an impairing disorder across many if not all of these domains, persisting into young adulthood in at least two thirds or more of affected childhood cases, depending on the definitions of recovery and persistence.