Two subgroups of hyperactive children (25 non-delinquent and 9 delinquent) and 1 group of 34 non-delinquent normal children were evaluated from childhood to adolescence at the National Center for Hyperactive Children, Encino, CA, using auditory evoked response potential (AERP) measures and EEG recordings. Abnormalities of CNS maturation and function relected by longitudinal AERP changes and abnormal EEGs characterized the non-delinquent hyperactive subjects, while delinquent hyperactive subjects showed normal maturational changes. ADDH boys with neurologic abnormalities had a better outcome than those with normal CNS functions who later became delinquent and whose behavior was presumed secondary to environmental social factors. Two distinct subgroups of ADDH, one with and one without delinquency, were lineated. [1]