Attention deficit disorder with and without hyperactivity: reaction time and speed of cognitive processing.

This study addressed the issue as to whether children reliably diagnosed as attention deficit disordered with hyperactivity (ADD/H) and without hyperactivity (ADD/WO) differed significantly from each other and a clinic control (CC) population on speed and efficiency of cognitive processing. From an outpatient clinic population, 43 ADD/H and 22 ADD/WO children were examined. An analysis of mean reaction time and speeded classification task performance revealed significant group effects on both mean reaction time and on a measure of within-subject variability. ADD/H children performed significantly more slowly and variably than the CC children on several of the speeded classification tasks. However, the ADD/WO group was not distinguished on any measure. Thus, while children may be reliably diagnosed as ADD/H or ADD/WO using behavioral measures, it would appear that they cannot be distinguished on these neurocognitive tasks. Issues related to childhood psychopathology and the neuropsychological basis of ADD/H are discussed.