INHIBITION IN ADHD, AGGRESSIVE, AND ANXIOUS CHILDREN - A BIOLOGICALLY-BASED MODEL OF CHILD PSYCHOPATHOLOGY

In this study the stop signal task was employed to investigate inhibit ory control in 15 children with attention deficit hyperactivity disord er (ADHD), 18 aggressive and 20 anxious children, and a group of 17 no rmal controls. The psychopathological groups were recruited from speci al educational services. Parent, teacher, and child questionnaires wer e used to select children with pervasive disorders. Controls attended regular classes and scored low on all questionnaires. Based on Quay's model of child psychopathology (Quay, 1988, 1993), we hypothesized a d eficit in inhibitory control in children with externalizing disorders, whereas anxious children were predicted to be overinhibited. The ADHD group and the aggressive group showed poor inhibitory control and a s lower inhibitory process. No evidence of overinhibition was found in a nxious children.