Objective: We sought to examine preliminary results of brain alterations in anterior cingulate cortex (ACC) in treatment-naive adults with ADHD. The ACC is a central brain node for the integration of cognitive control and allocation of attention, affect and drive. Thus its anatomical alteration may give rise to impulsivity, hyperactivity and…

Objective: To bridge theory of response inhibition and learning in children with ADHD. Method: Thirty ADHD and 30 non-ADHD children (ages 9-12) were compared under concurrent variable interval (VI-15 sec., VI-30 sec. and VI- 45 sec.) reinforcement schedules that required the child to switch between the three schedules under conditions of…

Background: The present study examined the distinct properties of executive functioning in relation to ADHD symptoms, as well as functional outcomes associated with ADHD. In line with the dual-pathway model of ADHD, executive functioning and delay aversion were expected to show independent effects on ADHD symptoms. Furthermore, relations to early…

Results indicated that learning disabled (LD) children performed less well than non-LD children on tasks requiring internal strategies or plans. With one exception, hyperactive and nonhyperactive LD children performed similarly. Across groups, children with more behavioral problems also were children who used less mature cognitive strategies.…

Thirteen preschool and first-grade hyperactive boys performed worse on communication tasks providing detailed cues only and responded more impulsively on tasks requiring additional cues than did 13 controls. Problems with detailed cues were not attributable to overall differences between groups in motivation, information requesting, processing…

Reports the results of a high-speed search task administered to overactive and distractible (hyperactives), normoactive and distractible, and normoactive and attentive (controls) children. Instructions emphasized speed, accuracy, or both speed and accuracy. Indicates that controls and distractibles conformed to the fast guess model, which relates…

Objective/Method: ADHD is often comorbid with anxiety disorders, with rates approaching 25% in many samples. This current review's goal is to examine the literature on ADHD with comorbid anxiety from 1998 to the present. Results: Recent studies indicate that anxiety in ADHD may a) partially inhibit the impulsivity and response inhibition deficits,…

This study investigated whether the stimulant methylphenidate (Ritalin) would differentially affect performance on a test of cognitive style by hyperactive children. Subjects were 55 children, (ages 7 to 15) referred to the Learning Clinic at the Hospital for Sick Children, Toronto, Canada for hyperactivity and/or learning problems. A paired…