Abnormal executive function in attention deficit hyperactivity disorder: the effect of stimulant medication and age on spatial working memory

Objective. This study sought to examine the factors associated with spatial working memory and the use of strategies to impairment!, in spatial workin g memory in children with attention deficit hyperactivity disorder (ADHD). The developmental trajectories for spatial working memory in medicated and medication naive children with ADHD were investigated. In addition, the eff ect of psychostimulant medication on deficits in spatial working memory was examined. Method. A cross-sectional study compared performance between 21 psychostimu lant medicated children with ADHD, 27 medication naive children with ADHD a nd 26 matched control subjects on computerized tests of spatial memory and spatial working memory. Results. Compared with the controls, performance in medication naive childr en with ADHD was significantly worse on the spatial working memory task. Th ere was no difference in performance between the medicated children with AD HD and the control subjects on this same task, despite the ongoing symptoms of ADHD in the former group. The pattern of normal and abnormal performanc e in the ADHD groups was age-independent, Conclusions. Deficits in executive functions related to spatial working mem ory do occur in children with ADHD, although the magnitude of these deficit s is not related to the child's age or the level of ADHD symptoms. These de ficits were not present in the current sample of children who were receivin g psychostimulant medication.