Psychological Medicine

Original Article

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

R.  BARNETT  c1 a1, P.  MARUFF  a1, A.  VANCE  a1, E. S. L.  LUK  a1, J.  COSTIN  a1, C.  WOOD  a1 and C.  PANTELIS  a1
a1 From Maroondah Hospital Child and Adolescent Mental Health Service; Department of Psychological Medicine, Monash University; School of Psychological Science, La Trobe University; Mental Health Institute of Victoria and Department of Psychiatry, University of Melbourne, Victoria, Australia


Objective. This study sought to examine the factors associated with spatial working memory and the use of strategies to impairments in spatial working memory in children with attention deficit hyperactivity disorder (ADHD). The developmental trajectories for spatial working memory in medicated and medication naïve children with ADHD were investigated. In addition, the effect of psychostimulant medication on deficits in spatial working memory was examined.

Method. A cross-sectional study compared performance between 21 psychostimulant medicated children with ADHD, 27 medication naïve children with ADHD and 26 matched control subjects on computerized tests of spatial memory and spatial working memory.

Results. Compared with the controls, performance in medication naïve children with ADHD was significantly worse on the spatial working memory task. There was no difference in performance between the medicated children with ADHD and the control subjects on this same task, despite the ongoing symptoms of ADHD in the former group. The pattern of normal and abnormal performance in the ADHD groups was age-independent.

Conclusions. Deficits in executive functions related to spatial working memory do occur in children with ADHD, although the magnitude of these deficits is not related to the child's age or the level of ADHD symptoms. These deficits were not present in the current sample of children who were receiving psychostimulant medication.

c1 Address for correspondence:Rebecca Barnett, Neurophysiology and Neurovisual Research Unit, Mental Health Research Institute of Victoria, Parkville, VIC 3052, Australia.