SPECT using N-Isopropyl I-123 IMP was performed, as part of a neuropsy
chiatric evaluation, on 10 patients with the DSM III-R diagnosis of At
tention Deficit Hyperactivity Disorder (ADHD) and 6 patients from a no
n-ADHD mixed psychiatric group used as controls for comparison. Mean r
egional I-123 IMP SPECT region of interest (ROI) count ratios (left to
right) demonstrated that the ADHD patients had greater overall hemisp
heric I-123 IMP uptake asymmetry with less activity in the left fronta
l and left parietal regions in comparison to control patients. Both gr
oups demonstrated similar I-123 IMP uptake asymmetry in the temporal r
egions. These findings are consistent with previous studies of brain p
hysiology in ADHD implicating regional cortical perfusion and metaboli
sm abnormalities in areas which are involved in the control of attenti
onal processes.