Volumetric MRI differences in treatment-naive vs chronically treated children with ADHD

Objective: To determine if there are differences in the volume of the caudate and anterior cingulate cortex (ACC) between children with attention deficit hyperactivity disorder (ADHD) and controls, and if such differences are related to the subjects' history of stimulant treatment. Methods: We performed a case-control study in an academic medical center. Twenty-one healthy controls, 16 children with ADHD, combined type with a history of stimulant treatment, and 14 children with ADHD, combined type treatment naive, underwent structural MRI. All children with ADHD were medication-free at the time of the MRI. Regional hemispheric volumes (in cm(3)) of caudate and anterior cingulate cortex were determined. Results: There were significant differences bilaterally on caudate volume for both ADHD groups vs controls, with no difference between the ADHD groups on either side. In contrast, the right ACC was significantly smaller for the ADHD-treatment naive (ADHD/TN) group compared to the ADHD-treated (ADHD/Rx) and control group. The volume of left ACC approached significance contrast between ADHD/RX and ADHD/TN. There were no differences found between the ADHD/Rx and controls on the ACC volumes bilaterally. Conclusions: The results from this study indicate a relationship of previous treatment history with caudate and anterior cingulate volumetric changes in children with attention deficit hyperactivity disorder-combined type.