Abstract

A review of over thirty neuroimaging studies on children diagnosed with Attention Deficit/Hyperactivity Disorder by Giedd, Blumenthal, Molloy, and Castellanos is organized around tables listing the main findings of studies using different types of neuroimaging. Like most researchers in this field, Giedd et al. conclude that the evidence supports the involvement of right frontal–striatal circuitry with cerebellar modulation in ADHD. However, Giedd et al. do not report on a confounding variable of crucial interest in this field of research — whether subjects had been previously treated with stimulants or other psychotropic drugs. In the present paper, we have redone five of the tables from the Giedd et al. review, adding information on the subjects’ prior medication exposure, as reported in the individual studies included in the review. We found that most subjects diagnosed with ADD or ADHD had prior medication use, often for several months or years. This substantial confound invalidates any suggestion of ADHD-specific neuropathology. Moreover, the few recent studies using unmedicated ADHD subjects have inexplicably avoided making straightforward comparisons of these subjects with controls.