Neurobiology of attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is an early-onset, clinically and presumably etiologically heterogeneous disorder characterized by inattention, hyperactivity, and impulsivity. Although the specific neurobiological basis of ADHD remains unknown, research in the fields of genetics, adverse environmental factors, neuropsychology, psychophysiology, neuroimaging, and neurochemistry has made substantial progress and several models of the underlying pathophysiology have been suggested. This comprehensive review summarizes the relevant findings in these various areas and provides an update of current knowledge concerning the pathophysiology of ADHD.