Neurobiology of attention-deficit/hyperactivity disorder

Abstract

Biochemical, neurophysiological, radiological, nuclear-medicine, and molecular-genetic studies conducted to date on possible causes of attention-deficit/hyperactivity disorder (ADHD) suggest a genetically based dysfunction of catecholamines in the frontostriatal system. These disturbances in catecholamine regulation—dopamine appears to be particularly affected—lead to impairments in motor control, impulsivity, and stimulus perception and processing. For the first time, it was shown that the increased dopamine transporter density in the striatum of affected adults compared with controls can be markedly reduced by methylphenidate.