Attention-deficit hyperactivity disorder (ADHD) is a serious neuropsychiatric problem in schoolchildren (an estimated 3-6% of US schoolchildren are affected, for example). The disorder is characterised by poor attention span, impulsivity, and high motor activity. Its nature and cause are poorly understood, although previous research has suggested that structural changes in areas of the brain controlling attention are responsible for the disorder.

Elizabeth R Sowell, Assistant Professor of Neurology from the Laboratory of Neuro Imaging at the University of California Los Angeles, USA, and colleagues undertook the first detailed morphological study using high-resolution magnetic resonance imaging (MRI) and sophisticated computational systems to more accurately determine the specific areas of the brain underlying ADHD. Brain assessment of 27 children (11 girls, 16 boys) and adolescents with ADHD was compared with that of 46 control children without ADHD who were matched for age and sex.

Abnormal brain structure was observed in the frontal cortices (on both sides of the brain) of children with ADHD, with reduced regional brain size localised mainly to small areas of the dorsal prefrontal cortices. Children with ADHD also had reduced brain size in anterior temporal areas, also on both sides of the brain. Substantial increases in grey matter were recorded in large portions of the posterior temporal and inferior parietal cortices in children with ADHD.

Elizabeth R Sowell comments: "Our morphometric procedures allow more precise localisation of group differences than do the methods used in previous studies. Our results therefore suggest that the disturban
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Contact: Joe Santangelo
j.santangelo@elsevier.com
212-633-3810
Lancet
20-Nov-2003