Circulatory levels of catecholamines, serotonin and lipids in attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) may be associated with a dy sregulation of the catecholaminergic and serotonergic systems. Furthermore, ADHD is frequently complicated by aggressive impulsive behaviour, which is suggested to be related to low serum cholesterol levels. We examined the r elationship between blood serotonin, norepinephrine, dopa and lipid levels and the degree of hyperactivity, impulsiveness, lack of concentration, and aggressiveness in boys with ADHD of low and high severity as determined by a specially designed formulated scale based on the DSM-IV criteria for ADHD , No differences were noted between the groups in any of the peripheral bio logical parameters except blood serotonin, for which a tendency (P=0.08) to wards lower levels was observed in the children with more severe disorder. We conclude that children with severe ADHD may have a different serotonin t urnover compared to children with mild ADHD. These results may have implica tions for our understanding of the pathogenesis of ADHD, at least the more severe type.