title: Platelet serotonin concentration in children with attention-deficit/hyperactivity disorder.
abstract: BACKGROUND
  Attention-deficit/hyperactivity disorder (ADHD) is a psychiatric disorder highly prevalent in children. The neurobiology of ADHD is still not clear, but is assumed to be related to disturbances in catecholaminergic and serotonergic (5-hydroxytryptamine, 5-HT) systems. Peripheral indices of central 5-HT function were shown in recent studies to be lower, unaltered, or increased in ADHD.
  
  
  METHODS
  The study determined platelet 5-HT concentration in 84 medication-free 9-year-old (range 4-14 years) boys and girls with DSM-IV diagnosis of ADHD, subdivided according to the different symptoms (inattention, hyperactivity, and impulsivity) and clinical ADHD subtypes (predominantly hyperactive, predominantly inattentive, and combined subtype), and in 30 age- and sex-matched healthy controls.
  
  
  RESULTS
  Children with ADHD had similar platelet 5-HT concentrations to control children. Platelet 5-HT concentration did not differ between boys and girls, or between children with a hyperactive, inattentive, or combined subtype of ADHD. In children with ADHD there was a significant positive correlation between platelet 5-HT concentration and impulsive symptoms, but not with symptoms of inattention or hyperactivity.Platelet 5-HT concentration wassignificantly higher in impulsive compared to non-impulsive children with ADHD.
  
  
  CONCLUSIONS
  The data provide preliminary evidence that increased platelet 5-HT concentration might be a trait marker predictive of impulsivity in ADHD.
authors.affiliation: Polyclinic Kocijan/Hercigonja, Zagreb, Croatia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Hercigonja Novkovic
authors.forename: Vlasta
authors.initials: V
authors.lastname: Rudan
authors.forename: Nela
authors.initials: N
authors.lastname: Pivac
authors.forename: Gordana
authors.initials: G
authors.lastname: Nedic
authors.forename: Dorotea
authors.initials: D
authors.lastname: Muck-Seler
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000097:blood* / Q000523:psychology; D001792:Blood Platelets / Q000737:chemistry*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000097:blood*; D008297:Male; D012701:Serotonin / Q000097:blood*; D012727:Sex Characteristics
chemical_list: D012701:Serotonin