title: Diminished 5-HT functioning in CBCL pediatric bipolar disorder-profiled ADHD patients versus normal ADHD: susceptibility to rapid tryptophan depletion influences reaction time performance.
abstract: OBJECTIVE
  There is a current debate on characterizing children with pediatric bipolar disorder (PBD) through a profile within the child behaviour checklist (CBCL), and on the involvement of the 5-HT system in the underlying neurobiological processes of PBD. The aim of the present paper was to investigate reaction time performance in patients with CBCL-PBD and to discriminate ADHD from ADHD with CBCL-PBD with respect to diminished 5-HT functioning and reaction time.
  
  
  METHODS
  Twenty-two patients with ADHD received the rapid tryptophan depletion test (RTD) thus lowering the central-nervous 5-HT synthesis rate within a placebo-controlled double-blind within-subject crossover design. Reaction time was assessed using a competitive reaction time game with low and high provocation after both depletion and placebo intake. The study sample was divided into high and low scorers according to their CBCL-PBD scores.
  
  
  RESULTS
  Comparing those six patients with the highest and clinically significant CBCL-PBD scores versus those six patients with the lowest, patients with a high CBCL-PBD score showed a slower reaction time under RTD compared to patients with low CBCL-PBD scores after high provocation. CBCL-'aggression' discriminated between the two groups.
  
  
  CONCLUSIONS
  The results suggest alterations in 5-HT functioning in CBCL-PBD-spectrum patients, and 'aggression' as a potential moderator variable to ADHD.
authors.affiliation: Department of Child and Adolescent Psychiatry and Psychotherapy, J.W. Goethe University, Frankfurt am Main, Germany. f.zepf@med.uni-frankfurt.de
authors.forename: F D
authors.initials: FD
authors.lastname: Zepf
authors.forename: L
authors.initials: L
authors.lastname: Wöckel
authors.forename: F
authors.initials: F
authors.lastname: Poustka
authors.forename: M
authors.initials: M
authors.lastname: Holtmann
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000523:psychology*; D001714:Bipolar Disorder / Q000523:psychology*; D002648:Child; D002653:Child Behavior Disorders / Q000523:psychology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D011930:Reaction Time; D012701:Serotonin / Q000502:physiology*; D014364:Tryptophan / Q000172:deficiency*
chemical_list: D012701:Serotonin; D014364:Tryptophan