title: Cognition following acute tryptophan depletion: difference between first-degree relatives of bipolar disorder patients and matched healthy control volunteers.
abstract: BACKGROUND
  Serotonergic circuits have been proposed to mediate cognitive processes, particularly learning and memory. Cognitive impairment is often seen in bipolar disorders in relation to a possible lowered serotonergic turnover.
  
  
  METHODS
  We investigated the effects of acute tryptophan depletion (ATD) on cognitive performance in healthy first-degree relatives of bipolar patients (FH) (N= 30) and matched controls (N= 15) in a placebo-controlled, double-blind cross-over design. Performance on planning, memory and attention tasks were assessed at baseline and 5 h after ATD.
  
  
  RESULTS
  Following ATD, speed of information processing on the planning task was impaired in the FH group but not in the control group. FH subjects with a bipolar disorder type I relative (FH I) showed impairments in planning and memory, independent of ATD. In all subjects, ATD impaired long-term memory performance and speed of information processing. ATD did not affect short-term memory and focused and divided attention.
  
  
  CONCLUSIONS
  The results suggest serotonergic vulnerability affecting frontal lobe areas in FH subjects, indicated by impaired planning. Biological vulnerability in FH I subjects is reflected in impaired planning and memory performance. In conclusion, the cognitive dysfunctions in FH subjects indicate an endophenotype constituting a possible biological marker in bipolar psychopathology. Serotonin appears to be involved in speed of information processing, verbal and visual memory and learning processes.
authors: Brain and Behaviour Institute, Department of Psychiatry and Neuropsychology, Universiteit Maastricht, The Netherlands.
authors: S
authors: S
authors: Sobczak
authors: W J
authors: WJ
authors: Riedel
authors: I
authors: I
authors: Booij
authors: M
authors: M
authors: Aan Het Rot
authors: N E P
authors: NE
authors: Deutz
authors: A
authors: A
authors: Honig
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage; D001714:Bipolar Disorder / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D004311:Double-Blind Method; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012306:Risk; D012701:Serotonin / Q000502:physiology*; D014364:Tryptophan / Q000172:deficiency*
chemical_list: D000596:Amino Acids; D012701:Serotonin; D014364:Tryptophan