title: Platelet MAO activity and the 5-HTT gene promoter polymorphism are associated with impulsivity and cognitive style in visual information processing.
abstract: BACKGROUND
  Low capacity of the central serotonergic system has been associated with impulsive behaviour. Both low platelet monoamine oxidase (MAO) activity and the short (S) allele of the serotonin transporter gene promoter region polymorphism (5-HTTLPR) are proposed to be markers of less efficient serotonergic functioning.
  
  
  OBJECTIVE
  The effect of the two markers for serotonin system efficiency on performance in a visual comparison task (VCT) and self-reported impulsiveness (Barratt Impulsiveness Scale, BIS-11) were investigated in healthy adolescents participating in the Estonian Children Personality Behaviour and Health Study. Possible confounding effect of general cognitive abilities on the performance in VCT was controlled for.
  
  
  RESULTS
  Low platelet MAO activity and carrying of the S allele of 5-HTTLPR were both associated with higher error-rate and more impulsive performance in VCT. Platelet MAO activity and 5-HTTLPR S allele had a significant interactive effect on self-reported impulsivity (BIS-11). The effect of platelet MAO activity on both self-reported and performance impulsivity was significant only in the S allele carriers. The effect of 5-HTTLPR S allele on impulsive performance remained significant after controlling for general cognitive abilities.
  
  
  CONCLUSIONS
  The two markers of lower serotonergic capacity, 5-HTTLPR S allele and low platelet MAO activity, have a similar and partly synergistic influence on self-reported as well as performance measures of impulsivity.
authors.affiliation: Department of Psychology, University of Tartu, Tiigi 78, 50410, Tartu, Estonia.
authors.forename: Marika
authors.initials: M
authors.lastname: Paaver
authors.forename: Niklas
authors.initials: N
authors.lastname: Nordquist
authors.forename: Jüri
authors.initials: J
authors.lastname: Parik
authors.forename: Maarike
authors.initials: M
authors.lastname: Harro
authors.forename: Lars
authors.initials: L
authors.lastname: Oreland
authors.forename: Jaanus
authors.initials: J
authors.lastname: Harro
mesh_terms: D000293:Adolescent; D000483:Alleles; D001792:Blood Platelets / Q000201:enzymology; D003071:Cognition / Q000502:physiology*; D005260:Female; D005838:Genotype; D006801:Humans; D007175:Impulsive Behavior / Q000201:enzymology / Q000235:genetics / Q000523:psychology*; D008297:Male; D008606:Mental Processes / Q000502:physiology; D008995:Monoamine Oxidase / Q000378:metabolism*; D010364:Pattern Recognition, Visual / Q000502:physiology; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D011581:Psychological Tests; D011930:Reaction Time / Q000502:physiology; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D008995:Monoamine Oxidase