title: The short (S) allele of the serotonin transporter polymorphism and acute tryptophan depletion both increase impulsivity in men.
abstract: Reduced serotonergic neurotransmission is implicated in impulsive behavior. We studied the triallelic system of the serotonin transporter gene linked polymorphic region (5-HTTLPR) and acute manipulation of serotonin together to further delineate the mechanisms by which serotonergic neurotransmission affects impulsivity. Fifty-two healthy participants (38 men and 14 women) underwent acute tryptophan depletion (ATD) or placebo in a randomized, double-blind, parallel group experiment. Impulsive response style was measured on two versions of the Continuous Performance Task (CPT), and calculated using signal detection theory. We observed a dose-dependent effect for the short (S') allele of the 5-HTTLPR on impulsive response style. Individuals who had the S'/S' genotype were more impulsive than individuals with the L/S' genotype. Participants with the L/S' genotype were more impulsive than those with the L/L genotype. ATD increased impulsivity in men, and decreased impulsivity in women. These data demonstrate for the first time that reduced serotonergic tone as a result of either 5-HTTLPR genotype, or experimental ATD, are both independently and additively, associated with elevated impulsive response style in Caucasian men.
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, West Haven, CT 06516, USA. espen.walderhaug@yale.edu
authors.forename: Espen
authors.initials: E
authors.lastname: Walderhaug
authors.forename: Aryeh Isaac
authors.initials: AI
authors.lastname: Herman
authors.forename: Andres
authors.initials: A
authors.lastname: Magnusson
authors.forename: Michael John
authors.initials: MJ
authors.lastname: Morgan
authors.forename: Nils Inge
authors.initials: NI
authors.lastname: Landrø
mesh_terms: D000328:Adult; D000483:Alleles; D004311:Double-Blind Method; D005260:Female; D005838:Genotype; D006801:Humans; D007175:Impulsive Behavior / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D012737:Sex Factors; D017603:Signal Detection, Psychological; D014364:Tryptophan / Q000172:deficiency; D044465:White People
chemical_list: D050486:Serotonin Plasma Membrane Transport Proteins; D014364:Tryptophan