title: Acute yohimbine increases laboratory-measured impulsivity in normal subjects.
abstract: BACKGROUND
  State-dependent changes in impulsivity may be related to norepinephrine. To examine possible relationships between norepinephrine and acute changes in impulsivity, we measured effects of yohimbine, which increases norepinephrine release by blocking alpha-2 noradrenergic receptors, on laboratory-measured impulsivity in healthy subjects without psychiatric or substance-use disorders.
  
  
  METHODS
  Impulsivity was assessed using the Immediate and Delayed Memory Tasks (IMT-DMT), derived from the Continuous Performance Test, before and after placebo or two doses of yohimbine, given 4 days apart. Blood pressure was monitored, and psychiatric symptoms were measured using self-rated visual analog scales.
  
  
  RESULTS
  Yohimbine was associated with a dose-related increase in impulsive IMT commission errors, with an increase of > 50% relative to baseline at the higher dose. The activation factor of the Internal State Scale was increased at the same dose.
  
  
  CONCLUSIONS
  These results are consistent with increased impulsivity in normal subjects given yohimbine, possibly related to increased norepinephrine.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, Houston, Texas 77030, USA. Alan.C.Swann@uth.tmc.edu
authors.forename: Alan C
authors.initials: AC
authors.lastname: Swann
authors.forename: Daniel
authors.initials: D
authors.lastname: Birnbaum
authors.forename: Ashley A
authors.initials: AA
authors.lastname: Jagar
authors.forename: Donald M
authors.initials: DM
authors.lastname: Dougherty
authors.forename: F Gerard
authors.initials: FG
authors.lastname: Moeller
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000328:Adult; D001143:Arousal / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000139:chemically induced* / Q000523:psychology*; D008297:Male; D008568:Memory / Q000187:drug effects; D008570:Memory, Short-Term / Q000187:drug effects; D009638:Norepinephrine / Q000502:physiology; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology; D015016:Yohimbine / Q000494:pharmacology*
chemical_list: D000317:Adrenergic alpha-Antagonists; D015016:Yohimbine; D009638:Norepinephrine