title: Effects of acute tryptophan depletion on three different types of behavioral impulsivity.
abstract: BACKGROUND
  While central nervous system serotonin has been implicated in a variety of problematic impulsive behaviors, biological manipulation of brain serotonin using acute tryptophan depletion for studying changes in impulsive behavior has received little attention.
  
  
  METHODS
  Using identical treatment conditions, we examined the effects of reduced serotonin synthesis for each of three matched groups using acute tryptophan depletion. Thirty healthy men and women (ages 18-45) were assigned to perform one of three tasks assessing different types of behavioral impulsivity: response initiation, response inhibition, and consequence sensitivity (N = 90). Participants completed two experimental days during which each consumed either a tryptophan-depletion or balanced-placebo amino-acid formulation and completed 5 sessions of their respective tasks at 0.25 h before and 1.5, 4.0, 5.0, and 6.0 h after beverage consumption.
  
  
  RESULTS
  During peak effectiveness (5.0 h to 6.0 h following amino-acid consumption), depletion produced selective differences dependent on the type of impulsivity being tested. Specifically, relative to baseline testing (pre-depletion), response initiation impulsivity was significantly increased during the peak effects of depletion. And, when compared to placebo control, both response initiation and consequence sensitivity impulsivity were increased during the peak effects of depletion.
  
  
  CONCLUSIONS
  Though response initiation and consequence sensitivity impulsivity were affected by tryptophan depletion, response inhibition impulsivity was not, suggesting that other biological processes may underlie this specific component of impulsivity. Future research in other populations or using different pharmacological agents is warranted to further examine the biological processes underlying these components of impulsivity.
authors.affiliation: Neurobehavioral Research Laboratory and Clinic, Department of Psychiatry, The University of Texas Health Science Center at San Antonio, TX.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Dougherty
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Richard
authors.forename: Lisa M
authors.initials: LM
authors.lastname: James
authors.forename: Charles W
authors.initials: CW
authors.lastname: Mathias
references.citation: Psychopharmacology (Berl). 1989;98(4):508-11
references.pmid: 2505291
references.citation: PLoS One. 2007 Dec 19;2(12):e1333
references.pmid: 18091999
references.citation: Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2008 Jul;33(7):571-5
references.pmid: 18667767
references.citation: Am J Psychiatry. 1982 Jun;139(6):741-6
references.pmid: 6177256
references.citation: Alcohol Clin Exp Res. 2000 Nov;24(11):1702-11
references.pmid: 11104118
references.citation: Neuropsychopharmacology. 1998 Oct;19(4):333-41
references.pmid: 9718596
references.citation: Clin Psychol Rev. 2006 Aug;26(4):379-95
references.pmid: 16504359
references.citation: Ann N Y Acad Sci. 1986;487:243-55
references.pmid: 2436537
references.citation: Behav Res Methods Instrum Comput. 2002 Aug;34(3):391-8
references.pmid: 12395555
references.citation: Psychopharmacology (Berl). 2007 Jul;193(1):137-50
references.pmid: 17377773
references.citation: Compr Psychiatry. 2009 Jul-Aug;50(4):315-21
references.pmid: 19486729
references.citation: Biol Psychiatry. 2007 Sep 15;62(6):593-9
references.pmid: 17544379
references.citation: Alcohol. 1985 May-Jun;2(3):415-8
references.pmid: 2411275
references.citation: J Child Psychol Psychiatry. 2003 Nov;44(8):1145-57
references.pmid: 14626456
references.citation: Psychopharmacology (Berl). 2002 Aug;163(1):42-53
references.pmid: 12185399
references.citation: Arch Gen Psychiatry. 1994 Jan;51(1):28-33
references.pmid: 7506516
references.citation: Psychiatry Res. 1983 Dec;10(4):253-61
references.pmid: 6199807
references.citation: Arch Gen Psychiatry. 1991 May;48(5):437-41
references.pmid: 1708656
references.citation: Psychopharmacology (Berl). 1985;87(2):173-7
references.pmid: 3931142
references.citation: Drug Alcohol Depend. 2008 Jul 1;96(1-2):111-20
references.pmid: 18378098
references.citation: Psychopharmacology (Berl). 2002 Dec;164(4):385-91
references.pmid: 12457268
references.citation: Physiol Rev. 1983 Apr;63(2):484-546
references.pmid: 6132421
references.citation: Arch Gen Psychiatry. 1994 Jan;51(1):20-7
references.pmid: 7506515
references.citation: Prog Neuropsychopharmacol Biol Psychiatry. 1989;13(3-4):505-11
references.pmid: 2473488
references.citation: Arch Gen Psychiatry. 1979 Feb;36(2):224-7
references.pmid: 420544
references.citation: Am J Psychiatry. 1999 Nov;156(11):1771-9
references.pmid: 10553742
references.citation: Psychopharmacology (Berl). 2009 Mar;203(1):53-61
references.pmid: 18946662
references.citation: Int J Tryptophan Res. 2009 Mar 23;2:45-60
references.pmid: 20651948
references.citation: Psychopharmacology (Berl). 1995 Mar;118(1):72-81
references.pmid: 7597125
references.citation: Drug Alcohol Depend. 2004 Dec 7;76 Suppl:S93-S105
references.pmid: 15555820
references.citation: Neuropsychopharmacology. 2002 May;26(5):660-71
references.pmid: 11927191
references.citation: Psychopharmacology (Berl). 2008 Jun;198(3):431-45
references.pmid: 18452034
references.citation: Addict Disord Their Treat. 2009 Jun 1;8(2):61-73
references.pmid: 20535237
references.citation: Biol Psychiatry. 2005 Jun 1;57(11):1285-92
references.pmid: 15950000
references.citation: Behav Sci Law. 2008;26(6):691-707
references.pmid: 19039792
references.citation: Psychopharmacology (Berl). 1999 Feb;142(1):24-30
references.pmid: 10102779
references.citation: J Psychiatr Res. 2009 Aug;43(12):1036-48
references.pmid: 19232640
references.citation: Arch Gen Psychiatry. 1976 Oct;33(10):1193-7
references.pmid: 971028
references.citation: Exp Clin Psychopharmacol. 2007 Jun;15(3):264-71
references.pmid: 17563213
references.citation: Proc Natl Acad Sci U S A. 1997 May 13;94(10):5308-13
references.pmid: 9144233
references.citation: Exp Clin Psychopharmacol. 2009 Oct;17(5):302-11
references.pmid: 19803629
references.citation: Drug Alcohol Depend. 2009 Nov 1;105(1-2):89-96
references.pmid: 19615829
references.citation: J Psychiatr Res. 2009 Aug;43(12):1057-63
references.pmid: 19345957
references.citation: Hum Psychopharmacol. 2008 Jan;23(1):43-51
references.pmid: 17926336
references.citation: J Affect Disord. 2009 Jul;116(1-2):30-6
references.pmid: 19038460
references.citation: Behav Brain Res. 2002 Nov 15;136(2):349-57
references.pmid: 12429396
references.citation: J Psychiatry Neurosci. 1993 Nov;18(5):235-44
references.pmid: 8297922
references.citation: Pharmacol Biochem Behav. 2002 Apr;71(4):857-65
references.pmid: 11888576
references.citation: J Clin Psychol. 1995 Nov;51(6):768-74
references.pmid: 8778124
references.citation: Med Hypotheses. 1987 Aug;23(4):353-61
references.pmid: 2443817
references.citation: J Neural Transm. 1981;50(2-4):89-101
references.pmid: 6165805
references.citation: Drug Alcohol Depend. 2004 Dec 7;76 Suppl:S3-9
references.pmid: 15555814
references.citation: Behav Res Methods. 2005 Feb;37(1):82-90
references.pmid: 16097347
references.citation: Aust N Z J Psychiatry. 2005 Jul;39(7):558-64
references.pmid: 15996136
references.citation: Am J Psychiatry. 2001 Nov;158(11):1783-93
references.pmid: 11691682
references.citation: Adv Exp Med Biol. 1996;398:75-82
references.pmid: 8906244
references.citation: Psychiatry Res. 2001 Mar 25;101(2):195-7
references.pmid: 11286822
references.citation: Pharmacopsychiatry. 1995 Oct;28 Suppl 2:93-7
references.pmid: 8614707
references.citation: Psychopharmacology (Berl). 1981;75(4):339-45
references.pmid: 6803276
references.citation: J Neurosci. 2008 Apr 23;28(17):4528-32
references.pmid: 18434531
references.citation: Psychopharmacology (Berl). 2009 Aug;205(3):349-68
references.pmid: 19404614
references.citation: Psychiatr Clin North Am. 2000 Mar;23(1):11-25
references.pmid: 10729928