title: Effects of acute tryptophan depletion on mood and suicidal ideation in bipolar patients symptomatically stable on lithium.
abstract: BACKGROUND
  Previous studies suggest that brain serotonin neurotransmission may mediate the actions of lithium carbonate. Acute tryptophan depletion reduces brain serotonin and allows the study of this neurotransmitter in patient groups.
  
  
  OBJECTIVE
  To examine the effects of acute tryptophan depletion on mood and suicidal ideation in bipolar patients who were symptomatically stable on lithium.
  
  
  METHODS
  Nineteen subjects satisfying DSM-IV criteria for bipolar I disorder participated in a within-subject, double-blind, placebo-controlled random-order crossover study. Symptoms were evaluated following acute tryptophan depletion, which was induced by a 100 g amino acid drink following an overnight fast.
  
  
  RESULTS
  Plasma tryptophan fell significantly after the depleting drink, but not after the control drink (P < 0.05, paired t-test, mean reduction 83%). No significant changes in mood or suicidality scores were recorded after acute tryptophan depletion.
  
  
  CONCLUSIONS
  Acute tryptophan depletion does not reverse lithium's effects on mood and suicidality in bipolar disorder.
authors.affiliation: Department of Psychiatry, Hadrian Clinic, Newcastle General Hospital, Newcastle upon Tyne, UK.
authors.forename: J H
authors.initials: JH
authors.lastname: Hughes
authors.forename: F
authors.initials: F
authors.lastname: Dunne
authors.forename: A H
authors.initials: AH
authors.lastname: Young
mesh_terms: D000328:Adult; D000339:Affect / Q000187:drug effects* / Q000502:physiology; D018692:Antimanic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy / Q000378:metabolism* / Q000523:psychology; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008094:Lithium / Q000097:blood; D016651:Lithium Carbonate / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D012701:Serotonin / Q000502:physiology; D013405:Suicide / Q000523:psychology*; D014364:Tryptophan / Q000097:blood / Q000172:deficiency*
chemical_list: D018692:Antimanic Agents; D016651:Lithium Carbonate; D012701:Serotonin; D014364:Tryptophan; D008094:Lithium