title: Acute tryptophan depletion as a model of depressive relapse: behavioural specificity and ethical considerations.
abstract: BACKGROUND
  Acute tryptophan depletion transiently induces symptoms in those with remitted depression. The behavioural specificity is uncertain, however. Recently, symptom provocation studies have become controversial, particularly in the USA.
  
  
  OBJECTIVE
  To assess the specificity of acute tryptophan depletion. To investigate systematically the subjective experiences of those taking part in a symptom provocation study.
  
  
  METHODS
  Twenty individuals with remitted depression underwent acute tryptophan depletion in a double-blind, crossover trial. Psychiatric symptoms and self-schemata relevant to depression were assessed. The quality of the informed consent procedure and subjective experiences were also evaluated.
  
  
  RESULTS
  Acute tryptophan depletion induced a specific depressive response. The effects were more pronounced in females than in males. Participants were quite satisfied with the informed consent procedure. They had understood that this was a fundamental research project and personal benefits were not expected. However, some participants still found it a positive experience.
  
  
  CONCLUSIONS
  Acute tryptophan depletion is a suitable model of vulnerability to depression, from both a scientific and an ethical perspective.
authors.affiliation: Department of Psychology, Leiden University, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands.
authors.forename: Linda
authors.initials: L
authors.lastname: Booij
authors.forename: A J Willem
authors.initials: AJ
authors.lastname: van der Does
authors.forename: P M Judith
authors.initials: PM
authors.lastname: Haffmans
authors.forename: Philip
authors.initials: P
authors.lastname: Spinhoven
authors.forename: Richard J
authors.initials: RJ
authors.lastname: McNally
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage / Q000009:adverse effects; D018592:Cross-Over Studies; D003866:Depressive Disorder / Q000097:blood / Q000188:drug therapy* / Q000523:psychology; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007258:Informed Consent / Q000941:ethics; D008297:Male; D008875:Middle Aged; D010353:Patient Education as Topic / Q000941:ethics / Q000592:standards; D011569:Psychiatric Status Rating Scales; D012647:Self-Assessment; D012737:Sex Factors; D016896:Treatment Outcome; D014364:Tryptophan / Q000097:blood / Q000172:deficiency*
chemical_list: D000596:Amino Acids; D014364:Tryptophan