Acute tryptophan depletion. Part II: clinical effects and implications

Aust N Z J Psychiatry. 2005 Jul;39(7):565-74. doi: 10.1080/j.1440-1614.2005.01628.x.


Objective: This is the second of two articles reviewing the modern dietary technique of acute tryptophan depletion (ATD), a method of transiently reducing central serotonin levels in both healthy volunteers and clinical populations. This article details the clinical studies to date and discusses the implications of this research methodology.

Method: The authors present a review of clinical ATD studies collated from a MEDLINE search, unpublished communications and the authors' considerable experience with this paradigm.

Results: Following from the initial use of ATD in subjects with depressive illness, studies of anxiety disorders and other psychiatric illnesses have been reported. Sleep, aggressive and cognitive effects are also active areas of research and are reviewed here.

Conclusions: Acute tryptophan depletion remains a useful psychiatric research tool. The findings from the clinical studies reviewed here are summarized and implications for future research detailed.

Publication types

  • Review

MeSH terms

  • Alleles
  • Alzheimer Disease / metabolism
  • Autistic Disorder / metabolism
  • Bipolar Disorder / metabolism
  • Cognitive Behavioral Therapy / methods
  • Depressive Disorder, Major / genetics
  • Depressive Disorder, Major / metabolism*
  • Depressive Disorder, Major / therapy
  • Disruptive, Impulse Control, and Conduct Disorders / metabolism
  • Feeding and Eating Disorders / metabolism
  • Female
  • Humans
  • Hydroxyindoleacetic Acid / metabolism
  • Monoamine Oxidase Inhibitors / pharmacology
  • Monoamine Oxidase Inhibitors / therapeutic use
  • Premenstrual Syndrome / metabolism
  • Promoter Regions, Genetic / genetics
  • Schizophrenia / metabolism
  • Selective Serotonin Reuptake Inhibitors / pharmacology
  • Selective Serotonin Reuptake Inhibitors / therapeutic use
  • Serotonin / genetics
  • Serotonin / metabolism*
  • Serotonin Plasma Membrane Transport Proteins / genetics
  • Sleep Wake Disorders / diagnosis
  • Sleep Wake Disorders / metabolism
  • Sleep, REM / physiology
  • Surveys and Questionnaires
  • Tryptophan / deficiency*
  • Tryptophan / genetics
  • Tryptophan / metabolism


  • Monoamine Oxidase Inhibitors
  • Serotonin Plasma Membrane Transport Proteins
  • Serotonin Uptake Inhibitors
  • Serotonin
  • Hydroxyindoleacetic Acid
  • Tryptophan