Acute tryptophan depletion (ATD) is a technique used extensively to study the effect of low serotonin in the brain.[1] This experimental approach reduces the availability of tryptophan, an amino acid which serves as the precursor to serotonin.[1][2] The lack of mood-lowering effects after ATD in healthy subjects seems to contradict a direct causal relationship between acutely decreased serotonin levels and depression, although mood-lowering effects are observed in certain vulnerable individuals.[1]


  1. ^ a b c van Donkelaar EL, Blokland A, Ferrington L, Kelly PA, Steinbusch HW, Prickaerts J (July 2011). "Mechanism of acute tryptophan depletion: is it only serotonin?". Molecular Psychiatry. 16 (7): 695–713. doi:10.1038/mp.2011.9. PMID 21339754.
  2. ^ Young SN (September 2013). "Acute tryptophan depletion in humans: a review of theoretical, practical and ethical aspects". Journal of Psychiatry & Neuroscience. 38 (5): 294–305. doi:10.1503/jpn.120209. PMC 3756112. PMID 23428157.