BACKGROUND: Rapid and transient depletion of tryptophan (TRP) causes a brief depressive relapse in most patients successfully treated with and taking selective serotonin reuptake inhibitors, but little change in drug-free, symptomatic depressed patients. This study investigates the effects of TRP depletion in drug-free subjects in clinical remission from a prior major depressive episode (MDE). METHODS:Twelve subjects with a prior MDE, currently in clinical remission and drug-free for at least 3 months (patients), and 12 healthy subjects without personal or family history of Axis I disorder (controls), received TRP depletion. The study was conducted in a double-blind, controlled [full (102-g) and quarter-strength (25 g) 15-amino acid drinks], crossover fashion. Behavioral ratings and plasma TRP levels were obtained prior to, during, and after testing. RESULTS: All subjects experienced significant depletion of plasma TRP on both test-drinks, showing a significant dose-response relation. Healthy control subjects had minimal mood changes, but patients had a depressive response of greater magnitude. CONCLUSIONS: In the context of prior TRP depletion studies with antidepressant-treated, and drug-free symptomatic depressed patients, these results suggest that depression may be caused not by an abnormality of 5-HT function, but by dysfunction of other systems or brain regions modulated by 5-HT.
RCT Entities:
BACKGROUND: Rapid and transient depletion of tryptophan (TRP) causes a brief depressive relapse in most patients successfully treated with and taking selective serotonin reuptake inhibitors, but little change in drug-free, symptomatic depressedpatients. This study investigates the effects of TRP depletion in drug-free subjects in clinical remission from a prior major depressive episode (MDE). METHODS: Twelve subjects with a prior MDE, currently in clinical remission and drug-free for at least 3 months (patients), and 12 healthy subjects without personal or family history of Axis I disorder (controls), received TRP depletion. The study was conducted in a double-blind, controlled [full (102-g) and quarter-strength (25 g) 15-amino acid drinks], crossover fashion. Behavioral ratings and plasma TRP levels were obtained prior to, during, and after testing. RESULTS: All subjects experienced significant depletion of plasma TRP on both test-drinks, showing a significant dose-response relation. Healthy control subjects had minimal mood changes, but patients had a depressive response of greater magnitude. CONCLUSIONS: In the context of prior TRP depletion studies with antidepressant-treated, and drug-free symptomatic depressedpatients, these results suggest that depression may be caused not by an abnormality of 5-HT function, but by dysfunction of other systems or brain regions modulated by 5-HT.
Authors: Nassima Ait-Daoud; John D Roache; Michael A Dawes; Lei Liu; Xin-Qun Wang; Martin A Javors; Chamindi Seneviratne; Bankole A Johnson Journal: Alcohol Clin Exp Res Date: 2009-05-04 Impact factor: 3.455
Authors: Francisco A Moreno; Damian Parkinson; Craig Palmer; Wm Lesley Castro; John Misiaszek; Aram El Khoury; Aleksander A Mathé; Ron Wright; Pedro L Delgado Journal: Eur Neuropsychopharmacol Date: 2010-01 Impact factor: 4.600
Authors: John J B Allen; Katherine M McKnight; Francisco A Moreno; Heath A Demaree; Pedro L Delgado Journal: J Affect Disord Date: 2008-09-18 Impact factor: 4.839