SEROTONERGIC VULNERABILITY IN AFFECTIVE-DISORDER - A STUDY OF THE TRYPTOPHAN DEPLETION TEST AND RELATIONSHIPS BETWEEN PERIPHERAL AND CENTRAL SEROTONIN INDEXES IN CITALOPRAM-RESPONDERS

A double-blind study of the tryptophan depletion (TD) challenge was pe rformed on a sample consisting of 20 patients with a major depressive disorder in clinical remission after citalopram treatment. TD was indu ced by the intake of 43 g of an amino acid mixture containing the five large neutral amino acids. The control group received the same mixtur e, to which 2.3 g tryptophan had been added. Five of the 12 challenged patients showed a worsening of depressive symptoms during the day of the test. In contrast, there was no mood alteration in the eight contr ol patients. Baseline cortisol levels were significantly higher in res ponders to TD compared to those in non-responders and controls. Platel et serotonin-receptor function and plasma prolactin levels were correl ated. There was a significant positive correlation in the baseline dat a between rated mood state and plasma cortisol and a significant inver se correlation between related mood state and plasma tryptophan concen tration. Thus low mood appeared to be associated with low serotonin pr ecursor availability as well as with high cortisol levels.