The citalopram challenge test in patients with major depression and in healthy controls

Neuroendocrine challenge tests in depressed patients have revealed a blunte d hormonal reaction to serotonergic stimuli. In the present study, citalopr am was chosen as the serotonergic agent for neuroendocrine stimulation. Com pared to earlier challenge agents, citalopram has the advantage of serotone rgic selectivity, its application is well tolerated and the possibility of intravenous application reduces pharmacokinetic interference. Sixteen patie nts suffering from an acute episode of major depression and 16 healthy cont rols underwent the stimulation procedure with 20 mg of citalopram and place bo. Whereas significant differences in the secretion of prolactin and corti sol between citalopram and placebo challenge were observed in the control g roup, no differences were found in the group of depressed patients. Compari son of depressed patients and controls showed a significantly blunted prola ctin secretion in patients. Differences in cortisol secretion following ser otonergic stimulation with citalopram did not become significant. The stimu lation procedure was well tolerated in all subjects, although a higher numb er of side effects was observed in the control group. The amount of side ef fects did not correlate with the hormone responses. These results are in li ne with the hypothesis of serotonergic hypofunction in depressed patients. In conclusion, the 20-mg citalopram challenge test is thought to be a promi sing tool for further investigation of serotonergic function in psychiatric illness. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.