Impact of experimentally induced serotonin deficiency by tryptophan depletion on saliva cortisol concentrations.
BACKGROUND
Tryptophan depletion (TD) has been shown to induce a transient mood-lowering effect in psychiatric patients and susceptible healthy subjects. We investigated the effects of TD on cortisol secretion in psychiatric patients and healthy subjects based on the hypothesis that the potential mood-lowering effects may be associated with increased activity of the hypothalamic-pituitary-adrenal axis, thus leading to a rise of cortisol secretion.


METHODS
After TD at 18.00 h, salivary cortisol was sampled in the evening and on the following morning. The first study was a randomized, placebo-controlled, crossover study in healthy subjects. Two further open trials in patients with obsessive-compulsive disorder (OCD) and primary insomnia compared the effects of TD on cortisol with baseline conditions.


RESULTS
In healthy subjects, TD significantly diminished cortisol the next morning compared with placebo. In OCD patients and primary insomniacs, cortisol the morning after TD was lowered compared with baseline. Evening cortisol was not affected by TD in any of the groups.


CONCLUSIONS
Contrary to expectation, TD led to a comparable decrease of morning cortisol in all groups investigated. However, these findings are consistent with former studies analyzing the impact of antiserotonergic drugs on cortisol secretion. The results underline that the antiserotonergic effects caused by TD may influence cortisol secretion.
Vielhaber
K
K
Department of Psychiatry and Psychotherapy, University Hospital of Freiburg, Germany. Ulrich_Voderholzer@psyallg.uki.uni-freiburg.de
Riemann
D
D
Feige
B
B
Kuelz
A
A
Kirschbaum
C
C
Voderholzer
U
U
D000328:Adult; D018592:Cross-Over Studies; D003866:Depressive Disorder / Q000097:blood / Q000503:physiopathology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000097:blood / Q000503:physiopathology; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D011594:Psychometrics; D012463:Saliva / Q000737:chemistry*; D012701:Serotonin / Q000172:deficiency*; D007319:Sleep Initiation and Maintenance Disorders / Q000097:blood / Q000503:physiopathology; D014364:Tryptophan / Q000172:deficiency*
D012701:Serotonin; D014364:Tryptophan; D006854:Hydrocortisone