Stress-induced increase in morning cortisol variance

Empirical evidence for the role of the hypothalamo-pituitary-adrenal axis in chronic stress is contradictory. Findings of enhanced cortisol concentrations conflict with hypocortisolism in chronic stress. Both, high and low cortisol levels, have been reported to go along with psychological and somatic complaints. To integrate conflicting empirical results and theoretical assumptions it is hypothesized, that (1) the cortisol distribution becomes broader under the influence of persisting stress. Because of the association between extreme cortisol values and stress related complaints it is supposed, that (2) stress related complaints will increase in prevalence in chronic stress. A high level of chronic stress was assured by recruiting a sample of nursing staff; a waiting list controlled cognitive-behavioral stress management intervention was implemented to vary stress systematically. As expected a high level of stress was accompanied by a broader morning cortisol distribution. After the intervention the distribution was less broad and corresponded with representative normative values. However, subjects grouped on basis of (extreme) cortisol values did not differ in the amount of stress, coping or psychophysiological complaints. The results suggest a stress-induced variation of basal cortisol concentrations. The assumption of specific complaints depending on cortisol status could not be confirmed. Copyright (C) 2004 John Wiley Sons, Ltd.