Reduced reactivity and enhanced negative feedback sensitivity of the hypothalamus-pituitary-adrenal axis in chronic whiplash-associated disorder.

Dysregulations of the hypothalamus-pituitary-adrenal (HPA) axis have been discussed as a physiological substrate of chronic pain and fatigue. The aim of the study was to investigate possible dysregulations of the HPA axis in chronic whiplash-associated disorder (WAD). In 20 patients with chronic WAD and 20 healthy controls, awakening cortisol responses as well as a short circadian free cortisol profile were assessed before and after administration of 0.