HPA Axis Dysfunction, Hydrocortisone Treatment, and Chronic Fatigue Syndrome

Chronic fatigue syndrome (CFS) is characterized by hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis, largely assessed by peripheral measurements of cortisol secretion. Researchers measured 24-hour urinary free cortisol (UFC) levels as well as ACTH responses and cortisol responses to stress tests of HPA function in 37 drug-free CFS patients without comorbid psychiatric disorder and in 28 healthy controls.

The 2 groups showed no significant differences on the stress tests, although the CFS group showed a trend toward reduced cortisol responses to human corticotropin-releasing hormone (CRH) and D-fenfluramine. However, when the analysis was controlled for ACTH responses, the CFS group had significantly lower cortisol responses, com…