New research by Mark Demitrack, MD, shows that the hypothalamic-pituitary-adrenal (HPA) axis function in CFS patients shows an abnormally low level of activity. This axis plays a significant role in the neuroendocrine process through which the body responds to and recovers from stress—including physical stress, emotional stress and the stress from fighting off an infection. Dr. Demitrack and his colleague in this study say this suggests that CFS is not caused by depression, because patients who have depression but not CFS do not have this HPA axis abnormality. However, fibromyalgia patients do have the same HPA axis abnormality that CFS patients have, which could indicate that CFS and FMS are related disorders.
Dr. Demitrack says it isn’t clear yet how the dysregulated HPA axis function develops, but his research shows that it seems to be due at least in part to an impaired central nervous system drive.
Demitrack, M.A., and Crofford, L.J., (1998). Evidence for and pathophysiologic implications of hypothalamic-pituitary-adrenal axis dysregulation in fibromyalgia and chronic fatigue syndrome. Annals of the New York Academy of Science, May 1, pp. 684–697.