Hair cortisol concentrations to picture the dysregulation of the hypothalamic-pituitary-adrenocortical axis in panic disorder.

Panic attacks are characterized by intense feelings of uncontrollable threat and induce experiences of intense stress. As one of the major physiological stress systems of the body, the hypothalamic-pituitary-adrenocortical axis (HPA) may be a key to our understanding of a biological basis of this anxiety disorder. While recent studies have found evidence for short-term HPA changes in panic disorder with flattened cortisol responses to stimulation, no data have been available on tonic, i.e., long-term HPA activity in these patients. The current study therefore investigated the cumulative cortisol incorporation in hair over the period of three months in patients with panic disorder (n = 45) and healthy individuals (n = 45). Results showed higher hair cortisol concentration in patients with panic disorder compared to healthy controls. The duration and the severity of the disorder was unrelated to hair cortisol concentrations. In subsample analyses, patients with panic disorder and comorbid depression showed no significant differences in hair cortisol concentration compared to patients with pure panic disorder. The present findings do not support to the notion that a hypoactive HPA axis may be an important biological feature of patients suffering from panic disorder. Future studies will have to show in a large sample whether a changed HPA axis reactivity is present and causally related to the development and course of the disorder.