Cortisol reactivity in social anxiety disorder: A highly standardized and controlled study

Abstract

In order to understand the psychopathology of the social anxiety disorder (SAD) at the neuroendocrine level, standardized experimental studies on endocrine and physiological markers are necessary, especially since empirical data are still ambiguous. Hence, differences in both, the autonomic nervous system (ANS) and the endocrine stress responses (ACTH, salivary and plasma cortisol) were investigated in a particularly homogenous sample after a standardized stressor (Trier Social Stress Test). The sample consisted of n = 35 patients with SAD, age, and gender matched to n = 35 healthy controls (HC). In terms of the heart rate, the response pattern was comparable in both groups. Concerning ACTH, no significant group differences in the response pattern nor in the total output (AUC_G) were exhibited. Significant differences were noticeable only in the plasma cortisol response pattern with less total output (AUC_G) in patients suggesting a blunted response. The salivary cortisol response indicated comparable patterns between groups. However, the patients' total output (AUC_G) was significantly smaller relative to the controls. In sum, evidence for a hypo-responsiveness of the HPA-axis in SAD by means of blood cortisol was observed, with no differences in ACTH between the two groups. This reduced reactivity of the HPA-axis might be associated with an inability to elicit an adequate hormone release, possibly accompanied by an enhanced perception of the stress stimulus. This might be explained by an adaptation of the adrenocortical system due to prolonged repeated stress exposure such as social evaluation.

Keywords: ACTH; Laboratory stress induction; Plasma cortisol; Salivary; Social anxiety disorder; Trier social stress test (TSST).