Sympathetic and hypothalamic‐pituitary‐adrenal asymmetry in generalized anxiety disorder
Published online on March 02, 2016
Abstract
Physiologic investigations of generalized anxiety disorder (GAD) have skewed toward assessment of the autonomic nervous system, largely neglecting hypothalamic‐pituitary‐adrenal (HPA) axis variables. Although these systems coordinate—suggesting a degree of symmetry—to promote adaptive functioning, most studies opt to monitor either one system or the other. Using a ratio of salivary alpha‐amylase (sAA) over salivary cortisol, the present study examined symmetry between the sympathetic nervous system (SNS) and HPA axis in individuals with GAD (n = 71) and healthy controls (n = 37). Compared to healthy controls, individuals with GAD exhibited greater baseline ratios of sAA/cortisol and smaller ratios of sAA/cortisol following a mental arithmetic challenge. We propose that the present study provides evidence for SNS‐HPA asymmetry in GAD. Further, these results suggest that increased SNS suppression in GAD may be partially mediated by cortisol activity.