Anxiety disorders and salivary cortisol levels in older adults: a population-based study

CONTEXT The hypothalamic-pituitary-adrenal (HPA) axis is one of the body's main systems that controls response to stress. It acts through the hormone cortisol. While the dysregulation of cortisol has been associated with anxiety disorders, the evidence is inconsistent. Moreover, only a few small studies have assessed this relationship in older adults. OBJECTIVE To determine whether in adults aged 65 years and over there is a difference in daily cortisol pattern between those with and without an anxiety disorder. METHODS The study population comprised 1788 older adults from a population-based cohort. The Munich version of the Composite International Diagnostic Interview was used to diagnose anxiety disorders (generalized anxiety disorder, social phobia, specific phobia, agoraphobia and panic disorder). The cortisol awakening response and total cortisol secretion over the day were calculated from cortisol levels in four saliva samples taken over the course of one day (at awakening, 30min after awakening, at 1700h, at bedtime). RESULTS Older adults with an anxiety disorder (n=145, median duration since first symptoms 41 years) had a lower cortisol awakening response (p=0.02) than those without such a disorder (n=1643). This association was most prominent in those with generalized anxiety disorder (p=0.008), but was not associated with the extent of chronicity of anxiety disorders. CONCLUSION Older adults from the general population with long-lasting anxiety disorders had a lower cortisol awakening response than those without. This is consistent with the notion that chronic anxiety may result in downregulation of HPA-axis activity. Longitudinal studies are needed to confirm this mechanism.