Depression and HPA-axis dysregulation: A large cohort study

Abstract

There is a central belief that depression is associated with hyperactivity of the HPA-axis, resulting in higher cortisol levels. However, results are inconsistent. Our research aim was to determine whether there is an association between depression and cortisol levels in a large cohort, taking into account the use of psycho-active medication. Data are from 447 adults of the ongoing Netherlands Study of Depression and Anxiety. Participants were divided into 3 groups; 243 controls, 134 persons with major depressive disorder (MDD) without psycho-active medication and 100 with MDD with psycho-active medication. MDD was diagnosed using the CIDI interview and cortisol levels were measured in 7 saliva samples, covering a cortisol awakening response, basal evening level and a dexamethasone-suppression test. The 3 groups showed no significant differences in their cortisol awakening response. The mean value for the area under the curve with respect to the increase was 2.3 nmol/l*h for controls, 2.7 nmol/l*h for MDD without medication and 2.0 nmol/l*h for MDD with medication (p=0.77). In addition, basal evening levels and the ratio of morning cortisol before and after taking dexamethasone did not differ between groups. The findings did not change after adjustment for sociodemographics and health indicators. First results of this large cohort study indicate that depression is not associated with altered cortisol levels or difference in suppression after dexamethasone ingestion. Further analyses should explore the association between anxiety or trauma with cortisol values and whether there are certain subgroups of depressed patients with HPA-axis alterations.