Bouncing back : trauma and the HPA-axis in healthy adults

Abstract

Dysregulation of the hypothalamic-pituitary-adrenal (HPA)-axis is hypothesized to underlie stress-related psychiatric disorders such as the posttraumatic stress disorder (PTSD). Some studies have reported HPA-axis dysregulation in trauma-exposed adults in the absence of psychiatric morbidity. In this dissertation we set out to unravel part of the mechanism that underlies the complex relation between trauma exposure, stress regulation, and psychopathology. Mentally healthy trauma-exposed subjects were compared with non-trauma-exposed healthy controls. To distinguish between the potential effects of childhood trauma as opposed to adulthood trauma, we included women exposed to childhood trauma as well as men who were exposed to trauma during adulthood. Basal HPA-axis functioning was assessed with salivary cortisol samples. HPA-axis reactivity was assessed with the dexamethasone/corticotropin-releasing hormone (Dex/CRH) test. The results show that childhood trauma exposure is associated with an attenuated cortisol response after the Dex/CRH challenge test in women. In contrast, trauma exposure during adulthood was not associated with alterations in HPA-axis regulation after the Dex/CRH test. Neither childhood trauma nor adulthood trauma were associated with basal HPA-axis functioning. Childhood trauma rather than adulthood trauma may chronically affect HPA-axis functioning. Since the association between adulthood trauma and resilience to psychopathology cannot be explained by HPA-axis functioning alone, other factors must play a role.