Trauma-related but not PTSD-related increases in hair cortisol concentrations in military personnel

Dysregulated hypothalamic-pituitary-adrenal (HPA) axis functioning has been associated with posttraumatic stress disorder (PTSD). The current literature is inconsistent regarding this association, possibly due to confounding influences. Hair cortisol concentrations (HCC) allow for retrospective assessment of cumulative HPA axis secretion over several weeks and are considered a trait-like marker of HPA axis activity. Three groups of active and former German Armed Forces service members, comprising PTSD patients (n = 19), healthy controls with deployment-related trauma exposure (n = 10), and non-deployed healthy controls (n = 10) provided samples for HCC analysis. We observed significantly higher HCC in the PTSD and the deployed compared to the non-deployed group. HCC was neither significantly correlated with perceived chronic stress, nor with PTSD severity within patients. The results suggest a differential impact of trauma exposure on HPA axis activity and highlight the notion of cumulative, retrospective cortisol secretion as a psychobiological indicator of trauma exposure.