The effect of deployment to a combat zone on testosterone levels and the association with the development of posttraumatic stress symptoms: A longitudinal prospective Dutch military cohort study

Objective: There is limited evidence on the association of the activity of HPG-axis with stress and symptoms of stress-related disorders. The aim of the current study was to assess the effect of deployment to a combat zone on plasma testosterone levels, and the possible association with the development of symptoms of posttraumatic stress disorder (PTSD). Methods: A total of 918 males were included in the study before deployment to a combat zone in Afghanistan. The effect of deployment on testosterone was longitudinally assessed; starting prior to deployment and follow-up assessments were preformed at 1 and 6 months after return. Furthermore, the association with PTSD symptoms reported at 1 and 2 years post-deployment was assessed. Results: Plasma testosterone levels were significantly increased after deployment compared with pre-deployment levels. Although no difference was found between individuals reporting high or low levels of PTSD symptoms, pre-deployment testosterone levels predicted the development of PTSD symptoms at 1 and 2 years post-deployment. Conclusion: This study provides evidence that not the alterations in testosterone levels shortly after deployment, but the pre-deployment testosterone levels are associated with PTSD symptoms, which is of value in the identification of biological vulnerability factors for the development of PTSD.