US Army: Estrogen Receptors' Involvement in Post-Traumatic Stress Syndrome

Post-Traumatic Stress Disorder (PTSD) is a complex anxiety-related disorder that occurs in response to a traumatic or life-threatening event, such as military combat, exposure to personal violence, or exposure to car accidents. The war on terror being fought on two fronts, Afghanistan and Iraq, is the most sustained combat operations since the Vietnam War. Among military service members, the potential for exposure to trauma and development of PTSD increases markedly during times of war. In a recent comprehensive study, the estimated risk for PTSD from service in the Iraq war is 18% and the estimated risk for PTSD in the Afghanistan mission is 11% (Hoge et al., 2004).

Currently, PTSD is the most frequently cited psychiatric disorder to justify veteran's claims for disability benefits (Murdoch, 2003). The disorder is costly. In 1998, the Veterans Benefits Administration paid an estimated $23.2 million in compensation to veterans suffering from PTSD. The social and personal costs to PTSD patients and their families are incalculable. While current treatments help some patients with PTSD, they do not help all patients. Furthermore, not only is the underlying cause not understood, no preventative treatments are available to those likely to be exposed to trauma such as military service members.

Preliminary data, using an animal model in our laboratory, suggest that estrogen may be useful to both prevent and treat PTSD. The administration of estradiol prevented the development of PTSD-related behaviors (e.g. exaggerated startle responses). Importantly, the results implicated one of the two known estrogen receptors (ER), ER╬▓, to be critical in mediating these responses. The long-term goal of our laboratory is to identify and develop new targets for novel countermeasures for PTSD among military personnel and civilians likely to be exposed to trauma. The specific aims of this research are to determine which estrogen receptor agonist can be an effective preventative treatment for PTSD-related behaviors. The proposed work will expand upon these initial findings by linking behavioral changes with estrogen receptor changes in the central nervous system (CNS) before and after trauma exposure. We will use a well-established animal model of PTSD. This work will begin to elucidate estrogen's protective effects in the CNS prior to traumatic events.

This research project is relevant to military nursing research because an innovative treatment based on these results will dramatically improve soldier's lives. Information obtained from this dynamic interdisciplinary approach is critical since it will contribute to further development of preventative strategies for the debilitating effects of PTSD. This project will increase the knowledge base of basic medical science, which is vital for the proper care of our combat and civilian patients under the care of Nurse Corps officers.