Using biological markers to inform a clinically meaningful treatment response

Combat veterans with posttraumatic stress disorder (PTSD) demonstrate less robust improvement following treatments than do civilians with PTSD. This paper discusses a theoretical model for evaluating treatment response based on the extent of change in biological markers of symptom severity or resilience between treatment initiation and termination. Such analysis permits a determination of biological change associated with the liberal criteria commonly used to determine treatment response in combat PTSD, and a comparison of this to the biological change associated with clinical response determined according to the conservative definition more appropriate to civilian PTSD. Interim data supporting the utility of this approach is presented based on preliminary analyses from our work in progress. We propose that future studies consider the unique consequences of combat trauma and develop treatments that incorporate the complex nature of the exposure and response characteristic of a veteran population.