Biomarkers for PTSD

PI: Charles R. Marmar, MD,  Dept. of Psychiatry, NYU School of Medicine

It is estimated that 10% to 20% of warfighters who have served in Iraq and Afghanistan have PTSD.  An important limitation of these studies is the reliance on self-report screening measures and clinical interviews to make the diagnosis of PTSD.  These methods are subject to a number of biases, including underreporting of PTSD symptoms because of stigma of mental illness and concerns about adverse effects on careers, and exaggeration of symptoms in those seeking compensation for service- connected disability. Development of biomarkers of PTSD is critical for DOD and VA as objective indicators of PTSD for use in post-deployment medical screening, treatment selection, treatment outcome monitoring, disability evaluations, and for informing novel targets for treatment development.  Additionally, biomarkers hold great potential for explaining and mitigating the associations between war zone-related PTSD and physical health problems, including cardiovascular and metabolic disorders.  In order to address this critical gap we will perform a pilot study to determine feasibility for larger scale biomarker identification and biomarker informed intervention studies by carefully examining 50 OIF/OEF warfighters through an extensive biological protocol.  The first phase will pilot the integration of methods across six leading research laboratories and identify the most promising biomarkers in preparation for the larger scale studies. Given the small sample size for the pilot and large number of biomarkers of interest, we will specify a limited set of biomarkers for hypothesis testing. It is predicted that compared with controls the PTSD group will have smaller dentate/CA3 hippocampal subfield volumes, lower ambient cortisol levels, greater cortisol suppression following dexamethasone administration, and actigraphy measures of decreased sleep efficiency and shorter sleep duration, and that decreased sleep duration and increased wake after sleep onset will be associated with decreased Dentate/CA3 volumes.