Suchergebnisse

The article of record as published may be located at http://dx.doi.org/10.1287 ; We develop a dynamic model in which Operation Iraqi Freedom (OIF) servicemembers incur a random amount of combat stress during each month of deployement, develop posttraumatic stress disorder (PTSD) if their cumulative stress exceeds a servicemember-specific threshold, and then develop symptoms of PTSD after an additional time lag. Using Department of Defense deployment data and Mental Health Advisory Team PTSD data to calibrate the model, we predict -- because of the long time lags and the fact that some surveyed servicemembers expeerience additional combat after being surveyed -- the fraction of Amry soldiers and Marines who eventually suffer from PTSD will be approximately twice as large as in the raw survey data. We cannot put a confidence interval around this estimate, but there is considerable uncertainty (perhaps plus/minus 30%). The estimate PTSD rate translates into approximately 300,000 PTSD cases among all Army soldiers and Marines in OIF, with approximately 20,000 new cases each year the war is prolonged. The heterogeneity of threshold levels among servicemembers suggests that although multiple deployments raise an individual's risk of PTSD, in aggregate, multiple deployments lower the total number of PTSD by approximately 30% relative to a hypothetical case in which the war was fought with many more servicemembers (i.e., a draft) deploying only once. The time lag dynamics suggest that, in aggregate, reserve servicemembers show symptoms aproximately 1-2 years before active servicemembers and predict that greater than 75% of OIF servicemembers who self-reported symptoms during their second deployment were exposed to the PTSD-generating stress during their first deployment. ; Naval Postgraduate School, Department of Operations Research, Monterey, CA; Stanford University, Stanford, CA