Effects of Iraq/Afghanistan deployments on PTSD diagnoses for still active personnel in all four services.

We estimate the effect of deployment location and length on risk of developing post-traumatic stress disorder (PTSD). We draw a random sample of active duty enlisted personnel serving between 2001 and 2006 from a TRICARE beneficiary database and link deployment characteristics from the contingency tracking system. Using logistic regressions, we found that deployment to Iraq/Afghanistan increases the odds of developing PTSD substantially, relative to those in other duties, with the largest effect observed for the Navy (OR = 9.06, p < 0.01) and the smallest effect for the Air Force (OR = 1.25, p < 0.01). A deployment longer than 180 days increases the odds of PTSD by 1.11 to 2.84 times compared to a short tour. For Army and Navy, a deployment to Iraq/Afghanistan further exacerbates the adverse effect of tour length.