Studies' Estimates of PTSD Prevalence Rates for Returning Service Members Vary Widely

In allocating resources to treat posttraumatic stress disorder PTSD among service members, policymakers rely on estimates of how prevalent this condition is among troops. But published prevalence rates vary extensively and are often disputed. For example, the most frequently cited estimate for PTSD among Vietnam veterans nearly 31 percent is still highly criticized. Similar concerns have been raised about PTSD prevalence estimates among U.S. service members serving in Afghanistan as part of Operation Enduring Freedom OEF and in Iraq as part of Operation Iraqi Freedom OIF. A team of RAND researchers analyzed the literature to document the extent of the variation in PTSD prevalence rates for military personnel who had served in OEF and OIF since 2002 and to identify possible explanations for these discrepancies.