The consistency of combat exposure reporting and course of PTSD in Vietnam War veterans.

Self-reports of traumatic events are often used in clinical and epidemiologic studies. Nevertheless, research suggests combat exposure reports may be biased by posttraumatic stress disorder (PTSD) symptom severity, leading to an inflated dose-response relation between combat exposure and PTSD. The authors examined the consistency in combat exposure reports and their relation to PTSD symptoms in Vietnam Veteran American Legionnaires who responded to two mailed surveys (1984, 1998; N = 1,462). Combat exposure reports were highly reliable (test-retest correlation = 0.87). However, changes in exposure reporting were related to changes in PTSD symptoms, specifically reexperiencing symptoms. The effect size of the dose-response relation attributable to changes in reporting was smaller for continuous than categorical measures. Findings are discussed in relation to recent controversies over veterans' combat exposure reports.