Background There are concerns regarding the validityof combatexposure reports of veterans seeking treatment for combat-relatedpost-traumatic stress disorder (PTSD) within USVeterans

Declaration of interest None. Fundingdetailed in Acknowledgements. There is extensive documentation of the prevalence, severity and correlates of posttraumatic stress disorder (PTSD) in Vietnam veterans exposed to the trauma of combat and war-zone service (Kulka et al, 1990). Research with Vietnam combat veterans has been used to create and refine the DSM criteria for PTSD (Shephard, 2001), to expand our knowledge base on the disorder and to allocate fiscal resources for the US Veterans Affairs treatment and disability programmes. Unfortunately, there is growing concern that there may be distortions in the PTSD database due to exaggeration or malingering related to secondary gain incentives among veterans (McNally, 2003). Furthermore, several authors have presented limited but compelling evidence that some Veterans Affairs research participants and patients may misrepresent their actual combat exposure (Burkett & Whitley, 1998). In our study we attempted to verify combat exposure history for a sample of individuals seeking treatment for Vietnam combat-related PTSD through objective historical data (i.e. US government military personnel files) available through the Freedom of Information Act. Historical government records have been used by others to address questions regarding the psychological consequences of war-zone experiences (Jones et al, 2002). Our study was conducted to determine whether there are treatment-seekers misrepresenting their Vietnam combat exposure in a Veterans Affairs specialty PTSD clinic. We also address questions about clinical symptom severity, symptom reporting style and use of Veterans Affairs services by veterans with and without documented combat exposure.