The article you requested is

Does Combat Trauma Cause a Majority of PTSD Symptoms in Combat Veterans?

J Clin Psychiatry 2011;72(5):724-725 [letter]

Letter to the Editor

Because this piece does not have an abstract, we have provided for your benefit the first 3 sentences of the full text.

Gilbertson et al concluded that “the majority of psychiatric symptoms reported by combat veterans with PTSD [posttraumatic stress disorder] would not have been present were it not for their exposure to traumatic events.” This conclusion was based on a comparison between combat-exposed Vietnam veterans and identical male twins who were not exposed to combat trauma. I question whether the results truly support the conclusion that the majority of symptoms would not have been present, as an important factor contributing to reported psychopathology in veterans is compensation status.