The 9/11 terrorist attack and posttraumatic stress disorder revisited.

Research published in the aftermath of the 9/11 terrorist attack reported elevated rates of posttraumatic stress disorder (PTSD) in the US population (4.3%-17.0%), attributable to indirect exposure through the media. We use data from a national survey conducted in 2004 to 2005 (National Epidemiologic Survey on Alcohol and Related Conditions Wave 2) (n = 34,653). The list of traumatic events covered in the survey included indirect exposure to 9/11 through media coverage. Respondents who endorsed more than 1 traumatic event were asked to single out "the worst event" they had ever experienced. The worst event (or the only event) was the index event for diagnosing PTSD. Indirect experience of 9/11 had the lowest PTSD risk of all the traumatic events in the list, 1.3%. In the subset that endorsed only 9/11 indirect exposure (n = 3981), the PTSD risk was 0.3%. Of the total sample, 0.7% experienced PTSD in relation to indirect 9/11. Explanations for the lower estimates are discussed.