1. Seattle Epidemiologic Research and Information Center Department of Veterans Affairs Seattle Washington USA
2. Department of Psychiatry Medical University of South Carolina Charleston South Carolina USA
3. Department of Epidemiology Rollins School of Public Health Emory University Atlanta Georgia USA
4. Massachusetts Veterans Epidemiological Research and Information Center US Department of Veteran Affairs Boston Massachusetts USA
5. Department of Psychiatry Boston University Boston Massachusetts USA
6. Department of Psychiatry Dartmouth Geisel School of Medicine Hanover New Hampshire USA
7. National Center for PTSD U.S. Department of Veterans Affairs Washington District of Columbia USA
8. Department of Epidemiology University of Washington Seattle Washington USA