1. Department of Veterans Affairs, War Related Illness and Injury Study Center (WRIISC) , Washington, DC 20422 , USA
2. Department of Psychiatry, Georgetown University Medical School , Washington, DC 20007, USA
3. Henry M. Jackson Foundation for the Advancement of Military Medicine Inc. , Bethesda, MD, USA
4. Department of Veterans Affairs, Health Outcomes Military Exposures (HOME) , Washington, DC 20420, USA
5. Department of Preventive Medicine and Biostatistics, Uniformed Services University , Bethesda, MD 20814, USA