[1] Stanford Univ, VA Palo Alto Hlth Care Syst, Natl Ctr PTSD, Stanford, CA 94305 USA
[2] Univ Penn, Sch Med, Philadelphia, PA 19104 USA
[3] Carl R Darnall Army Med Ctr, Ft Hood, TX USA
[4] Boston Univ, Sch Med, Massachusetts Vet Epidemiol Res & Informat Ctr, VA Boston Healthcare Syst, Boston, MA 02215 USA
[5] Univ Texas Hlth Sci Ctr San Antonio, San Antonio, TX 78229 USA
[6] Univ Texas Hlth Sci Ctr San Antonio, South Texas Vet Hlth Care Syst, San Antonio, TX 78229 USA