1. Research Services, VA North Texas Health Care System, Dallas, TX 75216, USA
2. Mental Health, VA North Texas Health Care System, Dallas, TX 75216, USA
3. Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75390, USA
4. VA Central Western Massachusetts Healthcare System, Leeds, MA 01053, USA
5. Department of Population and Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA 01605, USA