1. Department of Veterans Affairs, VISN 17 Center of Excellence for Research on Returning War Veterans, Waco, TX, USA;
2. Department of Psychiatry, Texas A&M College of Medicine, Bryan, TX, USA;
3. Department of Health, Human Performance and Recreation, Baylor University, Waco, TX, USA;
4. Department of Psychology and Neuroscience, Baylor University, Waco, TX, USA;
5. Institute of Biomedical Studies, Baylor University, Waco, TX, USA;
6. Center for Vital Longevity, University of Texas at Dallas, Dallas, TX, USA