1. Mental Health Service, San Francisco VA Health Care System , San Francisco, CA 94121, USA
2. Department of Psychiatry and Behavioral Sciences, University of California , San Francisco, CA 94143, USA
3. Department of Medicine, University of California , San Francisco, CA 94143, USA
4. Research Service, San Francisco VA Health Care System , San Francisco, CA 94121, USA
5. National Center for PTSD, Dissemination and Training Division, VA Palo Alto Healthcare System , Menlo Park, CA 94025, USA
6. Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine , Stanford, CA 94305, USA