1. a Department of Psychiatry and Behavioral Sciences , Duke University School of Medicine , Durham, North Carolina, USA
2. b Department of Health Policy and Management and Department of Psychiatry , University of North Carolina at Chapel Hill , Chapel Hill, North Carolina, USA
3. c Deputy Director for Research, Cecil G. Sheps Center for Health Services Research , University of North Carolina at Chapel Hill , Chapel Hill, North Carolina, USA
4. d Department of Health Policy and Management, Gillings School of Global Public Health , University of North Carolina at Chapel Hill , Chapel Hill, North Carolina, USA