1. Department of Community Medicine, Mercer University School of Medicine, Macon, Georgia.
2. Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Asher Center for the Study and Treatment of Depressive Disorders, Northwestern University, Chicago, Illinois.
3. Departments of Epidemiology and Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania.
4. University Center for Social and Urban Research, University of Pittsburgh, Pittsburgh, Pennsylvania.
5. Graduate School of Public Health, Epidemiology Data Center, University of Pittsburgh, Pittsburgh, Pennsylvania.