1. Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts.
2. The Fenway Institute, Fenway Health, Boston, Massachusetts.
3. Department of Global and Community Health, George Mason University, Fairfax, Virginia.
4. Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
5. Department of Global Health and Population, Harvard School of Public Health, Boston, Massachusetts.
6. OLB Research Institute, Online Buddies, Inc., Cambridge, Massachusetts.
7. Department of Psychiatry, Harvard Medical School, Boston, Massachusetts.
8. Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts.