1. Department of Medicine (Bartels) and Department of Psychiatry (Freudenreich), Harvard Medical School, Boston; Mongan Institute (Bartels), Boston Health Care for the Homeless Program, Institute for Research, Quality, and Policy in Homeless Health Care (Baggett), and Department of Medicine (Bartels) and Department of Psychiatry (Freudenreich), Massachusetts General Hospital, Boston; Vinfen, Cambridge, Massachusetts (Bird). Marvin S. Swartz, M.D., is editor of this column.