[1] Univ Pittsburgh, Sch Med, Geriat Psychopharmacol Program, Pittsburgh, PA 15213 USA
[2] Univ Pittsburgh, Sch Med, Intervent Res Ctr Late Life Mood Disorders, Pittsburgh, PA 15213 USA
[3] Grad Sch Publ Hlth, Dept Human Genet, Pittsburgh, PA USA
[4] Grad Sch Publ Hlth, Dept Biostat, Pittsburgh, PA USA