[1] Virginia Commonwealth Univ, Dept Psychiat, Richmond, VA 23298 USA
[2] Virginia Commonwealth Univ, Virginia Inst Psychiat & Behav Genet, Richmond, VA 23298 USA
[3] Queens Univ, Dept Psychiat, Belfast, Antrim, North Ireland
[4] Hlth Res Board, Dublin, Ireland
[5] Georgetown Univ, Med Ctr, Washington VA Med Ctr, Schizophrenia Res Program, Washington, DC 20007 USA