[1] Harvard Univ, Sch Publ Hlth, Dept Soc Human Dev & Hlth, Boston, MA 02115 USA
[2] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA
[3] Massachusetts Gen Hosp, Dept Psychiat, Boston, MA 02114 USA
[4] Weill Cornell Med Coll, Dept Psychiat, White Plains, NY 10605 USA
[5] Univ Penn, Sch Med, Dept Biostat & Epidemiol, Philadelphia, PA 19104 USA
[6] Univ Toronto, Ctr Addict & Mental Hlth, Dept Psychiat, Toronto, ON M6J 1H4, Canada
[7] Univ Pittsburgh, Dept Psychiat, Pittsburgh, PA 15213 USA
[8] Univ London London Sch Hyg & Trop Med, Fac Epidemiol & Populat Hlth, London WC1E 7HT, England