[1] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA
[2] Harvard Univ, Sch Publ Hlth, Dept Soc Human Dev & Hlth, Boston, MA 02115 USA
[3] Harvard Univ, Sch Med, Dept Psychiat, Boston, MA 02115 USA
[4] Harvard Univ, Sch Publ Hlth, Dept Biostat, Boston, MA 02115 USA
[5] McLean Hosp, Lab Psychiat Biostat, Belmont, MA 02178 USA
[6] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Populat Family & Reprod Hlth, Baltimore, MD USA
[7] Harvard Univ, Ctr Developing Child, Cambridge, MA 02138 USA