[1] Tulane Univ, Dept Psychiat & Behav Sci, Sch Med, New Orleans, LA 70118 USA
[2] Univ Pittsburgh, Dept Pediat, Sch Med, Pittsburgh, PA 15260 USA
[3] Univ Maryland, Dept Human Dev & Quantitat Methodol, College Pk, MD USA
[4] Inst Child Dev, Bucharest, Romania
[5] Boston Childrens Hosp, Boston, MA USA
[6] Harvard Med Sch, Boston, MA USA
[7] Harvard Grad Sch Educ, Cambridge, MA USA
[8] Vanderbilt Univ, Dept Psychol & Human Dev, Nashville, TN USA