[1] Yale Univ, Sch Med, Natl Clinician Scholars Program, New Haven, CT USA
[2] Yale Univ, Sch Med, Dept Pediat, New Haven, CT 06510 USA
[3] Yale Univ, Sch Med, Dept Emergency Med, New Haven, CT 06510 USA
[4] Yale Univ, Sch Med, Yale Child Study Ctr, New Haven, CT USA
[5] Univ Calif Los Angeles, UCLA Semel Inst Neurosci & Human Behav, Los Angeles, CA USA
[6] Northwestern Univ, Div Emergency Med, Ann & Robert H Lurie Childrens Hosp Chicago, Chicago, IL 60611 USA
[7] Northwestern Univ, Feinberg Sch Med, Chicago, IL 60611 USA
[8] Ctr Outcomes Res & Evaluat, New Haven, CT USA