1 Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA and Division of Adolescent Medicine, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Oakland Medical Building, 3420 Fifth Avenue, Pittsburgh, PA 15213, USA.
2 Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA and RAND Corporation, 4570 Fifth Avenue, Suite 600, Pittsburgh, PA, USA.