[1] Univ Calif Irvine, UCI Child Dev Ctr, Irvine, CA 92715 USA
[2] Univ Amsterdam, Amsterdam, Netherlands
[3] Inst Psychiat, Unit Child Psychiat, London, England
[4] Univ Southampton, Dept Psychol, Southampton SO9 5NH, Hants, England
[5] NIMH, Child & Adolescent Disorders Res Branch, Rockville, MD 20857 USA
[6] Univ Calif Los Angeles, Dept Psychiat & Biobehav Sci, Los Angeles, CA 90024 USA