Participants with genetic and relevant phenotypic data were ascertained from the CADD projects; full details of participant selection for inclusion in the GWAS sample are provided in the Supplemental materials. GWAS participants were drawn from several primary studies described elsewhere (Hartman et al. 2008, Petrill et al. 2003, Rhea et al. 2006, Stallings et al. 2005). The current sample of 1,901 unrelated adolescents was over-selected for adolescent BD, with half of the participants ascertained specifically from high-risk populations (i.e. recruited through substance abuse treatment, special schools, or involvement with the criminal justice system; see Supplement for additional criteria for clinical probands). CADD GWAS participants had an average age of 16.5 (SD=1.4, range=13.0–19.9), 28.9% were female, and 37.3% of participants reported non-Caucasian ancestry (primarily Hispanic or African; see Supplemental Table S1 for complete demographic statistics).
