Promising results from the pathway analysis of the CADD sample were followed up in two additional samples: the Minnesota Center for Twin and Family Research (MCTFR; N=3,378), a community-based adolescent sample (McGue et al. 2013, Miller et al. 2012), and the Study of Addiction: Genes and Environment (SAGE; N=3,988), a clinically over-selected study of addiction (Bierut et al. 2010; dbGaP study accession: phs000092.v1.p1). A phenotype similar to BD as defined in the CADD sample was available in the MCTFR sample (Hicks et al. 2010; McGue et al. 2013). The phenotype analysed in the SAGE sample was the average number of dependence symptoms for substances that each participant used. Full description of the MCTFR and SAGE samples is provided in the Supplement.
