assessment and participation rates did not vary by screening status. Differences in socioeconomic and demographic factors between participating and eligible but non-participating families were generally minimal (Keyes et al., 2009). In addition, 48 pairs of MZ twins aged 14–16 at initial assessment were recruited from the same population as the ES families and assessed one year apart. The twins in these families were part of a pilot study on adolescent brain development (AdBrain) and completed a clinical assessment similar to that used in ES along with both structural and functional MRIs. Twins in this study were also included in the GWAS sample.
