At every assessment, ES twins participate in a psychophysiological laboratory assessment. Fathers complete this assessment at their intake and second follow-up visits, while mothers complete this assessment at their first follow-up. The ES study employs developmentally sensitive laboratory tasks designed to tap genetic risk for substance use disorders and childhood disruptive disorders, individual differences in inhibitory control, and putative frontal lobe indices of executive functioning relevant to adolescent brain development. We also include procedures tapping autonomic nervous system (ANS) function and measures of negative affect, which have received considerably less attention in the substance abuse literature, both for their potential as endophenotypes and for illuminating mechanisms underlying the role of affect dysregulation in the development of substance use disorders (see Table 2).
