There were no differences in offspring age or sex by parental AD or cannabis dependence. Offspring of separated parents were slightly older (r=0.19, p<0.0001), with no differences in offspring sex by parental separation. Twin parents with a history of AD or cannabis dependence were slightly younger at the 1997–2002 assessment (r=−0.06 and −0.07, p<0.05, respectively), with fewer female twins than male meeting criteria for either disorder [OR=0.54 (95%CI: 0.42–0.70) and OR=0.55 (95%CI: 0.38–0.80), respectively]. Differences by parental separation in twin age or sex were nonsignificant. Compared to unaffected twins, rates of parental separation were higher for twins with a history of AD [OR=2.06 (95%CI: 1.58–2.69)] or cannabis dependence [OR=3.69 (95%CI: 2.55–3.85)]. Twin AD and cannabis dependence were moderately correlated (polychoric r=0.55, p<0.0001).
