“…First, although CD, ODD, ADHD, and depression undoubtedly have unique causal influences, there is evidence from twin studies that CD shares common genetic influences with ADHD (Coolidge, Thede, & Young, 2000;Thapar, Harrington, & McGuffin, 2001), with ODD (Coolidge et al, 2000;Eaves et al, 2000), and with depression (O'Connor, McGuire, Reiss, Hetherington, & Plomin, 1998). Second, there is evidence that CD shares common environmental risk factors with ODD and depression, such as negativity among family members and parenting that is low in warmth and monitoring (Fergusson, Lynskey, & Horwood, 1996;Frick et al, 1992;Ge, Best, Conger, & Simons, 1996;Goodman & Gotlib, 1999;Goodman et al, 1998;Pike, McGuire, Hetherington, Reiss, & Plomin, 1996). Third, there is evidence consistent with the hypothesis that childhood CD leads to family and peer rejection and academic failure, which give rise to depressive symptoms (Capaldi, 1992;Patterson & Capaldi, 1990;Patterson & Stoolmiller, 1991).…”