Notably, our dimensional results converged with previous taxometric analyses of other childhood externalizing disorders including childhood aggression (Walters et al., 2010), childhood psychopathy (Edens et al., 2011; Murrie et al., 2007), and ADHD (Marcus and Barry, 2011) as well as with FMM results of lifetime (child and adult) externalizing disorders, which included ODD (Witkiewitz et al., 2013). Certainly, our findings for the isolated construct of ODD within a child and adult cross-sectional sample using taxometric analyses, combined with the Witkiewitz et al.’s (2013) findings for broadly defined externalizing disorders (including ODD) within a longitudinal sample spanning from childhood to adulthood using FMM, provide robust evidence for the dimensional structure of ODD. Thus, it can be concluded that a diagnosis of ODD reflects a deviation in severity of behaviors that are found, at some level, in typical development, rather than reflecting the presence of some qualitatively distinct behavior that is typically not present.
