“…Especially in the measurement context, it also implies a hierarchical structure (grading) of symptom severity. While there is some controversy over the complex relationships of ADHD and CD symptoms, e.g., whether CD is simply a more severe form of ADHD, whether CD develops as children with ADHD get older, whether there are both separate diagnoses of ADHD and CD as well as a hybrid of the two (Szatmari, Boyle, & Offord, 1989), it is increasingly common to subsume these disorders under the unidimensional construct of externalizing disorders (Cohen, Gotlieb, Kershner, & Wehrspann, 1985; Rapport, LaFond, & Sivo, 2009). …”