Some might argue that our youth with CD and substance problems may have only engaged in conduct disorder behaviors while intoxicated. Although we cannot with certainty rule out that these adolescents suffered from substance-induced conduct symptoms, conduct disorder symptoms tend to predate the onset of substance use within individuals (Kuperman et al., 2001), early conduct problems predict later substance use disorders (Fergusson et al., 2005) and in one large epidemiological study the median age of onset for conduct disorder was much earlier than that for substance use disorders (Kessler et al., 2005); these data are consistent with the clinical histories common in our program.
