Our final between-group contrasts centered on comorbidity with other disorders in childhood and adolescence and prediction to psychiatric outcomes in early adult life. Across all childhood and adolescent observations, rates of comorbidity were largely similar. Early adult outcomes provided a more differentiated picture. Increased risks of ASPD symptoms in adulthood were largely confined to cases with prior histories of CD. In contrast, a history of ODD was associated with some increased risk for depression, and with markedly increased risk for anxiety in early adulthood. Strikingly, cases in the CD only group were at significantly lower risk for anxiety disorders than youth with no prior history of ODD or CD. Copeland et al.’s (2009) analyses of the GSMS also provide evidence of poor adult psychiatric functioning following ODD. Taken together, these findings on longer-term outcomes provide less support for a model of ODD as a milder form of CD, and point more in the direction of the two disorders representing distinct forms of psychopathology. This indicates, therefore, that the hierarchical relationship between ODD and CD specified in DSM-IV should be abandoned. Our final set of analyses was designed to test whether distinguishable dimensions of disorder could be identified within ODD.
