Beyond Symptom Counts for Diagnosing Oppositional Defiant Disorder and Conduct Disorder?

Conduct Disorder (CD) and Oppositional Defiant Disorder (ODD) are among the most commonly diagnosed childhood behavioral health disorders. Although there is substantial evidence of heterogeneity of symptom presentations, DSM diagnoses of CD and ODD are formally diagnosed on the basis of symptom counts without regard to individual symptom patterns. We used unidimensional item response theory (IRT) two-parameter logistic (2PL) models to examine item parameters for the individual symptoms of CD and ODD using data on 6,491 adolescents (ages 13-17) from the National Comorbidity Study: Adolescent Supplement (NCS-A). For each disorder, the symptoms differed in terms of severity and discrimination parameters. As a result, some adolescents who were above DSM diagnostic thresholds for disruptive behavior disorders exhibited lower levels of the underlying construct than others below the thresholds, based on their unique symptom profile. In terms of incremental benefit, our results suggested an advantage of latent trait scores for CD but not ODD.