Callous-unemotional traits and subtypes of conduct disorder.

There has been growing consensus that children with conduct disorder (CD) constitute a very heterogeneous group containing children who vary substantially on the development, course, and causes of the disorder. While many have recognized the importance of this heterogeneity for developing better causal theories and for developing more effective treatments, there has been little consensus as to the best way to subtype children with CD. In this paper, we review a number of approaches to subtyping, each with some evidence for its validity for certain purposes. We focus on two recent approaches that have great potential for integrating past subtyping approaches and for advancing causal theory. The first approach is the division of children with CD into those with a childhood onset to their severe antisocial behavior and those with an adolescent onset to their behavior. The second approach is to designate children within the childhood-onset group who show callous and unemotional traits, which is analogous to adult conceptualizations of psychopathy. Both approaches help designate children who many show different causal processes underlying their severe aggressive and antisocial behavior, and who may warrant different approaches to treatment.