The aim of this thesis was to investigate differences between conduct disorder with high versus low levels of callous-unemotional traits. Differences in parenting, grey matter volume and facial emotion recognition ability were investigated using univariate and machine learning methods. In Chapter 3, youths with conduct disorder experienced more negative and less positive parenting than typically developing youths. The high callous-unemotional group also experienced less positive parenting than the low callous-unemotional group. All groups were classified with above-chance accuracy. In Chapter 4, when controlling for ADHD, youths with conduct disorder exhibited reduced grey matter volume in the insulae relative to typically developing youths. Youths with conduct disorder and high callous-unemotional traits exhibited additional reductions in the left orbitofrontal cortex. All groups were classified with above-chance accuracies. In Chapter 5, youths with conduct disorder – regardless of callous-unemotional traits – were poorer at recognising emotions than typically developing youths. Youths with conduct disorder were classified against typically developing youths at above-chance levels, but the classifier did not exceed chance when distinguishing between high and low callous-unemotional groups. Together, these findings indicate both similarities and differences in conduct disorder with high versus low levels of callous-unemotional traits, consistent with different developmental pathways to similar outcomes
