Biological Correlates of Conduct Disorder and Callous-Unemotional Traits

Callous-unemotional (CU) traits have been proposed to identify a unique subgroup of children with conduct disorder (CD). Little is known, however, about the biological correlates of these traits. In addition, research into the biological correlates of CD has been mixed. This dissertation tested the hypothesis that CU traits moderate the relationship between CD and biological indicators of activity in the central nervous system, the autonomic nervous system, and the hypothalamic-pituitary-adrenal (HPA) axis. Specifically, CU traits were expected to be associated with decreased arousal at rest and in response to stress, whereas it was predicted that symptoms of CD would be associated with decreased arousal at rest and increased arousal in response to stress. These hypotheses were tested in a community sample of 11-12 year old children (N = 446). Symptoms of CD were assessed using childand caregiver-report, and both the child and the caregiver reported on levels of CU traits using the Antisocial Process Screening Device (APSD). Section 1 focused on electroencephalography (EEG) recorded during an eyes-open rest period. CU traits were associated with a marginally significant increase in theta power in African American participants. In participants of other races, CU traits predicted significantly decreased theta, alpha, and beta power. CD was not significantly associated with EEG in any frequency band. Section 2 examined heart rate (HR) and skin conductance level (SCL) at rest and in response to a modified version of the Trier Social Stress Test (TSST). Heart rate was negatively associated with CU traits, but it was not significantly associated with symptoms of CD. CD symptoms and CU traits interacted to predict SCL such that CD was negatively associated with SCL, but only in the context of low levels of CU traits. Section 3 investigated cortisol response to the TSST. Results indicated that CD was positively associated with total cortisol production (as measured by area under the curve with respect to ground [AUCG]), whereas CU traits were negatively associated with AUCG at a trend level. Overall, these results suggest that the biological correlates of CU traits differ from those of CD as a whole, with CU traits being associated with hypoarousal and CD symptoms being associated with a pattern indicating impulsivity. These divergent results for CD and CU may imply that children with CD who are high in CU traits have different treatment needs compared to children with CD who are low in CU traits. Degree Type Dissertation Degree Name Doctor of Philosophy (PhD) Graduate Group Psychology First Advisor Adrian Raine This dissertation is available at ScholarlyCommons: http://repository.upenn.edu/edissertations/1986