Children with conduct problems and high callous-unemotional (CP+CU) traits are characterized by dampened emotional responding, limiting their ability for affective empathy and impacting the development of prosocial behaviors. However, research documenting this dampening in young children is sparse and findings vary, with attachment-related stimuli hypothesized to ameliorate deficits in emotional responding. Here we test emotional responsiveness across various emotion-eliciting stimuli using multiple measures of emotional responsiveness (behavioral, physiological, self-reported) and attention, in young children aged 2–8 years (M age = 5.37), with CP+CU traits (CP+CU; n = 36), CPs and low CU traits (CP−CU; n = 82) and a community control sample (CC; n = 27). We found no evidence that attachment-related stimulus ameliorated deficits in emotional responding. Rather, at a group level we found a consistent pattern of reduced responding across all independent measures of responsiveness for children with CP+CU compared to the CC group. Few differences were found between CP+CU and CP−CU groups. When independent measures were standardized and included in a regression model predicting to CU trait score, higher CU traits were associated with reduced emotional responding, demonstrating the importance of multimodal measurement of emotional responsiveness when investigating the impact of CU traits in young children.

Contemporary theories of early development and emerging child psychopathology all posit a major, if not central role for physiological responsiveness. To understand infants’ potential risk for emergent psychopathology, consideration is needed to both autonomic reactivity and environmental contexts (e.g., parent–child interactions). The current study maps infants’ arousal during the face-to-face still-face paradigm using skin conductance (n = 255 ethnically-diverse mother–infant dyads; 52.5% girls, mean infant age = 7.4 months; SD = 0.9 months). A novel statistical approach was designed to model the potential build-up of nonlinear counter electromotive force over the course of the task. Results showed a significant increase in infants’ skin conductance between the Baseline Free-play and the Still-Face phase, and a significant decrease in skin conductance during the Reunion Play when compared to the Still-Face phase. Skin conductance during the Reunion Play phase remained significantly higher than during the Baseline Play phase; indicating that infants had not fully recovered from the mild social stressor. These results further our understanding of infant arousal during dyadic interactions, and the role of caregivers in the development of emotion regulation during infancy.

The role of environmental adversity in the development of high callous–unemotional (CU) traits in children is controversial. Evidence speaks to the traits being largely independent of adversity; however, recent data shows that those with high CU traits and high adversity and/or high anxiety might differ in important ways from those with no such history. We tested this using emotion recognition (ER) skills. We tested whether maltreatment history and anxiety levels moderated the relationship between level of CU traits and ER skills in N = 364 children with behavioral problems who were 3 to 16 years old. As hypothesised, in the full sample, the relationship between CU traits and ER differed according to maltreatment history, such that CU traits were associated with poorer recognition for those with zero or negligible history of maltreatment. This moderation of the CU-ER relationship by maltreatment was inconsistent across subgroups, however, and for the cohort utilizing youth self-report of maltreatment, high CU traits were associated with poor ER in those with lower anxiety levels. Maltreatment history and/or anxiety levels can identify different emotional impairments associated with high CU traits, and the impairments might be characteristic of “primary” high CU traits defined as occurring independently of maltreatment and/or high anxiety.

The co-occurrence of child conduct problems (CPs) and callous–unemotional (CU) traits confers risk for psychopathy. The oxytocin (OXT) system is a likely candidate for involvement in the development of psychopathy. We tested variations in the OXT receptor gene (OXTR) in CP children and adolescents with varying levels of CU traits. Two samples of Caucasian children, aged 4–16 years, who met DSM criteria for disruptive behavior problems and had no features of autism spectrum disorder, were stratified into low versus high CU traits. Measures were the frequencies of nine candidate OXTR polymorphisms (single nucleotide polymorphisms). In Sample 1, high CU traits were associated with single nucleotide polymorphism rs1042778 in the 3′ untranslated region of OXTR and the CGCT haplotype of rs2268490, rs2254298, rs237889, and rs13316193. The association of rs1042778 was replicated in the second rural sample and held across gender and child versus adolescent age groups. We conclude that polymorphic variation of the OXTR characterizes children with high levels of CU traits and CPs. The results are consistent with a hypothesized role of OXT in the developmental antecedents of psychopathy, particularly the differential amygdala activation model of psychopathic traits, and add genetic evidence that high CU traits specify a distinct subgroup within CP children.

Child conduct problems (CPs) are a robust predictor of adult mental health; the concurrence of callous–unemotional (CU) traits confers specific risk for psychopathy. Psychopathy may be related to disturbances in the oxytocin (OXT) system. Evidence suggests that epigenetic changes in the OXT receptor gene (OXTR) are associated with lower circulating OXT and social–cognitive difficulties. We tested methylation levels of OXTR in 4- to 16-year-old males who met DSM criteria for a diagnosis of oppositional–defiant or conduct disorder and were stratified by CU traits and age. Measures were DNA methylation levels of six CpG sites in the promoter region of the OXTR gene (where a CpG site is a cytosine nucleotide occurs next to a guanine nucleotide in the linear sequence of bases along its lenth, linked together by phosphate binding), and OXT blood levels. High CU traits were associated with greater methylation of the OXTR gene for two cytosine nucleotide and guanine nucleotide phosphate linked sites and lower circulating OXT in older males. Higher methylation correlated with lower OXT levels. We conclude that greater methylation of OXTR characterizes adolescent males with high levels of CU and CPs, and this methylation is associated with lower circulating OXT and functional impairment in interpersonal empathy. The results add genetic evidence that high CU traits specify a distinct subgroup within CP children, and they suggest models of psychopathy may be informed by further identification of these epigenetic processes and their functional significance.