Objective Previous studies show that children with psychopathic traits may be less responsive to parenting. While harsh/inconsistent parenting is associated with increased problem behaviors in children low on psychopathic traits, children high on psychopathic traits show consistently high levels of problem behavior regardless of negative parenting. Moderating effects of child psychopathy on positive dimensions of parenting have not been explored. Method We applied multi-level regression models to test for interactions between child psychopathic traits and both positive and negative parental affect on individual differences in both reactive and proactive aggression in a community-based sample of 1,158 children aged 9–10. Results There were significant associations between psychopathy, and positive and negative parental affect with both forms of aggression. Child psychopathic traits also moderated effects of positive and negative parental affect. Children low on psychopathic traits showed decreasing reactive aggression as positive parental affect increased, and increasing levels of reactive aggression as negative parental affect increased, but children high on psychopathic traits showed more stable levels of reactive aggression regardless of levels of parental affect. Proactive aggression was more strongly associated with negative parental affect among children with higher levels of psychopathic traits. Conclusions In a community sample of pre-adolescent children, child psychopathic traits were shown to moderate the effects of parental affect on aggression. Reactive aggression in children high on psychopathic traits appears less responsive to variations in either positive or negative parenting. In contrast, child psychopathic traits may exacerbate the effects of high levels of negative parental effect on proactive aggression.

This study examined the genetic and environmental architecture underlying aggressive behavior measured by the Life History of Aggression Questionnaire (LHA; Coccaro et al. 1997a). Following preliminary phenotypic factor analysis procedures, multivariate behavioral genetics models were fit to responses from 2,925 adult twins from the PennTwins cohort on five LHA items assessing lifetime frequency of temper tantrums, indirect aggression, verbal aggression, fighting, and physical assault. The best-fitting model was a 2-factor common pathway model, indicating that these five aggressive behaviors are underpinned by two distinct etiological factors with different genetic and nonshared environmental influences. Although there was evidence of significant sex differences, the structure of the two factors appeared to be quite similar in males and females, where General Aggression and Physical Aggression factors emerged. Heritability of these factors ranged from .37 to .57, and nonshared environmental effects ranged from .43 to .63. The results of this study highlight the heterogeneous nature of the aggression construct and the need to consider differences in genetic and environmental influences on individual aggressive behaviors in a multivariate context.