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The Genetic and Environmental Covariation Among Psychopathic Personality Traits, and Reactive and Proactive Aggression in Childhood


  • The authors wish to thank the USC Twin Project staff for assistance in data collection and scoring, and the twins and their families for their participation in this research. This study was supported by grants to Serena Bezdjian from NIMH (F31-MH068953) and NIDA (T32-DA07313), to Laura Baker from NIMH (R01 MH58354), and to Adrian Raine from NIMH (Independent Scientist Award K02 MH01114-08). Catherine Tuvblad was supported by postdoctoral stipends from the Swedish Council for Working Life and Social Research (Project 2006-1501) and the Sweden-America Foundation.

concerning this article should be addressed to Serena Bezdjian, Department of Psychology, University of Southern California, 3620 S. McClintock Ave., Los Angeles, CA 90089-1061. Electronic mail may be sent to


The present study investigated the genetic and environmental covariance between psychopathic personality traits with reactive and proactive aggression in 9- to 10-year-old twins (N = 1,219). Psychopathic personality traits were assessed with the Child Psychopathy Scale (D. R. Lynam, 1997), while aggressive behaviors were assessed using the Reactive Proactive Questionnaire (A. Raine et al., 2006). Significant common genetic influences were found to be shared by psychopathic personality traits and aggressive behaviors using both caregiver (mainly mother) and child self-reports. Significant genetic and nonshared environmental influences specific to psychopathic personality traits and reactive and proactive aggression were also found, suggesting etiological independence among these phenotypes. Additionally, the genetic relation between psychopathic personality traits and aggression was significantly stronger for proactive than reactive aggression when using child self-reports.

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