Psychopathy and violence: the importance of factor level interactions.

The power of scales based on the Psychopathy Checklist (PCL; R. D. Hare, 1980) for prediction of violent behavior is well established. Although evidence suggests that this relationship is chiefly due to the impulsive and antisocial lifestyle component (Factor 2), the predictive power of psychopathy for violence may also reflect the multiplicative effects of this component with interpersonal and unemotional traits (Factor 1). The determination of the extent to which psychopathy subcomponents interact to predict violence has theoretical and practical implications for PCL-assessed psychopathy. However, the relationship between violence and the interactive effects of psychopathy subcomponents remains largely undetermined. The authors used prospective and cross-sectional designs to examine the independent and interactive effects of the factors of PCL-assessed psychopathy in 2 samples: (a) 199 county jail inmates and (b) 863 civil psychiatric patients. The Factor 1 x Factor 2 interaction predicted violence in both samples, such that the predictive power of Factor 2 was attenuated at lower levels of Factor 1.