Relationship between psychopathy, aggression, anger, impulsivity, and intermittent explosive disorder

Intermittent explosive disorder (IED) in DSM-5 represents a disorder of recurrent, problematic, reactive (i.e., affective or impulsive), aggressive behavior that, over the lifetime, affects about 5-6% of individuals in the United States. While aggression is also observed in those with psychopathic personality, aggression in this context is frequently proactive rather than reactive, and neurobiological study suggests important differences between those with proactive aggression/psychopathy and those with reactive aggression. In this paper, we conducted two sets of analyses. First, a phenomenologic study to explore the frequency of psychopathic personality defined by the Psychopathology Checklist-Screening Version (PCL-SV) among IED and comparator participants and to explore differences in measures of aggression, anger, and impulsivity as a function of IED and psychopathic personality. Second, we re-analyzed data from five published studies to determine if psychopathic personality accounted for differences between IED and comparator participants. The first study found that only a modest proportion of IED participants display clinically substantial features of psychopathy and that measures of trait aggression and anger, rather than those of psychopathy, are the strongest correlates of IED. The second study found little evidence for any impact of psychopathy on reported findings in IED compared with various control participants.