Context
The population of men who display persistent antisocial and violent behavior is heterogeneous. Callous-unemotional traits in childhood and psychopathic traits in adulthood characterize a distinct subgroup.
Objective
To identify structural gray matter (GM) differences between persistent violent offenders who meet criteria for antisocial personality disorder and the syndrome of psychopathy (ASPD+P) and those meeting criteria only for ASPD (ASPD−P).
Design
Cross-sectional case-control structural magnetic resonance imaging study.
Setting
Inner-city probation services and neuroimaging research unit in London, England.
Participants
Sixty-six men, including 17 violent offenders with ASPD+P, 27 violent offenders with ASPD−P, and 22 healthy nonoffenders participated in the study. Forensic clinicians assessed participants using the Structured Clinical Interview for DSM-IV and the Psychopathy Checklist–Revised.
Main Outcome Measures
Gray matter volumes as assessed by structural magnetic resonance imaging and volumetric voxel-based morphometry analyses.
Results
Offenders with ASPD+P displayed significantly reduced GM volumes bilaterally in the anterior rostral prefrontal cortex (Brodmann area 10) and temporal poles (Brodmann area 20/38) relative to offenders with ASPD−P and nonoffenders. These reductions were not attributable to substance use disorders. Offenders with ASPD−P exhibited GM volumes similar to the nonoffenders.
Conclusions
Reduced GM volume within areas implicated in empathic processing, moral reasoning, and processing of prosocial emotions such as guilt and embarrassment may contribute to the profound abnormalities of social behavior observed in psychopathy. Evidence of robust structural brain differences between persistently violent men with and without psychopathy adds to the evidence that psychopathy represents a distinct phenotype. This knowledge may facilitate research into the etiology of persistent violent behavior.