Hippocampal structural asymmetry in unsuccessful psychopaths

Background Structural and functional hippocampal abnormalities have been previously reported in institutionalized psychopathic and aggressive populations. This study assessed whether prior findings of a right greater than left (R> L) functional asymmetry in caught violent offenders generalize to the structural domain in unsuccessful, caught psychopaths. Methods Left and right hippocampal volumes were assessed using structural magnetic resonance imaging (MRI) in 23 control subjects, 16 unsuccessful psychopaths, and 12 successful (uncaught) community psychopaths and transformed into standardized space. Results Unsuccessful psychopaths showed an exaggerated structural hippocampal asymmetry (R> L) relative both to successful psychopaths and control subjects (p< .007) that was localized to the anterior region. This effect could not be explained by environmental and diagnostic confounds and constitutes the first brain imaging analysis of successful and unsuccessful psychopaths. Conclusions Atypical anterior hippocampal asymmetries in unsuccessful psychopaths may reflect an underlying neurodevelopmental abnormality that disrupts hippocampal-prefrontal circuitry, resulting in affect dysregulation, poor contextual fear conditioning, and insensitivity to cues predicting capture.