Psychopathy and the posterior hippocampus

Neurobiology of psychopathy is of interest, not only because neural underpi nnings of psychopathy remain obscure, but also because psychopaths may prov ide a model to study violent behavior, neurology of morals and impaired dec ision-making. Medial temporal lobe pathology has been suggested to be a par t of the neural systems dysfunction which manifests as violent and psychopa thic behavior. Yet, so far no sound evidence of neuroanatomical correlates for psychopathic behavior has been found. In this study regional hippocampa l volumes were measured using magnetic resonance imaging in 18 habitually v iolent offenders with antisocial personality disorder and type 2 alcoholism (derived from forensic psychiatric evaluation). The regional volumes along the anteroposterior axis of the hippocampus were correlated with the subje cts' degree of psychopathy as evaluated by the Psyhopathy Checklist-Revised . Strong negative correlations, up to - 0.79, were observed, among the stud y subjects, between the psychopathy scores and the posterior half of the hi ppocampi bilaterally. These data are in accordance with experimental studie s proposing that lesions of the dorsal hippocampus impair acquisition of co nditioned fear, and with theories on psychopathology according to which one of the central features in the birth of psychopathy is a deficit in acquis ition of conditioned fear. (C) 2001 Elsevier Science B.V. All rights reserv ed.