Current research on psychopathy: Neuropsychological findings and neurobiological hypotheses

A reliable and valid diagnosis of psychopathy can now be made using Hare's Psychopathy Checklist-Revised (PCL-R; Hare, 1991). This new diagnostic procedure identifies the most persistent and violent criminals. Given that a reliable and valid diagnosis can now be made, research aimed at identifying the causes of this disorder can be undertaken. This article reviews the literature on the biological bases of psychopathy. The problem is intriguing: psychopaths show no deficits on standard batteries of neuropsychological tests, yet findings suggest an orbital-frontal dysfunction. Despite an IQ well within normal limits, psychopaths evidence learning deficits and difficulty in inhibiting responses while being able to attend to events of immediate interest. They are distinguished by weak emotional anticipation of unpleasant events and a lack of reaction to emotionally charged stimuli. They are relatively insensitive to the emotional connotation of words. Language functions are diffuse and appear to be localized in both hemispheres. It is hypothesized that the principal determinant of psychopathy is an early abnormality in the development of the limbic system which in turn leads to a cortical reorganization of language.