Psychopathy (PCL-R) in a forensic psychiatric sample of homicide offenders: some reliability issues

Several studies have shown that psychopathy is overrepresented among homicide offenders. There is a consensus that Hare's Psychopathy Checklist-Revised PCL-R is currently the most valid and useful tool for rating psychopathy (e.g., [Fulero, S. M. (1995). Review of the Hare Psychopathy Checklist-Revised. In J. C. Conoley & J. C. Impara (Eds.), Twelfth Mental Measurements Yearbook (pp. 453-454). Lincoln, NE: Buros Institute]). Usually, when making a rating of psychopathy, both an interview and an examination of the subject's files are used. However, it has been discussed what is really required to be able to rate psychopathy in a reliable manner. The aim of the present study was to retrospectively rate the degree of psychopathy in 35 homicide offenders being subjected to forensic psychiatric assessment. These ratings of psychopathy were carried out using forensic psychiatric files and courts'; verdicts only. Another aim was to examine the reliability of PCL-R in this specific Swedish sample of homicide offenders. There was a good agreement between the two raters with respect to the categorical diagnosis of psychopathy (Cohen's kappa=.81, p<.001), which indicates that retrospective ratings of psychopathy are well suited for research purposes. The prevalence of psychopathy among the homicide offenders was 31.4% (using a cut-off score of 30), which means that the construct of psychopathy may contribute to the understanding of the phenomenon of homicide. In the planning of treatment for homicide offenders, a consideration of possible psychopathy is necessary. As criminal psychopaths are known to relapse into violent criminality, it is very important that they are given efficient treatment, placement and management.