The four-factor model of the Psychopathy Checklist--Revised: validation in a Dutch forensic inpatient sample.

In The Netherlands, the Ministry of Security and Justice requires the assessment of the Psychopathy Checklist-Revised (PCL-R; Hare, 1991; Hare, 2003) in all forensic psychiatric inpatients. To examine the four-factor structure of the Psychopathy Checklist-Revised, confirmatory factor analysis (CFA) was conducted using a Dutch sample of forensic psychiatric inpatients (N=411) and the results indicated acceptable fit. Also, using multiple group CFA, the four-factor model provided an acceptable fit in both patients with a personality disorder and patients with a psychotic disorder, and there was reasonably good evidence of measurement invariance between these two subgroups. Furthermore, correlations with external measures of aggression and personality traits provided additional support for the validity of the four-factor model in patients with a personality disorder. In patients with a psychotic disorder fewer significant correlations with external measures were found. Taken together, the results support the use of the four-factor structure in Dutch offenders who are detained under hospital order.