Individual differences in the treatment of psychopathic offenders

Psychopathy is a highly relevant clinical condition in forensic psychiatry. Its prevalence in the criminal justice system is quite high and it is associated with high risk of recidivism. Previous research has shown that psychopathic patients respond poorly to treatment, with high rates of treatment interfering behavior, aggressive incidents, and drop-out. Nevertheless, there are indications that treatment developed for high-risk (male) offenders in general may lead to reduction of recidivism for those psychopathic patients who do not drop out. The central question of this thesis is whether individual differences in psychopathic offenders can be used systematically to inform and improve their response to forensic psychiatric treatment. Throughout this thesis the Psychopathy Checklist-Revised (PCL-R) was used to assess psychopathy. Samples consisted of patients with a so-called TBS treatment order (“Terbeschikkingstelling”; at the disposal of the state). To pursue my main research question, we employed several different designs to examine individual differences in male patients with a high level of psychopathy and their impact on treatability. Results show that subtypes based on PCL-R scores do not appear to be clinically useful. However, several patient characteristics may indeed be relevant in systematically tailoring treatment to individual cases. Psychopathy in females has been studied substantially less. In the final study we examined the question of measurement invariance (MI) of the PCL-R with respect to gender. Establishing MI is a precondition for the comparability of male and female scores. Also, better fidelity in assessment is necessary for studying individual differences in females.