Personality disorders in a Dutch forensic psychiatric sample: changes with treatment

Evidence on the effectiveness of treatment for personality disorder (PD) is mixed, and there are very few data at all on outcomes for offender patients with PD. In the Netherlands there is nevertheless commitment to treating such people in specialized forensic psychiatric hospitals.

The main aim was to determine the extent to which, if at all, patients detained under the Dutch TBS provision in the Dr Henri Van der Hoeven Hospital changed during inpatient treatment.

The study followed a naturalistic design. On admission, the Structured Interview for DSM Personality Disorders (SIDP-R) and the Personality Diagnostic Questionnaire-Revised (PDQ-R) were used to assess DSM axis-II personality disorder pathology. After two years of intensive treatment they were reassessed using self-report questionnaires.

Fifty-nine patients (54 men and five women) completed both ratings. At follow-up, group mean indicated a significant reduction in personality disorder pathology as measured by the PDQ-R. Analysis of changes in individual subjects according to a method described by Jacobson and Truax (1991) showed that almost 40% improved reliably (by more than two standard deviations) and more than one quarter of the sample improved to a reliable and clinically significant extent in personality disorder features.

The findings of the study are encouraging in terms of reduction of personality disorder psychopathology. Limitations to the study design are acknowledged. Further, it is not known whether this change constitutes substantial reorganization of personality, or whether it reflects a change at a more superficial level. Further follow-up of the patients is necessary to investigate whether the positive changes remain after release from hospital.