Background: No previous studies have compared the effectiveness of different modalities of psychotherapeutic treatment, as defined by different settings and durations, for patients with cluster C personality disorders. The aim of this multicentre study was to compare the effectiveness of 5 treatment modalities for patients with cluster C personality disorders in terms of psychiatric symptoms, psychosocial functioning, and quality of life. The following treatment modalities were compared: long-term outpatient (more than 6 months), short-term day hospital (up to 6 months), long-term day hospital, short-term inpatient, and long-term inpatient psychotherapy. Methods: The study was conducted between March 2003 and June 2008 in 6 mental health care centres in the Netherlands, with a sample of 371 patients with a DSM-IV-TR axis-II cluster C diagnosis. Patients were assigned to 5 different modalities of psychotherapeutic treatment, and effectiveness was assessed at 12 months after baseline. An intention-to-treat analysis was conducted for psychiatric symptoms (Brief Symptom Inventory), psychosocial functioning (Outcome Questionnaire-45), and quality of life (EQ-5D), using multilevel statistical modelling. As the study was non-randomised, the propensity score method was used to control for initial differences. Results: Patients in all treatment groups had improved on all outcomes 12 months after baseline. Patients receiving short-term inpatient treatment showed more improvement than patients receiving other treatment modalities. Conclusions: Psychotherapeutic treatment, especially in the short-term inpatient modality, is an effective treatment for patients with cluster C personality disorders.

Out-patient psychotherapy and day hospital psychotherapy are the optimal treatments for patients with cluster B personality disorders in terms of cost per recovered patient-year and cost per QALY.

Background: While psychopharmacological studies are common in patients with cluster A personality disorders, the effects of psychotherapy have received little attention. The aim of this study is to explore whether psychotherapeutic treatment yields health gains for these patients. Methods: The study was conducted between March 2003 and June 2008 in 6 mental health care centres in the Netherlands, with a sample of 57 patients with a DSM-IV-TR axis II cluster A diagnosis. Patients were assigned to 3 settings of psychotherapeutic treatment (outpatient, day hospital, inpatient), and effectiveness was assessed at 18 months after baseline. An intention-to-treat analysis was conducted for psychiatric symptoms (Brief Symptom Inventory), psychosocial functioning (Outcome Questionnaire-45) and quality of life (EQ-5D), using multilevel statistical modelling. As the study was non-randomised, the propensity score method was used to control for initial differences. Results: Patients in the day hospital and inpatient group improved substantially in terms of psychiatric symptoms, social and interpersonal functioning, and quality of life. Patients in the outpatient group showed less improvement. Direct comparison of the improvement of psychiatric symptoms showed significant results in favour of day hospital (p = 0.046) and inpatient (p = 0.01) treatment, as compared to outpatient treatment. However, due to substantial baseline differences, this direct comparison should be judged carefully. Conclusions: Cluster A psychopathology is not a contraindication to benefit from psychotherapy. This is especially true for more intensive forms like inpatient and day hospital treatment. Future research should focus more on psychotherapeutic treatment to gain further insight into effective treatment options for this patient group.

This study indicates that short-term day hospital psychotherapy and short-term inpatient psychotherapy are the most cost-effective treatment strategies for patients with cluster C personality disorders. The ultimate selection depends on what cost-effectiveness threshold is considered acceptable and what perspective is adopted.

The effectiveness of different modalities of psychotherapy in patients with PDNOS (i.e., short-term vs long-term; outpatient versus day hospital versus inpatient psychotherapy) has not yet been compared. Different modalities of psychotherapy are effective for patients with PDNOS, and positive effects remain after 5 years. In patients with PDNOS short-term (less than 6 months) outpatient psychotherapy and short-term inpatient psychotherapy seem to be superior to the four other treatment modalities at 12-month follow-up. At 60-month follow-up, treatments showed mostly comparable effectiveness.