Psychotherapeutic treatment effective for patients with cluster C personality disorders

A large prospective multicenter study headed by Prof. Paul Emmelkamp (Amsterdam), published in the current issue of Psychotherapy and Psychosomatics, unravels new promising data on the psychotherapeutic treatment of severe personality disturbances.

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 (PD) which encompasse avoidant, dependent, and obsessive-compulsive PD.

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.

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. 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. Psychotherapeutic treatment, especially in the short-term inpatient modality, is an effective treatment for patients with cluster C personality disorders.