Group schema therapy for cluster‐C personality disorders: A multicentre open pilot study

• Published in: Clinical psychology and psychotherapy 2023-11, Vol.30 (6), p.1279-1302
• Main Authors: Wibbelink, Carlijn J. M., Venhuizen, Anne‐Sophie S. M., Grasman, Raoul P. P. P., Bachrach, Nathan, Hengel, Charlotte, Hudepohl, Sandy, Kunst, Liselotte, Lange, Hinde, Louter, Mark A., Matthijssen, Suzy J. M. A., Schaling, Arita, Walhout, Simone, Wichers, Karen (Renske), Arntz, Arnoud
• Format: Article
• Language: English
• Subjects: avoidant, dependent and obsessive‐compulsive personality disorders; cluster‐C personality disorders; effectiveness; group schema therapy; Personality; Personality disorders; pilot study; Quality of life
• ISSN: 1063-3995; 1099-0879
• DOI: 10.1002/cpp.2903

Background Group schema therapy (GST) is increasingly popular as a treatment for personality disorders (PDs), including Cluster‐C PDs. Individual ST has proven to be effective for Cluster‐C PD patients, while the evidence for GST is limited. This study aimed to investigate the effectiveness of GST for Cluster‐C PD. Moreover, differences between the specific Cluster‐C PDs (avoidant PD, dependent PD and obsessive‐compulsive PD) were explored. Methods A multicentre open trial was conducted, including 137 patients with a Cluster‐C PD (avoidant PD: n = 107, dependent PD: n = 11 and obsessive‐compulsive PD: n = 19). Patients received 30 weekly GST sessions with a maximum of 180 min of individual ST and five optional monthly booster sessions. Outcome measures including Cluster‐C PD severity, general psychopathological symptoms, quality of life, functional impairment, happiness, PD‐related beliefs, self‐esteem, self‐ideal discrepancy, schemas and schema modes were assessed at baseline until 2‐year follow‐up with semi‐structured interviews and self‐report measures. Change over time and differences between the specific Cluster‐C PDs were analysed with mixed regression analyses. Results The outcome measures showed significant improvements for all Cluster‐C PDs, with medium to large effect sizes after 2 years. A treatment dropout rate of 11.7% was found. There were some indications for differences between the Cluster‐C PDs in severity at baseline, change trajectories and effectiveness of GST. Conclusions This study demonstrated that GST is a promising treatment for Cluster‐C PDs. The following step is a randomized controlled trial to further document the (cost‐)effectiveness of GST.