Work

Quest for optimal treatment of cluster-C personality disorders: evaluating schema therapy formats in a multicentre randomised controlled trial

Year: 2026

Type: article

Study designs: Randomized Controlled Trial, Clinical Trial

Abstract: Background Schema therapy (ST) is proven to be effective for cluster-C personality disorders (PDs). Recently, a group format of ST (GST) has gained popularity but has not been compared with other treatments.Objective To compare the effectiveness of GST to individual ST (IST) and specialised treatment as usual (sTAU) for cluster-C PDs.Method We conducted a multicentre parallel-group, randomised controlled trial (QUalitative and Effectiveness Study to select optimal Treatment for Cluster-C PD) comparing 1 year of GST and IST with open-ended sTAU, with a follow-up assessment 2 years after start of treatment. Outpatients (>18 years) with a primary cluster-C PD were recruited and assigned to GST (30 weekly sessions plus 4 monthly booster sessions), IST (50 sessions with decreasing frequency) or sTAU (routine care in PD-specialised departments). The primary outcome was cluster-C PD severity change.Results 369 participants (mean (SD) age, 37.24 (11.21) years; 242 (65.6) female) received GST (46.6%), IST (26.0%) or sTAU (27.4%). At 1 year, GST was superior to sTAU (d=0.33, 95% CI 0.05 to 0.61, p=0.02), and IST was superior to sTAU (d=0.41, 95% CI 0.10 to 0.72, p=0.010). GST and IST did not differ significantly (d=0.08, 95% CI −0.19 to 0.35, p=0.57). No significant differences were found at 2 years (GST-sTAU: d=0.12, 95% CI −0.18 to 0.42, p=0.44; GST-IST: d=0.11, 95% CI −0.18 to 0.39, p=0.46; IST-sTAU: d=0.23, 95% CI −0.11 to 0.56, p=0.18). Treatment retention in IST (92.7%) was superior to sTAU (78.2%) but did not differ significantly with GST (84.9%) at 1 year. At 2 years, treatment retention in IST and GST remained the same and was both superior to sTAU (72.3%).Conclusion Both GST and IST outperformed sTAU after 1 year, although differences were no longer evident at follow-up. GST and IST showed higher retention rates than sTAU.Clinical implications These findings support GST and IST as good treatment options for cluster-C PDs.Trial registration number NL-OMON19942.

Source: BMJ Mental Health

DOI: 10.1136/bmjment-2026-302929