Clinical and Cost-effectiveness of Group Schema Therapy for Complex Eating Disorders: the GST-EAT Study

Overview

Amongst psychiatric illnesses, eating disorders (EDs) are notoriously difficult to treat and have a high mortality rate. The average duration of an ED is 6 years and for a majority of ED patients, the disorder will become chronic. Comorbid personality pathology such as negative core beliefs and early maladaptive schemas (EMS) are strongly related to ED severity and chronicity. Enhanced cognitive-behavioural therapy for eating disorders (CBT-E) is used as the first line transdiagnostic treatment for EDs. However, CBT-E is mainly symptom-focused and does not tap into these underlying core beliefs and EMS. Given the limited treatment effects of existing ED treatments, and the importance of comorbid personality pathology, there is an urgent need to examine more effective treatments for EDs. Group-schematherapy (GST) overcomes the limitations of CBT-E and preliminary results for treatment-resistant EDs are promising. However, robust evidence regarding the clinical and cost-effectiveness of GST for patients that do not benefit from CBT-E is not yet available. The central aim of this project is to investigate the clinical and cost-effectiveness of GST for EDs in patients with comorbid personality pathology, who do not show a clinically significant response in the first phase of CBT-E. This is relevant and important as studies examining the effectiveness of GST for EDs are scarce. This project is a joint research initiative of three academic centers (Dutch Universities), four large nation-wide mental health organizations, and two foundations for client empowerment and participation. Eligible patients will be randomized to either GST or continuation of their CBT-E treatment after failing to show a significant treatment response in the first phase of CBT-E. Based on encouraging findings from previous studies and our own pilot data, a statistically and clinically significant better outcome in terms of ED symptoms, negative core beliefs, EMS, schema modes, and quality of life is expected in the GST group compared to the CBT-E group. GST is also expected to be more cost-effective compared to CBT-E as GST may in the long run prevent chronicity in terms of long treatment trajectories and delayed recovery. Finally, with the proviso of good results for GST, we will disseminate and implement GST in the standard of care for EDs. This project thereby has great potential to improve clinical and cost-effectiveness of treatment for chronic EDs.

Interventions

• Behavioral GST
  Outpatient eating disorder treatment (5 individual pre-group sessions followed by 26 weekly group sessions + 8 optional individual sessions)
• Behavioral CBT-E
  Outpatient eating disorder treatment (20-40 weekly individual sessions)

Primary outcome measures

• Change in Eating Disorder Examination Questionnaire (EDE-Q) score [Time frame: Baseline (Before start CBT-E), 4 weeks (8 sessions CBT-E), end of treatment (up to 39 weeks after randomization), and 6 and 12 months after end of treatment]

Secondary outcome measures (10)

• Childhood Trauma Questionnaire-Short Form (CTQ-SF) [Time frame: Baseline (Before start CBT-E)]
• Change in Young Schema Questionnaire Short Form version 3 3 (YSQ-S3) score [Time frame: Baseline (Before start CBT-E), end of treatment (up to 39 weeks after randomization), and 6 and 12 months after end of treatment]
• Change in Schema Mode Inventory for Eating Disorders (SMI-ED) score [Time frame: 4 weeks (8 sessions CBT-E), end of treatment (up to 39 weeks after randomization), and 6 and 12 months after end of treatment]
• Change in Brief Symptom Inventory (BSI) score [Time frame: 4 weeks (8 sessions CBT-E), end of treatment (up to 39 weeks after randomization), and 6 and 12 months after end of treatment]
• Change in Eating Disorder Quality of Life (EDQoL) score [Time frame: 4 weeks (8 sessions CBT-E), end of treatment (up to 39 weeks after randomization), and 6 and 12 months after end of treatment]
• Clinical Perfectionism Questionnaire (CPQ) [Time frame: Baseline (Before start CBT-E)]
• Session Rating Scale (SRS) [Time frame: up to 39 weeks]
• Quality of life and achievement personalized treatment goals [Time frame: End of treatment (up to 39 weeks after randomization)]
• Treatment Inventory of Costs in Patients with psychiatric disorders (TiC-P) [Time frame: 4 weeks (8 sessions CBT-E), end of treatment (up to 39 weeks after randomization), and 6 and 12 months after end of treatment]
• Change in Quality-adjusted life years score [Time frame: 4 weeks (8 sessions CBT-E), end of treatment (up to 39 weeks after randomization), and 6 and 12 months after end of treatment]

Eligibility criteria

Inclusion criteria

• 1\) age > 16 years;
• 2\) a DSM-5 diagnosis of anorexia nervosa, bulimia nervosa, or other specified ED (atypical anorexia nervosa or bulimia nervosa with a low frequency or limited duration).

Exclusion criteria

• 1\) not being able to speak and read the Dutch language;
• 2\) being in an acute psychotic mental health state at the start of the study;
• 3\) being diagnosed with an autism spectrum disorder;
• 4\) having an IQ below 80, as determined with a validated instrument;
• 5\) showing an early response after phase 1 of CBT-E.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

Netherlands · 7 centers

• GGz Breburg — Breda
• Accare — Groningen
• GGZ Friesland — Leeuwarden
• GGNet Amarum — Nijmegen
• GGz Breburg — Tilburg
• Co-eur — Utrecht
• GGNet Amarum — Warnsveld

Publications

• Mares SHW, Roelofs J, Zinzen J, Beatse M, Elgersma HJ, Drost RMWA, Evers SMAA, Elburg AAV. Clinical effectiveness, cost-effectiveness and process evaluation of group schema therapy for eating disorders: study protocol for a multicenter randomized controlled trial. BMC Psychol. 2024 Mar 4;12(1):123. doi: 10.1186/s40359-024-01624-w. PMID 38439092

Identifiers

NCT: NCT05812950 · NL80491.068.22 · 60-63600-98-1131

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗