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Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12625001199404
Ethics application status
Help: Ethics application status
Approved
Date submitted
Help: Date submitted
4/08/2025
Date registered
Help: Date registered
31/10/2025
Date last updated
Help: Date last updated
31/10/2025
Date data sharing statement initially provided
Help: Data sharing statement date
31/10/2025
Type of registration
Help: Type of registration
Retrospectively registered

Titles & IDs
Public title
A study comparing a new group cognitive behavioural therapy (CBT) to standard dialectical behaviour therapy (DBT) in adults with binge eating disorder
Scientific title
A Quasi-Experimental Study comparing a novel group cognitive behavioural therapy intervention with standard group dialectical behaviour therapy for binge eating disorder in adults
Additional trial identifiers [1] 315064 0
Nil Known
Universal Trial Number (UTN)
Trial acronym
Related trial records

Health condition
Health condition(s) studied:
Binge eating disorder 338443 0
Condition category
Condition code
Mental Health 334739 334739 0 0
Eating disorders

Intervention/exposure
Study type
Interventional
Description of the intervention or exposure
Group Cognitive Behavioural Therapy (CBT) Intervention – Experimental Arm
Participants assigned to the experimental arm will receive a novel group cognitive behavioural therapy (CBT) program specifically developed for the treatment of Binge Eating Disorder (BED). The intervention consists of 20 weekly 2-hour group sessions and includes six modules:
1. Psychoeducation on BED and emotional eating
2. Training in mindfulness and self-observation skills
3. Self-regulation strategies, including management of environmental triggers, identification and restructuring of dysfunctional thoughts, and emotion regulation
4. Reduction of self-criticism and development of self-compassion
5. Improvement of interpersonal functioning and assertiveness
6. Relapse prevention and maintenance planning
Each therapy group will include approximately 8 participants. The intervention is based on cognitive-behavioural principles and integrates elements from third-wave CBT, including mindfulness and values-based action. Sessions will be delivered at the outpatient clinic of Aiginiteio Hospital in Athens, Greece. The intervention will be administered by licensed psychologists trained in cognitive behavioural therapy and CBT for eating disorders. Therapists will adhere to a structured manual specifically developed for this protocol, ensuring consistency across groups.
Allocation procedure
Participants are assigned to one of the two intervention arms (CBT or DBT) using an alternating allocation procedure. After identifying a cohort of approximately 16 eligible participants, individuals are allocated alternately to each treatment arm (first to Group A, second to Group B, etc.). The labelling of the groups (CBT or DBT) is alternated with each new cohort to reduce systematic bias. Allocation is performed by the researcher conducting eligibility screening, based on order of recruitment. This procedure is non-randomised, and full allocation concealment is not applied.
Intervention code [1] 331674 0
Behaviour
Intervention code [2] 331675 0
Treatment: Other
Description of the comparator or control
Group Dialectical Behaviour Therapy (DBT) Intervention – Comparison Arm
Participants assigned to the comparison arm will receive a standard group dialectical behaviour therapy (DBT) program for BED. The DBT protocol (Safer, Telch & Chen, 2009), which has been adapted and validated for the Greek population, consists of 20 weekly 2-hour group sessions and includes three core skills modules:
1. Mindfulness
2. Emotion regulation
3. Distress tolerance
Each therapy group will include approximately 8 participants. The intervention will be delivered at the outpatient clinic of Aiginiteio Hospital in Athens, Greece, by licensed psychologists who have been trained in dialectical behaviour therapy and in the adapted DBT protocol for BED. Therapists will follow a structured treatment manual to ensure fidelity and consistency across groups.
Allocation procedure
Participants are assigned to one of the two intervention arms (CBT or DBT) using an alternating allocation procedure. After identifying a cohort of approximately 16 eligible participants, individuals are allocated alternately to each treatment arm (first to Group A, second to Group B, etc.). The labelling of the groups (CBT or DBT) is alternated with each new cohort to reduce systematic bias. Allocation is performed by the researcher conducting eligibility screening, based on order of recruitment. This procedure is non-randomised, and full allocation concealment is not applied.
Control group
Active

Outcomes
Primary outcome [1] 342388 0
Change in binge eating symptom severity
Timepoint [1] 342388 0
T1: Baseline (before intervention) T2: Mid-treatment (Session 10) T3: Post-treatment (Session 20) T4: 3-month follow-up (after treatment – primary timepoint) T5: 12-month post-intervention completion (only for the experimental CBT group)
Primary outcome [2] 342729 0
Change in perceived loss of control over eating
Timepoint [2] 342729 0
T1: Baseline (before intervention) T2: Mid-treatment (Session 10) T3: Post-treatment (Session 20) T4: 3-month follow-up (after treatment – primary timepoint) T5: 12-month post-intervention completion (only for the experimental CBT group)
Primary outcome [3] 342730 0
Change in emotional eating behaviour
Timepoint [3] 342730 0
T1: Baseline (before intervention) T2: Mid-treatment (Session 10) T3: Post-treatment (Session 20) T4: 3-month follow-up (after treatment – primary timepoint) T5: 12-month post-intervention completion (only for the experimental CBT group)
Secondary outcome [1] 450655 0
Change in food craving (primary outcome)
Timepoint [1] 450655 0
T1: Baseline (before intervention) T2: Mid-treatment (Session 10) T3: Post-treatment (Session 20) T4: 3-month follow-up (after treatment) T5: 12-month post-intervention completion (only for the experimental CBT group)
Secondary outcome [2] 451935 0
Change in depression, anxiety, and stress symptoms
Timepoint [2] 451935 0
T1: Baseline (before intervention) T2: Mid-treatment (Session 10) T3: Post-treatment (Session 20) T4: 3-month follow-up (after treatment) T5: 12-month post-intervention completion (only for the experimental CBT group)
Secondary outcome [3] 451936 0
Change in quality of life (overall and domain-specific: physical, psychological, social relationships)
Timepoint [3] 451936 0
T1: Baseline (before intervention) T2: Mid-treatment (Session 10) T3: Post-treatment (Session 20) T4: 3-month follow-up (after treatment) T5: 12-month post-intervention completion (only for the experimental CBT group)
Secondary outcome [4] 453789 0
Change in participants' self-esteem scores at post-intervention compared to baseline.
Timepoint [4] 453789 0
T1: Baseline (before intervention) T2: Mid-treatment (Session 10) T3: Post-treatment (Session 20) T4: 3-month follow-up (after treatment) T5: 12-month post-intervention completion (only for the experimental CBT group)

Eligibility
Key inclusion criteria
Adults diagnosed with Binge Eating Disorder (BED) according to DSM-5 criteria.
Minimum age
18 Years
Maximum age
70 Years
Sex
Both males and females
Healthy volunteers
No
Key exclusion criteria
Individuals presenting with severe depression (defined as moderate to severe Major Depressive Disorder with psychotic features), psychotic disorders, substance use disorders, current engagement in psychotherapy, pregnancy, or a diagnosed personality disorder. Mild or remitted depression, as well as the use of antidepressant medication, will not constitute exclusion criteria.

Study design
Purpose of the study
Treatment
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
Statistical Analysis
Descriptive statistics will be used to summarize study variables. For categorical variables, absolute and relative frequencies (%) will be reported, along with 95% confidence intervals and appropriate graphical representations (e.g., bar charts). For continuous variables, descriptive measures will include means, standard deviations, medians, interquartile ranges (25th–75th percentiles), and minimum and maximum values. The distribution of continuous data will also be illustrated using histograms and box plots. Normality of distribution will be assessed using the Kolmogorov–Smirnov and Shapiro–Wilk tests. To compare primary outcomes (Binge Eating Scale, Emotional Eating Scale, and Food Craving Questionnaire–Trait), as well as secondary outcomes (quality of life, self-esteem, symptoms of depression, anxiety, and stress) over time and between the two study groups, generalized linear models (GLMs) for repeated measures will be employed. Bonferroni correction will be applied to control for Type I error in the context of multiple comparisons.All statistical tests will be two-tailed, and statistical significance will be set at p < 0.05. Analyses will be conducted using IBM SPSS Statistics, version 26.0.

Sample Size and Power Analysis
A power analysis was conducted for a repeated-measures design with three timepoints to test the primary hypothesis: improvements in scores on the Binge Eating Scale, the Emotional Eating Scale, and the Food Craving Questionnaire–Trait. A sample size of 45 participants provides 95% power to detect within-subject effects with an effect size (Cohen’s f) of 0.22 or greater. To account for potential attrition, the sample size will be increased to 50 participants.
A separate power analysis was conducted for a mixed-design ANOVA with two study groups and three measurement points over time. This analysis supports the detection of:
• Between-group differences at a single time point with 95% power for an effect size of 0.30,
• Within-group changes across two time points with 95% power for an effect size of 0.17,
• Group × time interaction effects with 95% power for an effect size of 0.17.
The planned total sample size for the full trial is 90 participants (45 per group), which will be increased to 100 (50 per group) to account for potential dropout during the intervention.
Given the non-randomised allocation, baseline comparability between groups will be examined. If meaningful imbalances are present, baseline covariates will be included in the models to adjust for potential confounding. In addition, because participants are nested within therapy groups, potential clustering effects will be examined and, if necessary, multilevel modelling will be applied.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
4/10/2024
Date of last participant enrolment
Anticipated
1/10/2027
Actual
Date of last data collection
Anticipated
7/04/2028
Actual
Sample size
Target
100
Accrual to date
24
Final
Recruitment outside Australia
Country [1] 27268 0
Greece
State/province [1] 27268 0

Funding & Sponsors
Funding source category [1] 319631 0
Self funded/Unfunded
Name [1] 319631 0
Athanasia Mavroeidi, psychologist, M.Sc, Medical School, National and Kapodistrian University of Athens
Country [1] 319631 0
Greece
Primary sponsor type
University
Name
Medical School - National and Kapodistrian University of Athens
Address
Country
Greece
Secondary sponsor category [1] 322134 0
None
Name [1] 322134 0
Address [1] 322134 0
Country [1] 322134 0
Other collaborator category [1] 283615 0
University
Name [1] 283615 0
Dr Fragiskos Gonidakis, Medical School - National and Kapodistrian University of Athens
Address [1] 283615 0
Country [1] 283615 0
Greece

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 318192 0
Ethics committee, Medical school, National and Kapodistrian University of Athens
Ethics committee address [1] 318192 0
Ethics committee country [1] 318192 0
Greece
Date submitted for ethics approval [1] 318192 0
19/04/2024
Approval date [1] 318192 0
24/05/2024
Ethics approval number [1] 318192 0
874

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 143402 0
Ms Athanasia Mavroeidi
Address 143402 0
Medical School, National and Kapodistrian University of Athens, Mikras Asias 15, Athens, 11527
Country 143402 0
Greece
Phone 143402 0
+306937647218
Fax 143402 0
Email 143402 0
[email protected]
Contact person for public queries
Name 143403 0
Athanasia Mavroeidi
Address 143403 0
Medical School, National and Kapodistrian University of Athens, Mikras Asias 15, Athens, 11527
Country 143403 0
Greece
Phone 143403 0
+306937647218
Fax 143403 0
Email 143403 0
[email protected]
Contact person for scientific queries
Name 143404 0
Athanasia Mavroeidi
Address 143404 0
Medical School, National and Kapodistrian University of Athens, Mikras Asias 15, Athens, 11527
Country 143404 0
Greece
Phone 143404 0
+306937647218
Fax 143404 0
Email 143404 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No
No IPD sharing reason/comment: This is a self-funded PhD study involving sensitive clinical and psychometric data. No provision for individual participant data sharing is included in the study protocol, and participant consent for data sharing has not been obtained. Additionally, ethical and data protection considerations, including compliance with GDPR, limit the ability to share de-identified individual data.



What supporting documents are/will be available?

TypeCitationLinkEmailOther DetailsAttachment
Study protocol    Study protocol.docx


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
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