HALO-TRIAL: High, Medium And LOw Intensity Psychotherapy for Binge Eating Disorder

The HALO trial is a investigator-initiated, four-arm, partially blinded, randomized controlled superiority trial evaluating the effectiveness of three formats and intensities of Cognitive Behavioral Therapy-Enhanced (CBT-E) compared with manualized treatment as usual (TAU) for adults with Binge Eating Disorder (BED).

BED is associated with substantial psychiatric and physical morbidity, and despite psychotherapy being the recommended first-line treatment, there is limited high-quality evidence directly comparing different CBT-E delivery formats compared with an active control intervention. The trial aims to determine whether individual CBT-E provides superior clinical outcomes compared with group CBT-E, CBT-E guided self-help, and manualized TAU.

A total of 256 participants with a primary diagnosis of BED will be recruited through Danish Mental Health Services and public advertisement. Following informed consent and baseline diagnostic assessments, eligible participants will be randomized in a 1:1:1:1 ratio to one of four treatment arms: (1) individual CBT-E, (2) group CBT-E, (3) therapist-guided CBT-E self-help, or (4) manualized group-based systemic narrative therapy delivered as treatment as usual. All interventions are delivered over a 21-week treatment period.

Diagnostic assessments include the Eating Disorder Examination interview to confirm the diagnosis of BED and the Mini International Neuropsychiatric Interview to assess psychiatric comorbidity and study eligibility. The primary outcome is change in binge eating frequency measured using the Eating Disorder Examination Questionnaire. Secondary outcomes include remission from BED assessed by the Eating Disorder Examination interview, overall eating disorder psychopathology (Eating Disorder Examination Questionnaire), psychological well-being (World Health Organization-Five Well-Being Index), work and social functioning (Work and Social Adjustment Scale), anxiety symptoms (State-Trait Anxiety Inventory), and depressive symptoms (Beck Depression Inventory-II).

In addition, a broad range of exploratory psychological, clinical, and psychosocial measures will be collected to investigate potential mechanisms of treatment response, predictors of outcome, and moderators and mediators of treatment effects (list of exploratory outcomes is available upon request). These exploratory measures are used only for hypothesis-generating and are not part of the primary efficacy analyses. Post-treatment diagnostic interviews are conducted by blinded outcome assessors. Due to the nature of the psychotherapeutic interventions, participants and therapists cannot be blinded to treatment allocation. Outcome assessors, statisticians, investigators responsible for data analysis, and the trial leadership remain blinded until completion of the primary analyses.