Step by Step Group Therapy for Bulimia Nervosa: Effectiveness and Mechanisms of Change.

Study Overview
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Brief Summary
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This a pseudo-randomized clinical trial that examines if a specific group therapy for BN is effective in improving its symptomatology, and what variables mediate such improvements. To do so a sample of 100 patients with BN will be pseudorandomized in a Group Therapy for BN or in a control waiting list group. Patients will be assessed at baseline, at the end of the group therapy and at 2 year follow up.

Detailed Description
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This is a controlled non randomized study that will compare a group of patients with BN that participate in the SBS group therapy with a group of BN patients who will be in wait list as a control condition. Patients for this single center trial will be recruited from the outpatient facility of the Hospital de la Santa Creu I Sant Pau (Barcelona, Spain). After assessed for eligibility participants will be given a set of self -report questionnaires. After the questionnaires are completed participants will be allocated to wait list condition or to the treatment arm. Time between assessment and starting the SBS group will be a month or least. Participants will be administered the same questionnaires the following month after finishing the treatment or after 3 to 4 months after the first assessment for the control condition.

Official Title
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Step by Step Group Therapy for Bulimia Nervosa: Effectiveness and Mechanisms of Change.

Conditions
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Bulimia Nervosa

Intervention / Treatment
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* Behavioral: l Group Therapy for BN.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnostic of Bulimia Nervosa Exclusion Criteria: Not understanding Spanish or Catalan Language

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: BN Group<br>Patients will take part of a Therapeutic BN Group | Behavioral: l Group Therapy for BN.<br>* 9 to 10 group sessions of 90 to 120min each<br>|
| No Intervention: Waiting List<br>Participants will be in the waiting list. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Eating Attitudes Test, E-40. | A self report questionarie that assesses eating disorder symptomatology. The range of scores is 0-78. Higher scores mean higher eating disorders sympthoms. | 3 months | 
| Eating Disorder Inventory, EDI | A self report questionarie that assesses eating disorder symptomatology. The range of scores is 0-192. Higher scores mean higher eating disorders sympthoms | 3 months | 
| Bulimic Investigatory Test Edinburgh, BITE | A self report questionarie that assesses bulimia nervosa symptomatology.The range of scores is 0-30. Higher scores mean higher bulimic sympthoms | 3 months | 
| Body Shape Questionnaire, BSQ-34 | A self report questionarie that assesses eating disorder symptomatology. The score is ranging between 34-204 points. Higher scores point to an increased level of concern on body shape. | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Working alliance Inventory -short, WAIS. | A self report questionarie that assesses bulimia nervosa symptomatology. Values range from 12 to 84. Hihger scores meaning higher therapeutic alliance. | 3 months | 
| Autism-Spectrum Quotient, AQ | A self report questionarie that assesses autistic traits. The range of scores is 0 to 50. Higher scores mean higher autistic traits. | 3 months | 
| Quality of Life Enjoyment and Satisfaction Questionnaire, Q-LES-Q. | A self report questionarie that assesses quality of life. The range of scores is 0-100. Higher scores mean higher quality of life. | 3 months | 
| Beck Depression Inventory, BDI-II | A self report questionarie that assesses depressive symptoatology. The range of scores is 0-83. Higher scores mean higher depressive symptoms. | 3 months | 
| Rosenberg Self-Esteem Scale, RSE. | A self report questionarie that assesses self steem. The scale ranges from 0-30. Higher scores mean higher self-esteem. The range scores is 0-60. | 3 months | 
| State -Trait Anxiety Inventory, STAI. | A self report questionarie that assesses anxiety. Higher scores mean higher anxiety. | 3 months | 
| Difficulties in Emotion Regulation Scale (DERS). | A self report questionarie that assesses emotion regulation difficulties. The scale ranges from 28-40. H igher scores indicate more difficulty in emotion regulation. | 3 months |