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

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.

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.

A self report questionarie that assesses eating disorder symptomatology. The range of scores is 0-78. Higher scores mean higher eating disorders sympthoms.

A self report questionarie that assesses eating disorder symptomatology. The range of scores is 0-192. Higher scores mean higher eating disorders sympthoms

A self report questionarie that assesses bulimia nervosa symptomatology.The range of scores is 0-30. Higher scores mean higher bulimic sympthoms

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.

A self report questionarie that assesses bulimia nervosa symptomatology. Values range from 12 to 84. Hihger scores meaning higher therapeutic alliance.

A self report questionarie that assesses autistic traits. The range of scores is 0 to 50. Higher scores mean higher autistic traits.

A self report questionarie that assesses quality of life. The range of scores is 0-100. Higher scores mean higher quality of life.

A self report questionarie that assesses depressive symptoatology. The range of scores is 0-83. Higher scores mean higher depressive symptoms.

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.

A self report questionarie that assesses emotion regulation difficulties. The scale ranges from 28-40. H igher scores indicate more difficulty in emotion regulation.

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

Agh T, Kovacs G, Supina D, Pawaskar M, Herman BK, Voko Z, Sheehan DV. A systematic review of the health-related quality of life and economic burdens of anorexia nervosa, bulimia nervosa, and binge eating disorder. Eat Weight Disord. 2016 Sep;21(3):353-364. doi: 10.1007/s40519-016-0264-x. Epub 2016 Mar 4.

- Andrade-González, N., & Fernández-Liria, A. (2016). Spanish adaptation of the working alliance inventory-short (WAI-S). Current Psychology, 35(1), 169-177.

Fairburn CG, Bailey-Straebler S, Basden S, Doll HA, Jones R, Murphy R, O'Connor ME, Cooper Z. A transdiagnostic comparison of enhanced cognitive behaviour therapy (CBT-E) and interpersonal psychotherapy in the treatment of eating disorders. Behav Res Ther. 2015 Jul;70:64-71. doi: 10.1016/j.brat.2015.04.010. Epub 2015 Apr 22.

Hay P. A systematic review of evidence for psychological treatments in eating disorders: 2005-2012. Int J Eat Disord. 2013 Jul;46(5):462-9. doi: 10.1002/eat.22103.

Polnay A, James VA, Hodges L, Murray GD, Munro C, Lawrie SM. Group therapy for people with bulimia nervosa: systematic review and meta-analysis. Psychol Med. 2014 Aug;44(11):2241-54. doi: 10.1017/S0033291713002791. Epub 2013 Nov 15.