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.

Inclusion Criteria:

• Diagnostic of Bulimia Nervosa

Exclusion Criteria:

• Not understanding Spanish or Catalan Language