Metacognitive Interpersonal Therapy Across Transdiagnostic Eating Disorders, Including Underweight

The goal of this clinical trial is to assess if Metacognitive Interpersonal Therapy for Eating Disorders (MIT-ED) is effective for treating various forms of Eating Disorders (ED) and reducing dropout rates. The trial will also evaluate its feasibility and outcomes in a patient group including also underweight participants. The main questions it aims to answer are:

* Does MIT-ED improve eating disorder symptoms and reduce overall maintenance factors, as alexithymia, emotional dysregulation, maladaptive perfectionism, and self-esteem?
* Is MIT-ED effective in reducing the severity of personality disorders and associated global psychiatric symptoms?
* What are the dropout rates and adherence levels for patients receiving MIT-ED?

Participants will:

* Undergo an initial screening to confirm eligibility, including a comprehensive clinical interview and assessments based on inclusion and exclusion criteria for the study.
* Receive up to 40 individual sessions of MIT-ED, each lasting 50-60 minutes, over a period of approximately 10-12 months.
* Attend regular assessment focusing on eating disorder symptoms (Eating Disorder Examination Questionnaire, EDE-Q 6.0, and ED Interview, EDE), emotional dysregulation (Difficulties in Emotion Regulation Scale, DERS), alexithymia (Toronto Alexithymia Scale-20, TAS-20), and self-esteem (Rosenberg Self-Esteem Scale, RSES). Assessment will be conducted at baseline (before starting MIT-ED sessions), after 20 MIT-ED sessions (approximately after 5 months), post-treatment (approximately after 10 months), and at 3 months follow-up. A longer 12-months follow-up is planned.

Researchers will evaluate the effectiveness of MIT-ED based on treatment adherence, symptom improvement, and the reduction of maintenance mechanisms associated with Eating Disorders. Positive results could support the design of a larger, controlled Randomized Clinical Trial (RCT).

This is a single arm study. The hypotheses are that Metacognitive Interpersonal Therapy for Eating Disorders (MIT-ED) will be able to keep drop-out lower than possible, estimated \<20%; promote remission in the primary Eating Disorder (ED) measure; achieve weight gain in underweight participants.

Recruitment will stop once 64 participants have met inclusion criteria and have accepted to participate to the study. The study will recruit adults aged 18 and over, diagnosed with an ED within the past six months, from the Centro di Trattamento Integrato - Disturbi Alimentari e Obesità (CTI-Disturbi Alimentari e Obesità) in Verona and Genova. Underweight individuals will be included to evaluate MIT-ED's broader applicability.

Participants will receive up to 40 individual sessions of MIT-ED, delivered either in-person or via videoconferencing by 3 trained therapists. Therapists will receive 2 hours supervision every two weeks with 2 of Metacognitive Interpersonal Therapy designers. Therapy sessions will be randomly audio-recorded for process analysis Assessments will occur at baseline, after 20 MIT-ED sessions (approximately after 5 months), post-treatment (approximately after 10 months), and at 3 months follow-up, where publications of the results are scheduled. A longer term 12-months follow-up is planned. A research assistant will handle psychometric test administration and coordination with the clinical team.

This study will provide preliminary evidence on the feasibility and effectiveness of MIT-ED in a broader ED population, including underweight patients. The results will inform the design of a larger controlled trials to further validate MIT-ED efficacy with the hope it results as a new treatment option for patients with transdiagnostic ED.

Eligibility Criteria:
Inclusion Criteria:

* Adult outpatients (from age 18 years)
* Having an Eating Disorder for which they required treatment
* BMI between 17.5 and 40
* Provision of informed consent

Exclusion Criteria:

* Receiving ongoing psychiatric, other psychotherapeutic treatment
* Coexisting psychiatric disorders precludeing eating disorder-focused treatment or that requires specialized treatment: bipolar I, psychosis, alcohol or substance abuse, suicidality. PTSD is an exclusion criteria as long as its symptoms as prominent so to require a specialized empirically supported treatment
* Intellectual disability