**Investigation of Multi-Family Therapy for Anorexia Nervosa** This study looks at how multi-family therapy (MFT) can help treat anorexia nervosa. Anorexia nervosa is an eating disorder where people eat very little because they are worried about gaining weight. MFT means that families of patients with anorexia nervosa join together to learn how to support their loved ones better. Families will either meet in person or online to learn about eating disorders, share experiences, and practice skills to help their children. The study will see if this therapy helps with things like weight, emotions, and eating disorder symptoms. **Key Points:** - The study includes a 4-day intensive therapy session with follow-up meetings over a year. - Families will participate in group activities, with some sessions online and some in person. - Participants must be 11-18 years old, living with a parent, and medically stable. Families will learn about the illness, support each other during meals, and work on improving family relationships. The goal is to create a supportive community and help families manage the challenges of anorexia nervosa.