Anorexia Nervosa (AN) has the highest mortality rate compared to any other psychiatric disorder. The most promising treatment for adolescents with AN is family-based treatment (FBT). However, only 50% of patients receiving FBT fully remit at 12-month follow-up. Consequently, providing an alternative therapy early in the treatment course for those not responding to FBT may enhance overall outcome. This study aims to develop a new treatment - Intensive Family-Focused Treatment (IFT) - to improve outcomes in those adolescents, aged 12-18 years, who do not show an early response to FBT.