1 Introduction Adolescent anorexia nervosa (AN) is a severely life-threatening psychiatric illness, associated with among the highest mortality rates of any mental disorder and profound medical, psychological, and social sequelae (Arcelus et al. 2011). Family-based treatment (FBT) is the recommended first-line intervention for the outpatient treatment of AN in New Zealand (NZ), underpinned by extensive international evidence (Benedictson et al. 2025; Datta et al. 2023; Fisher et al. 2019; Hay et al.
