LINA Study 1: Concept Development of a Guideline-Oriented Intensive Outpatient Transition Program for Anorexia Nervosa

Anorexia nervosa (AN) is a severe mental disorder with substantial morbidity, elevated mortality, and frequent onset during adolescence (Arcelus et al., 2011; Treasure et al., 2020). For many affected individuals, the course of illness extends into young adulthood, when developmental tasks such as autonomy, educational or occupational transitions, changes in living situation, and reorganization of family involvement coincide with changes in the mental health care system. The transition from child and adolescent mental health services (CAMHS) to adult mental health care is therefore a clinically sensitive period. Research on mental health transitions indicates that young people may experience discontinuity of care, unclear responsibilities, loss of established therapeutic relationships, and difficulties accessing adult services (Singh et al., 2010; Paul et al., 2015). For AN, these challenges are particularly relevant because relapse prevention, weight stabilization, motivation for treatment, and continuity of multidisciplinary care are central to long-term recovery (NICE, 2017; Herpertz et al., 2019). Current clinical guidelines emphasize multimodal, coordinated, and continuous care for eating disorders, including psychological treatment, medical monitoring, nutritional support, and involvement of caregivers where appropriate (Herpertz et al., 2019; NICE, 2017). In the German care context, the S3 guideline for eating disorders will serve as the primary disorder-specific reference (Herpertz et al., 2019); NICE NG69 will be used as an additional international reference (NICE, 2017). In addition, the German S3 guideline on transition from pediatric to adult medicine highlights the need for planned, coordinated, and individualized transition processes to ensure uninterrupted care (Gesellschaft für Transitionsmedizin, 2021). The present preregistration concerns the concept-development study within the LINA project. LINA stands for “Leitlinienorientiertes Intensivprogramm Anorexia nervosa” [Guideline-Oriented Intensive Outpatient Program for Anorexia Nervosa]. The aim is to develop a structured, manualized outpatient intensive program for patients with AN in the transition to adult care. The program is conceptually informed by the Bielefeld Intensive Outpatient Program for Depression (BID), an established multimodal short-term outpatient treatment model in adult psychiatry that combines psychotherapy, psychiatric monitoring, group-based components, exercise-related elements, and social work support (Driessen et al., 2019). The present study does not test feasibility or effectiveness of LINA modules. Instead, it identifies transition-related needs, integrates patient, parent/caregiver, clinician, guideline, literature, and BID-transfer perspectives, and prepares a preliminary manual for later evaluation.