Authors' objectives: In clinical practice, olanzapine is commonly used in young people with anorexia nervosa, although the underpinning evidence-base is limited. However, its efficacy, tolerability, acceptability and adherence rate, and the patients’, carers’ and clinicians’ views of olanzapine treatment are unclear. This synopsis article summarises the methods and results of the OPEN feasibility study, overarching the findings and drawing comprehensive conclusions from a quantitative feasibility outcome paper and two qualitative research papers.

Authors' results and conclusions: Fifty-two people were pre-screened, 35 were eligible and 20 participants were recruited and started olanzapine. Of these, 15 continued olanzapine for ≥ 16 weeks. Participants experienced, on average, a decrease in their eating disorder psychopathology, and body weight and body mass index increased during treatment with olanzapine as an adjunct to treatment as usual. Important themes derived from semi-structured qualitative interviews with young people and their parents were: moving away from the illness towards recovery, evaluating information on olanzapine, consent and trust in shared decision-making and the ambivalence around recovery. The main themes expressed by clinicians included: acknowledging the concerns of young people with anorexia nervosa and their families, prioritising person-centred care, the limited service capacity and strict study eligibility criteria. A realistic time schedule for site-preparation, recruitment, treatment and follow-up, realistic recruitment targets and easy access to medical and laboratory examinations may improve the success of future feasibility studies and randomised controlled trials in this patient group.

Authors' methods: The OPEN study assessed the feasibility of a future randomised controlled trial on olanzapine in young people with anorexia nervosa in an open-label, one-armed feasibility study. In this study, we aimed to include 55 patients with anorexia nervosa or atypical anorexia nervosa aged 12–24 who gained

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hta/NIHR136176

Year Published: 2026

URL for published report: https://www.journalslibrary.nihr.ac.uk/hta/GJHH0812

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/GJHH0812

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk