A web-based intervention for carers of individuals with anorexia nervosa (We Can): Trial protocol of a randomised controlled trial investigating the effectiveness of different levels of support

Background: Anorexia nervosa (AN) is a life-threatening mental disorder that is associated with substantial caregiver burden. Carers of individuals with AN report high levels of distress and self-blame, and insufficient knowledge to help their loved ones. However, carers can have a very important role to play in aiding recovery from AN, and are often highly motivated to assist in the treatment process. This manuscript presents the protocol for a randomised controlled trial (RCT) of We Can, a web-based intervention for carers for people with AN. The study aims to investigate the effectiveness of We Can delivered with different intensities of support. Methods: The study takes the form of a multi-site, two-country, three group RCT, comparing We Can (a) with clinician messaging support (We Can-Ind), (b) with moderated carer chatroom support (We Can-Chat) and (c) with online forum only (We Can-Forum). Participants will be 303 carers of individuals with AN as well as, where possible, the individuals with AN themselves. Recruitment will be via specialist eating disorder services and carer support services in the UK and Germany. Randomisation of carers to one of the three intervention conditions in a 1:1:1 ratio will be stratified by whether or not the individual with AN has (a) agreed to participate in the study and (b) is a current inpatient. The We Can intervention will be provided to carers online over a period of 12 weeks. Participants will complete self-report questionnaires at pre-intervention (T1), mid-intervention (mediators only; 4-weeks post-randomisation), post-intervention (T2; 3-months post randomisation), and 6 months (T3) and 12 months (T4) after randomisation. The primary outcome variables are carer symptoms of depression and anxiety. Secondary outcome variables will be measured in both carers and individuals with AN. Secondary carer outcome variables will include alcohol and drug use and quality of life, caregiving behaviour, and the acceptability and use of We Can and associated supports. Secondary outcomes measured in individuals with AN will include eating disorder symptoms, and symptoms of depression and anxiety. The study will also evaluate the cost-effectiveness of the three We Can conditions, and test for mediators and moderators of the effects of We Can. The trial is registered at the International Standard Randomisation Controlled Trial Number (ISRCTN) database, registration number: ISRCTN11399850. Discussion: The study will provide insight into the effectiveness of We Can and its optimal method/s of delivery. Keywords: Anorexia nervosa, Carer support, Online interventions, E-treatment, Mental health, ICar