Autism Transition to Adulthood Groups (ATAG): protocol for a feasibility RCT of a new peer-group intervention to promote successful transition to adulthood for autistic young people.

introductionAutism is a lifelong neurodevelopmental condition diagnosed on the basis of differences in social communication, interaction and repetitive behaviours, including sensory sensitivities. Autistic individuals without intellectual disabilities often face barriers to positive adult outcomes and are at high risk for poor health, including mental health issues, which could be mitigated by improving well-being. Young people should receive support to increase their well-being during the transition to adulthood, when social and family support often reduces. This is the protocol for a feasibility randomised controlled trial (RCT) of an online peer-group intervention, 'Understanding You, Discovering You' (UYDY). Objectives included assessing recruitment and retention rates, acceptability of procedures, characterising usual care, assessing the acceptability of UYDY and care as usual (CAU) and calculating outcome measure variances for a full trial. METHODS AND ANALYSIS: This two-arm parallel feasibility RCT includes a nested qualitative evaluation. Seventy participants aged 16-25 years old with a clinical autism diagnosis will be randomised on a 1:1 basis to UYDY or CAU. Exclusion criteria include risk of harm to self or others, receipt of postdiagnostic support in the past 12 months, and literacy levels such that the written session materials are not accessible. UYDY, a 6-week online peer-group intervention, will cover topics such as understanding autism, problem-solving and accessing services, and is facilitated by an autistic person and social care professionals. The main outcomes from the feasibility trial will be collecting data on (1) recruitment and retention rates; (2) the acceptability of randomisation and outcome measurement procedures; (3) CAU accessed by participants; (4) acceptability of the interventions; (5) clinical outcome measure variances (see below). See the Statistical methods section below for how this will be assessed in the current study. Clinical outcomes will be measured at baseline, and 8, 16 and 24 weeks post-randomisation. The primary clinical outcome is well-being, assessed using the Warwick Edinburgh Mental Wellbeing Scale. Secondary clinical outcomes include autism social identification, quality of life, social support and loneliness. Adverse events will be monitored and reported. Carer impact will also be measured. Participants will be recruited from England and Wales via charities and NHS services. Qualitative interviews will be conducted to explore the acceptability of trial participation including randomisation and the interventions. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the HRA and NHS REC (23/WA/0113). Informed consent will be collected from all participants (see online supplemental material for an example consent form). Results will inform the design of a full RCT and will be disseminated through peer-reviewed journals, conferences, and stakeholder events. TRIAL REGISTRATION NUMBER: ISRCTN10513626.