Autism Transition to Adulthood Groups (ATAG)

INTERVENTION: Participants will be randomised across two interventions: (1) Autism Transition to Adulthood Group (ATAG), or (2) Care as usual (CAU). The ATAG intervention involves si Xonline peer‐group sessions in groups of 8‐10 autistic young people with social care and autistic facilitators. The CAU intervention involves receiving the standard care for autistic young people in each participant’s region. The randomisation sequence will be generated by Sealed Envelope TM. Randomisation will be stratified by age (16‐17 or 18‐25). Participants will be randomised to one of two treatment groups on a 1:1 ratio, that is either ATAG (intervention arm) or CAU (control arm). CONDITION: Autism spectrum conditions ; Mental and Behavioural Disorders PRIMARY OUTCOME: Participant impact will be measured using the Warwick‐Edinburgh Mental Wellbeing Scale (WEMWBS) at baseline, 8‐, 16‐ and 24‐ weeks SECONDARY OUTCOME: ; 1. Affiliation with the autistic community will be measured through the Autism Social Identification Scale at 8‐, 16‐ and 24‐ weeks; 2. Quality of life will be measured using the EQ‐5D‐5L at 8‐, 16‐ and 24‐ weeks; 3. Interpersonal support will be measured using the Interpersonal Support Evaluation List – Short Scale at baseline, 8‐, 16‐ and 24‐ weeks; 4. Loneliness will be measured using the UCLA Loneliness Scale at baseline, 8‐, 16‐ and 24‐ weeks; 5. Resource Use will be measured using the Adapted Client Service Receipt Inventory at baseline, 8‐, 16‐ and 24‐ weeks; 6. Carer Impact will be measured using the Social‐care related quality of life (ASCOT‐CARER) and Warwick‐Edinburgh Mental Wellbeing Scale (WEMWBS) at baseline, 8‐, 16‐ and 24‐ weeks; INCLUSION CRITERIA: 1. Age between 16 ‐ 25 years. 2. A clinical diagnosis of Autism Spectrum Disorder (ASD)