Psychoeducation for Adult Siblings of ASD People (Autism Spectrum Disorder).

The purpose of this study was to evaluate the effectiveness of a novel psychoeducational program for adult siblings of autistic individuals, aiming to improve autism-related knowledge, well-being, resilience and sibling relationship outcomes, while also highlighting the need for tailored supportive interventions for this population. The psychoeducational program will be implemented in adult siblings of people with ASD and its effectiveness will be assessed. We expect that after the intervention, participants in the intervention group will demonstrate improvements in the study outcomes compared with participants in the control group, and that some of these improvements will be maintained at the three-month follow-up. We further expect that the participants' level of caregiving involvement with their autistic sibling will be associated with the effectiveness of the intervention. No risk is identified.

Inclusion criteria were: (i) age 18 or older, (ii) having one sibling with a clinical diagnosis of ASD, (iii) no self-reported neurodevelopmental diagnosis, (iv) no prior participation in a psychoeducational program for autism and v) able to understand and communicate in Greek. Exclusion criteria were: (i) having more than one sibling diagnosed with ASD, and (ii) residing outside Greece. Participants were also required to have access to the internet and a device capable of participating in the online audiovisual sessions.