Autism affects approximately 605,000 individuals in the UK. People with autism are vulnerable in several contexts throughout the lifespan (e.g. community, service settings, criminal justice system). There is little empirical research that explicitly focuses on vulnerability in people with autism. This project will identify and quantify areas of vulnerability so that recommendations for tailored support can be made. The proposed research aims to get a broad but detailed representation of vulnerability issues faced by people with autism, with and without intellectual disability (ID). A key aim is to identify the risk factors for their mental health. We will use a community-based participatory research (CBPR) model to develop and conduct a survey. We will hold a series of focus groups with members of the autism community and professionals working in a variety of settings. We will conduct individual interviews that will inform the design of the online survey. We will address three overarching questions: 1. What are the characteristics of people with autism (with and without ID) that increase the vulnerability risk? This takes a syndrome-centred approach and will inform us about the causes of risk for vulnerability within the person. 2. What are the situational and social factors that serve to increase or reduce vulnerability in this population? This takes a context-centred approach and will inform us about the structure of agencies and institutions, and working practices that help or exacerbate vulnerability in autism. 3. What are the key areas in the life of a person with autism where risk of vulnerability is greatest? This takes a developmental transitionscentred approach and will inform us about when services need to be particularly ready to provide support and intervention. We will recruit research volunteers with autism and their family members, registered at two volunteer databases (ASD-UK, and the Cambridge Autism Research Database, or CARD) as well as adults who have been diagnosed at the CLASS clinic in Cambridge. The survey will elicit both quantitative and qualitative responses. The primary output will be to translate the research findings into national policy recommendations