PROJECT ABSTRACT The proposed study requests funding to conduct the most comprehensive examination to date of autistic adults (aged 40+) as they age, with the goal of gaining a comprehensive national picture of health and mental health outcomes and service needs. We will use analyses of national Medicaid and Medicare data complemented by surveys and interviews of middle aged and older autistic adults and their caregivers. The majority of research on autism spectrum disorder (ASD) has been focused on youth, but dramatic increases in the prevalence of ASD over the past three decades, the lifelong presentation of ASD, high costs of care in later segments of the lifespan, and the fact that little is known about the estimated 3.5 million autistic adults in the US who are over the age of 40, highlight the urgency of identifying the care needs of aging adults in order to improve health and mental health outcomes, costs of care, and quality of life for individuals and their families. This need for information and clinical guidance is underscored by emerging evidence of the early onset of neurological conditions such as Alzheimer’s Disease and related dementias and Parkinson’s Disease in autistic adults. As the largest healthcare insurers in the US, Medicaid and Medicare are critical sources of care for autistic adults as they age, and claims data provide a vital window for observing the prevalence and emergence of conditions, including specific neurological conditions associated with aging, and studying potentially adverse effects on health and mental health outcomes and service use. By comparing autistic adults to those without autism, we can gain further insight into comparative needs and resources. Medicaid and Medicare data are also optimal sources for studying inequities among economically disadvantaged individuals and diverse racial/ethnic groups who disproportionately experience poorer health and mental health care and subsequent suboptimal outcomes. We will link national Medicaid and Medicare data from 2014-2023, the latest years available, data about mortality, and data about communities for autistic individuals ages 40 through the end of life, and a comparison group of adults without autism. A Community Advisory Board of autistic adults will be engaged to inform a survey of a national sample of 700 autistic adults (or their caregivers), as well as interviews with a subset of survey participants, to yield contextual, real-world information about differences in health and mental health services access and utilization at individual, family, and community levels. Pairing findings from claims data with insights from the lived experiences of aging autistic adults will allow us to drive patient-centered improvements in service delivery to move toward meeting the needs of autistic adults as they age into a period of increased risk for health and mental health diagnoses. This research will generate findings that are poised to identify and inform modifi...