Mental health hospitalization and readmission in autistic adults in a national U.S. sample.

Objective: The objectives of this study were to, 1) estimate U.S. national rates of mental health hospitalization (MHH) and all-cause readmission, and 2) explore characteristics associated with readmissions for autistic and non-autistic adults. Methods: This study used the National Readmission Database (NRD) 2019 to examine 30-day all-cause readmissions following MHH in adults with autism, intellectual disability, ADHD, and mental health conditions. Analysis estimated rates of MHH by group, rates and odds of readmission, and factors associated with readmission. Results: More than one-third (36 %) of all admissions for autistic adults in 2019 were MHH, with schizophrenia the most common reason. Of all MHH index events in autistic adults, 17 % had a 30-day all-cause readmission. Readmissions were more common in autistic adults with ID (25 %) than in autistic adults without ID (15 %). Readmission was also slightly more common in female autistic adults (20 %) than male autistic adults (16 %), and autistic females had greater odds of readmission (OR 1.30, 95 % CI 1.09, 1.55) than autistic males, which was not true in non-autistic adults. Initial admission for schizophrenia was associated with increased odds of readmission for all groups (OR 1.37, 95 % CI 1.32, 1.42). Conclusions: The complexity of mental health conditions and their care in autistic adults underscores the urgent need for accessible and tailored mental health care services. Addressing these challenges will require collaborative efforts across healthcare sectors to create comprehensive, inclusive, and person-centered approaches to mental health care delivery for autistic adults across often disjointed service sectors.