Association of Intellectual and Developmental Disabilities with Mental Health and Neurologic Disorders Among U.S. Adult Emergency Department Patients

Background and Purpose: Adults with intellectual and developmental disabilities (IDDs) display high prevalence of dual mental health and neurologic comorbidities and poor access to neuropsychiatric care. Little is known about the role of the emergency department (ED) in meeting these needs because there are few national data sources regarding U.S. adults with IDDs. This analysis helps to fill this research gap by examining the prevalence of mental health and neurologic diagnoses among adults with versus without IDDs visiting the ED.

Methods: We conducted a cross-sectional study of ED visits at U.S. hospitals in 2019 using the Nationwide ED Sample (NEDS). Validated algorithms were used to identify and compare mental health and neurologic diagnoses among ED patients older than age 18 with versus without diagnosed IDDs (intellectual disability, autism spectrum disorder, cerebral palsy) at the time of visit. We examined diagnosed mental health or neurologic condition, including depression, anxiety, schizophrenia, suicidality, seizure, dementia, and sleep disorder in different patient populations.

Results: We identified 558,408 and 112,593,527 (weighted) ED visits for adults with and without IDDs, respectively. Patients with IDDs were more likely to be younger than age 65 (86.7% vs 73.9%), male (58.9% vs 43.2%), White (69.7% vs 58.8%), and to pay with Medicaid (62.9% vs 29.5%) or Medicare (52.7% vs 30.2%) (p<.001). Patients with IDDs had a 5.72 (95% CI, 5.05-6.40) percentage point greater likelihood of a principal visit diagnosis of mental health disorder, with accompanying higher probabilities of suicidality (0.76, 0.62-0.90), neurologic disorder (3.82, 3.61-4.03), and seizure disorder (3.74, 3.53-3.95) as the primary reason for their visits. Patients with intellectual disabilities displayed 193% greater likelihood of comorbid dementia (p<.001). Early dementia was particularly prevalent among patients living with Down Syndrome. Among those ages 45-49, patients living with Down Syndrome displayed nearly one hundred times the dementia diagnosis rate observed among other patients in the same age range, and 2.67 times the rates observed among general-population patients over age 70.

Conclusions and implications: Public discourse regarding persons with IDD frequently focuses on the needs of children, adolescents, and young adults, with the richest array of services available to children and youth through public school systems. The needs of adults with IDD, including older adults, receive less attention, at-times leading policymakers and the public to overlook the distinctive challenges associated with IDD in adult medical care. We find that adults living with IDDs are substantially more likely to experience mental health and neurologic disorders as indicated causes of their ED encounters. Challenges related to early dementia are particularly great among persons with Down syndrome. Such patterns underscore the need to prepare emergency departments, families, and social service providers in addressing these challenges, and the need for service systems for persons with IDDs that provide appropriate services and care at every life stage.