National Trends in Emergency Department Visits by Adults With Mental Health Disorders.

Background: Although mental health disorders (MHDs) affect as many as 1 in 4 adults in the U.S., the national trends in emergency department (ED) use for adults who have MHD comorbidities are unknown.

Objective: To evaluate the role of mental health disorder co-morbidities for adults who use the ED and how this utilization differs by insurance type.

Methods: This is a retrospective analysis of the National Emergency Department Survey (NEDS) dataset of adults 18 to 64 years of age that was conducted from 2006 to 2011. We defined individuals with MHD comorbidities by applying the MHD Clinical Classification Software groupings to any of the 1 to 15 diagnostic fields available in the NEDS. We further evaluated ED visits made for a primary diagnosis of MHD by applying the same aforementioned codes to the primary diagnosis. We constructed ED visit rates using the U.S. Census Bureau's Current Population Survey. We used descriptive statistics and tested for differences in trends in visits and visit rates by payer using an ordinary least squares regression.

Results: The number of ED visits increased by 8.6% from 2006 to 2011. The number of ED visits made by adults primarily for MHDs and with MHD comorbidities increased by 20.5% and 53.3%, respectively (p < 0.0001); ED visits made adults without MHDs decreased by 1.1% (p = 0.72) for the same time period. When accounting for the population growth rate, ED visit rates made by adults with MHD comorbidities increased for all insurance types, but decreased for those without MHD comorbidities.

Conclusion: MHD comorbidities play a significant role in the increasing number of ED visits, regardless of insurance coverage. Additional studies are needed to understand the role of patients with MHDs and ED use.