IntroductionEmergency department (ED) utilization for psychiatric disease is increasing, and a lack of health insurance has been identified as a potential cause of preventable or avoidable ED use. Through the Affordable Care Act (ACA), more uninsured individuals gained health insurance; however, the effects of increased health insurance coverage on ED utilization for psychiatric disease have not been examined.MethodsWe performed a longitudinal, cross-sectional analysis of data from the Nationwide Emergency Department Sample, the largest all-payer ED database in the US, which contains data on over 25 million ED visits each year. We examined ED utilization for psychiatric disease as the primary reason for visit among adults aged 18–64. We compared the proportion of ED visits with a psychiatric diagnosis during post-ACA years (2011–2016) to pre-ACA (2009) using logistic regression adjusted for age, gender, payer, and hospital region.ResultsThe proportion of ED visits with psychiatric diagnosis increased from pre-ACA (4.9%) to post-ACA years (ranging from 5.0–5.5%). There was a significant difference in the proportion of ED visits with a psychiatric diagnosis when comparing each post-ACA year with pre-ACA, with adjusted odds ratios ranging from 1.01–1.09. Among ED visits with a psychiatric diagnosis, the most common age group was 26–49 years, and patients were more likely to be male than female and to have visited urban rather than rural hospitals. During post-ACA years (2014–2016), private and uninsured payers decreased, Medicaid payers increased, and Medicare payers increased in 2014 and decreased in 2015–2016 compared to pre-ACA.ConclusionWith the ACA more people gained health insurance, yet ED visits for psychiatric disease continued to increase. These results suggest that increasing access to health insurance alone is not sufficient to reduce ED utilization for patients with a psychiatric disease.