IMPORTANCE Understanding how children's utilization of acute mental health care changed during the COVID-19 pandemic is critical for directing resources. OBJECTIVE To examine youth acute mental health care use (emergency department [ED], boarding, and subsequent inpatient care) during the second year of the COVID-19 pandemic. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional analysis of national, deidentified commercial health insurance claims of youth mental health ED and hospital care took place between March 2019 and February 2022. Among 4.1 million commercial insurance enrollees aged 5 to 17 years, 17 614 and 16 815 youth had at least 1 mental health ED visit in the baseline year (March 2019-February 2020) and pandemic year 2 (March 2021-February 2022), respectively. EXPOSURE The COVID-19 pandemic. MAIN OUTCOMES AND MEASURES The relative change from baseline to pandemic year 2 was determined in (1) fraction of youth with 1 or more mental health ED visits; (2) percentage of mental health ED visits resulting in inpatient psychiatry admission; (3) mean length of inpatient psychiatric stay following ED visit; and (4) frequency of prolonged boarding (>= 2 midnights) in the ED or a medical unit before admission to an inpatient psychiatric unit. RESULTS Of 4.1 million enrollees, 51% were males and 41% were aged 13 to 17 years (vs 5-12 years) with 88 665 mental health ED visits. Comparing baseline to pandemic year 2, there was a 6.7% increase in youth with any mental health ED visits (95% CI, 4.7%-8.8%). Among adolescent females, there was a larger increase (22.1%; 95% CI, 19.2%-24.9%). The fraction of ED visits that resulted in a psychiatric admission increased by 8.4%(95% CI, 5.5%-11.2%). Mean length of inpatient psychiatric stay increased 3.8% (95% CI, 1.8%-5.7%). The fraction of episodes with prolonged boarding increased 76.4%(95% CI, 71.0%-81.0%). CONCLUSIONS AND RELEVANCE Into the second year of the pandemic, mental health ED visits increased notably among adolescent females, and there was an increase in prolonged boarding of youth awaiting inpatient psychiatric care. Interventions are needed to increase inpatient child psychiatry capacity and reduce strain on the acute mental health care system.
