The long-term impact of the COVID-19 pandemic on the mental health of children and adolescents is yet unknown. We aimed to assess the impact of the COVID-19 pandemic on the rate of emergency department (ED) visits for mental health (MH) conditions and self-harm (SH) among children and adolescents (aged 6 to 17 years) in metropolitan France three years after the pandemic onset.

This is a national cohort study based on hospital medico-administrative data (PMSI – RPU database) collected in the pre-pandemic onset period (Jan. 2016 - Feb. 2020), initial pandemic period (March 2020 - May 2020), 1st post-pandemic year (June 2020 - May 2021), 2nd post-pandemic year (June 2021 - May 2022), and 3rd post-pandemic year (June 2022 - May 2023). Monthly rates of ED visits per 100,000 children and adolescents were modeled using a time-series analysis to assess changes in monthly rates and temporal trends and to calculate cumulative percent differences between estimated and expected ED visits rates in each post-pandemic period. The analysis was stratified by age and sex groups (children/adolescents; boys/girls), and by specific MH diagnosis.

A total of 432,725 ED visits were analyzed (13.8% children and 86.2% adolescents): 79.9% were related to a mental health condition and 20.1% related to intentional self-harm. Increasing trends were observed in ED visits for both MH conditions and SH before the pandemic onset. In the initial pandemic period, rates immediately and significantly dropped. Trends of ED visits for MH conditions increased during the first post-pandemic year only, whereas trends for SH visits increased in the first two post-pandemic years, and decreased thereafter. Overall, in the 1st post-pandemic year, the rate of ED visits for MH conditions decreased by 6.1% [-10.3%; -1.9%] and the rate of visits for SH increased by 10% [1%; 18.9%] compared to the expected rates. During the 2nd post-pandemic year, increases were observed in ED visits for both MH conditions (4.8% [4.4%; 5.2%]) and SH (46.4% [43.3%; 49.3%]). In the 3rd post-pandemic year, the rate of visits for MH decreased by 2.9% [-4.8%; -0.9%] and that for SH rose above the expected by 43.2% [40%; 46.5%]. While significant variations were observed between the different age and sex groups, adolescent girls were broadly the most affected group. Also, significant variations were observed regarding the MH diagnoses related to ED visits. The rate of ED visits for behavioral syndromes associated with physiological disturbances (mainly eating and sleep disorders) increased in all three post-pandemic years. The rate of ED visits for psychotic, mood, and pervasive developmental disorders increased in the second and third post-pandemic years only.

Three years after the onset of the COVID-19 pandemic, the rates of ED visits continue to rise above the expected for self-ham and for specific MH conditions in children and adolescents, especially in adolescent girls.