Trends in Mental Health Diagnoses Among Children and Adolescents Before and During the COVID-19 Pandemic in a Large German State.

Background/Objectives: During the COVID-19 pandemic, school closures and reduced peer interactions impaired the quality of life and mental health of young people. The aim of this study was to examine trends in mental health diagnoses among children and adolescents during the pandemic as compared to pre-pandemic periods in a large German state. Methods: We used secondary data for the period 2018-2022 from youths <18 years insured with AOK Lower Saxony (about 500,000 children and adolescents per year). Data included outpatient and hospital diagnoses, and socio-demographic information (including area deprivation). For depressive disorders, anxiety and eating disorders, as well as attention-deficit/hyperactivity disorder (ADHD), we calculated yearly incidence and prevalence, stratified by sex and age. Results: In 2021, the incidence was highest for anxiety disorders (34.7 per 1000 persons), followed by ADHD (18.0/1000), depressive disorders (13.7/1000), and eating disorders (2.7/1000). Compared to 2019, incidences increased for all four disorders in 2021, with changes being most pronounced in females aged 15-17 years (anxiety disorders: +23%, depressive disorders: +25%, ADHD: +54%, eating disorders: +90%), while trends were less clear for prevalences. In 2022, incidences and prevalences generally decreased but did not return to pre-pandemic values in adolescent girls. No consistent gradient across levels of area deprivation was observed. Conclusions: During the pandemic, we observed an increase in several mental health diagnoses as reflected by increased healthcare utilization among children and adolescents, particularly in adolescent girls. In this group the prevalence of mental health diagnoses remained high also in 2022. This underscores the necessity of providing targeted mental health support and monitoring long-term trends.