Three years into the pandemic: results of the longitudinal German COPSY study on youth mental health and health-related quality of life.

Purpose: For the past three years, the German longitudinal COPSY () study has monitored changes in health-related quality of life (HRQoL) and the mental health of children and adolescents during the COVID-19 pandemic.

Methods: A nationwide, population-based survey was conducted in May-June 2020 (W1), December 2020-January 2021 (W2), September-October 2021 (W3), February 2022 (W4), and September-October 2022 (W5). In total,  = 2,471 children and adolescents aged 7-17 years ( = 1,673 aged 11-17 years with self-reports) were assessed using internationally established and validated measures of HRQoL (KIDSCREEN-10), mental health problems (SDQ), anxiety (SCARED), depressive symptoms (CES-DC, PHQ-2), psychosomatic complaints (HBSC-SCL), and fear about the future (DFS-K).