Mental health changes in different adolescent groups from before to throughout the COVID-19 pandemic

Background: The COVID-19 pandemic is assumed to have had a large impact on the mental health of adolescents. Finding out for which youth the mental health impact was largest is imperative for strengthening future crisis responses. In this study, we aimed to assess the impact of the pandemic on the mental health of different sociodemographic groups of general population adolescents in Flanders, Belgium. Methods: Adolescents were tested for the SIGMA study, at W1 (n=1913; mean age=13.8; 63.1% female; 2018/2019); W2 (n=272; mean age=16.5; 74.0% female; 2020); and W3 (n=227; mean age=18.0; 78.4% female; 2022/2023). Subclinical anxiety, depression, psychoticism, and general psychopathology were measured with the Brief Symptom Inventory-53. Multilevel linear regression models with imputed data sets were used to test cross-wave differences in each psychopathology outcome (controlling for age-related increases), effects of time since the beginning of the pandemic and stringency of pandemic-related measures, and effects of several sociodemographic predictors on levels and changes in psychopathology (from W1 to W2, and from W1 to W3). Results: Results indicated limited overall early increases in psychopathology (only for depression from W1 to W2), and some decreases in psychopathology levels from W1 to W3 (for anxiety and general psychopathology). Girls and those reporting same-gender attraction reported higher levels of nearly all symptoms. Conclusion: Although most youth in this sample were resilient during the COVID-19 pandemic, some groups consistently showed high psychopathology levels. Attention is still needed for groups that were at risk before the pandemic, notably, LGTBQIA+ youth.