Ertanir, BeyhanKassis, WassilisGarrote, Ariana2021-12-032021-12-032021-12-021661-78271660-4601https://doi.org/10.3390/ijerph182312734http://dx.doi.org/10.26041/fhnw-3989https://irf.fhnw.ch/handle/11654/32865.1This study aimed to explore changes in mental health outcomes (depression, anxiety, home, and school stress) from before the first COVID-19 wave (autumn 2019) to the later stages of the same wave (autumn 2020) in a sample of N = 377 Swiss adolescents (Mage = 12.67; 47% female. The results showed that the expected impact of the pandemic on mental health was not noticeable in the later stages of the first COVID-19 wave. Only two effects were demonstrated in terms of intra-individual changes, namely, an effect of gender on depression and anxiety symptoms and an effect of reported COVID-19 burden on school stress symptoms. Moreover, few associations were found for selected predictors and students’ mean level scores, averaged across both time points.en-USCC0 1.0 UniversalCOVID-19mental healthdepressionanxietystressadolescence370 - Erziehung, Schul- und Bildungswesen610 - Medizin und Gesundheit150 - Psychologie01A - Beitrag in wissenschaftlicher Zeitschrift12734