Abbreviations: P: p-values (2-tailed); t1: 1 semester after almost
exclusively remote schooling (February 3rd to February
28th 2021); t2: at the begin of the second semester of
reopened schools (14th September 2021 to
14th November 2021);; ISI: Insomnia Severity Index,
GAD-7: Generalized Anxiety Disorder 7 scale; PHQ-9: Patient Health
Questionnaire 9 scale; WHO-5: Well-being questionnaire of the World
Health Organization (WHO); Cohen’s d was calculated as an effect
size measure for differences (small effect: 0.2 to 0.5, medium effect:
0.5 to 0.8, large effect: >0.8). CI: 95% confidence
interval.