Abbreviations: N: sample size; SD: standard deviation; t1: 1 semester after almost exclusively remote schooling (February 3^rd to February 28^th 2021); t2: at the begin of the second semester of reopened schools (14^th September 2021 to 14^thNovember 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).

Table 3. Statistics for the comparison between t1 and t2 (matched sample analyses).