The impact of COVID-19 pandemic on sleep duration and mental health among middle school students: a 3-year cross-sectional survey

Meeting the SD standard is a protective factor for adolescent MH. The COVID-19 pandemic and its control measures have had a severe and long-term negative impact on both SD and MH in middle school students, with differences observed between genders and academic levels. The greater the severity of the pandemic and the stricter the control measures, the more significant the negative impact on SD and MH etc.