The effect of COVID-19 on sleep quality and mental health: adolescents are more at risk than the elderly

After the appearance of a novel coronavirus (2019-nCoV) during 2019, the virus has spread with alarming speed and a pandemic quickly developed. The complex consequences of the pandemic phenomenon, i.e., the consequences of the pandemic per se and the countermeasures adopted to control infections and deaths, were associated with a negative impact on sleep quality [1] and, in general, mental health [2]. With a global prevalence of sleep disturbances of approximately 30–40%, as suggested by meta-analytical studies [3,4], a stable association with psychological distress has been repeatedly reported [5].