Pre-pandemic sleep behavior and adolescents' stress during Covid-19: a prospective longitudinal study.

Objective: To prospectively document changes in adolescents' sleep before versus during the COVID-19 pandemic, and to examine their impact on adolescents' perceived stress.

Methods: Sixty-two typically developing adolescents participated in the study before (Time 1: January 15 to March 13, 2020) and during (Time 2: May 15 to June 30, 2020) the COVID-19 pandemic in Canada. At Time 1, each participant's sleep pattern was assessed in the home environment using actigraphy and sleep logs for seven consecutive nights.