ABSTRACT
Objectives Control measures enacted to control the spread of COVID-19 appear to have impacted adolescent movement behaviours. It remains unclear how these changes relate to sociodemographic characteristics and indicators of mental health. Understanding these relationships can contribute to informing health promotion efforts. The purpose of this study is to examine sociodemographic and mental health characteristics associated with changes in movement behaviours (physical activity, screen time, sleep duration) due to the COVID-19 pandemic among adolescents. Methods This cross-sectional study used May–June 2020 survey data and included 7349 students from Quebec, Ontario, and British Columbia (Canada). ANOVA, χ2 tests, and estimation of effect sizes using Cohen’s d and h tests were performed between self-reported perceived changes (increase;decrease;no change) to physical activity, TV watching, social media use, and sleep duration as a result of the COVID-19 pandemic and gender, age, race/ethnicity, income, depression and anxiety symptoms, flourishing-languishing, and self-rated mental health. Results Over half of students reported increases in TV viewing and social media use and approximately 40% reported decrease in physical activity and increase in sleep duration due to the COVID-19 pandemic. More females (68.9%) than males (54.3%) reported increase in social media use (Cohen’s h ≥ 0.2–0.5). No change from pre-COVID-19 social media use and sleep duration were associated with fewer depression and anxiety symptoms and better self-rated mental health compared to reports of an increase or decrease. These effect sizes ranged from small-to-moderate to moderate-to-large (Cohen’s d/h ≥ 0.2–0.8). Decreased physical activity and sleep duration were associated with better psychological functioning with effects sizes of small-to-moderate. Compared to an increase or no change, decreased sleep had the largest effect size of less frequent depression symptoms (Cohen’s d ≥ 0.5–0.8). Conclusion Maintaining pre-COVID-19 screen time and sleep duration during early stages of the COVID-19 lockdown was generally beneficial to mental health, with sleep being particularly important in regards to symptoms of depression. Psychological functioning was more related to physical activity and sleep than screen time during the pandemic.