Abstract
The potential impact on mental health of home schooling and social isolation due to COVID-19 lockdowns has led to widespread concern, particularly for adolescents. However, studies including pre-pandemic data from longitudinal cohorts with an assessment of the longer-term impact of the Covid-19 pandemic beyond the first months of 2020 are scarce. This longitudinal study of 1534 adolescents attending a secondary school in Hunan province investigated self-reported symptoms of anxiety and depression using two validated scales (Screen for Child Anxiety Related Disorders, Child Mood and Feelings Questionnaire) at six time points before, during, and after the 2020 national lockdown restrictions in China. Perceived COVID-related stress was assessed by an author-developed scale at two timepoints during the lockdown. We investigated trends in symptoms over time with a fixed effects model and multiple imputations of missing data. Counter to our expectations, depressive and anxiety symptoms were reduced during the 2020 lockdown relative to pre-lockdown (depression: b = - 3.37, SE = 0.345, Cohen's d = - 0.25, p < 0.0001; anxiety: b = - 4.55, SE = 0.382, Cohen's d = - 0.30, p < 0.0001). Symptoms remained significantly reduced even after lockdown restrictions eased. Higher symptom levels during lockdown were associated with greater self-reported COVID-related stress (depression: b = 0.11, SE = 0.026, p < 0.0001; anxiety: b = 0.11, SE = 0.036, p < 0.0001). Although COVID-related stresses correlated with higher levels of anxiety and depression, the lockdown period was associated with improved symptom levels in the adolescents taking part in our study. School closures may have improved the mental health of adolescents in China. We speculate this beneficial effect of lockdown can be explained by the adverse effects of attending school itself such as exposure to bullying and achievement pressures.