Canadian Journal of Behavioural Science / Revue canadienne des sciences du comportement
To date, most longitudinal studies of adolescents’ internalizing symptoms during the COVID-19 pandemic include few time points, limiting knowledge about the long-term course of adolescents’ mental health during the pandemic. Moreover, examining intraindividual variability in symptoms, which may have important implications for adolescents’ adjustment beyond mean or “typical” symptoms, requires multiple time points. We examined the course of internalizing symptoms in 271 Ontario adolescents (mean n = 193 across time points) during the first year of the pandemic (March 2020–April 2021) via mixed-effect location scale models, drawing upon established internalizing symptom risk factors as predictors of mean trends and intraindividual variability. Adolescents’ internalizing symptoms were relatively stable and generally low over the first year of the pandemic, with severity peaking in February and April 2021. Girls showed more symptoms on average and greater intraindividual variability in symptoms. Parents’ depressive symptoms predicted intraindividual variability in adolescents’ anxious and depressive symptoms. Adolescents’ symptoms were stable and generally below clinical cutoffs. However, female adolescents and those whose parents experienced more depressive symptoms were most vulnerable to the stress of the pandemic. Implications for intervention and prevention efforts are discussed.