COVID-19 impact on adolescent mental health: A reassessment accounting for development

Background: We examine whether age-related change over 11-14 years accounts for the increase in depression and behavioural problems associated with the pandemic.Methods: Parents and adolescents in a UK-based birth cohort (Wirral Child Health and Development Study; WCHADS; N=737) reported on adolescent depression and behavioural problems pre-pandemic (February 2020), mid-pandemic (August 2020) and late-pandemic (August 2021). Analysis used repeated measures models for over-dispersed Poisson counts with a child-specific intercept with age as a time -varying covariate. Results: The pre-pandemic subsample (56% response) did not differ on socio-demographic or risk characteristics from the full sample, response was 87% at mid and 82% at late- pandemic. Maturational curves for girls, but not for boys, showed a significant increase in self-reported depression symptoms over ages 11-14 years. Behavioural problems decreased for both. After adjusting for age-related change, girls’ depression increased by only 13% (CI -1%, 27%) at mid-pandemic and returned to near pre-pandemic level at late-pandemic (mid versus late -12% CI -29%,6%), whereas boys’ depression increased by 31% (CI 10%,51%) and remained elevated (mid versus late 1%, CI -22%,+25%). Age-adjusted behavioural problems increased for both (girls 40%, CI 21%,60% and boys 41%, CI 20%,61%) and worsened from mid to late-pandemic (girls 33%, CI 1%, 65%; boys 18%, CI -12%,+48%). Conclusions: Initial reports of a pandemic related increase in depression in young adolescent girls could be explained by a natural maturational rise. In contrast, maturational decreases in boys’ depression and both boys’ and girls’ behavioural problems may mask an effect of the pandemic.