Understanding the effect(s) of the COVID-19 pandemic is key for planning for future pandemics.

This study examines change in self-reported mental health difficulties during three months of the pandemic among adolescent (10- to 15-year-olds) participants from the UK Household Longitudinal Study (waves 7, 9 and 11 of the main survey and waves 4, 5 and 8 of the COVID-19 surveys).

We focused on mental health difficulties using the Strengths and Difficulties Questionnaire (SDQ), using repeated cross-sectional and longitudinal analyses to examine data among 6471 adolescents who responded to at least one survey since 2015, and 2,300 who responded to at least one COVID-19 survey during July 2020, November 2020 or March 2021.

Repeated cross-sectional data showed similar mean total SDQ across surveys before and during the pandemic (range during pandemic 11.4 to 11.9; range pre-pandemic 11.1 to 11.8). Longitudinal analyses provided no evidence of mental health change compared with pre-pandemic trends (estimated change mean SDQ (β) = 0.05, 95% CI −0.42 to 0.51; p = 0.85), or differential sociodemographic effects, except greater effects in rural households (β = 0.67, 95% CI −0.08 to 1.41) than urban environments (β = −0.18, 95% CI −0.69 to 0.33). Though subscales generally saw higher scores during the pandemic than before, these were consistent with pre-pandemic trends, excepting a slight improvement in conduct problems (β = −0.26, 95% CI 0.12 to 0.40).

The study offers evidence among a representative sample that mental health difficulties did not, on average, deteriorate for adolescents during three months of the pandemic.