Variations in trajectories of emotional and behavioural symptoms in children and young people with pre‐existing mental health and neurodevelopmental conditions before and during the COVID‐19 pandemic: A nested data linkage clinical cohort study

Background Children and young people with pre‐existing mental health and neurodevelopmental conditions may have experienced heterogeneous mental health impacts during the COVID‐19 pandemic, but what facts may explain these variations are still unclear. We aimed to examine variations in the longitudinal trajectories of emotional and behavioural symptoms before and during the COVID‐19 pandemic in the United Kingdom (UK). Methods We used a novel nested clinical cohort study, linking the Maudsley Child and Young People Health and Experience Research (CYPHER) survey and electronic health records (EHRs) data of mental health service users (aged 5–17 years old) in South London and Maudsley NHS Foundation Trust, UK, on 1 June 2020 ( n = 388). Composite emotional and behavioural scores, including internalising and externalising symptoms, were assessed in June–September 2020 and February–March 2021 by the Maudsley CYPHER survey and the Strengths and Difficulties Questionnaire from EHRs was used to supplement data pre‐pandemic (2019–March 2020) and during the pandemic (2020 and 2021). Sociodemographic characteristics and diagnoses were extracted from EHRs. Relative symptom trajectories were modelled with predictors using linear mixed models. Results Relative emotional and behavioural symptoms were not significantly different from pre‐pandemic to 2021, but variations were found across predictors. Those who were female (vs. male; b = 0.19, 95% CI 0.02 to 0.36), lived in deprived neighbourhoods (vs. non‐deprived; b = 0.19, 95% CI 0.03 to 0.36), and had a diagnosis of autism (vs. emotional disorder; b = 0.33, 95% CI 0.13 to 0.53) had relatively higher emotional symptoms pre‐ and during pandemic. Those who were Black (vs. White; b = −0.48, 95% CI −0.82 to −0.14) or who did not state their ethnicity ( b = −0.47, 95% CI −0.82 to −0.12) had relatively higher decreases in emotional symptoms between pre‐pandemic and 2020. Those who had a diagnosis of intellectual disability (vs. without) had greater relative decrease in emotional symptoms between pre‐pandemic and 2020 ( b = −0.94, 95% CI −1.60 to −0.28) and 2021 ( b = −2.02, 95% CI −2.46 to −1.58). Those who were younger (vs. older; b = −0.03, 95% CI −0.06 to −0.01) and had a diagnosis of autism (vs. emotional disorder; b = 0.40, 95% CI 0.20 to 0.60) or attention‐deficit hyperactivity disorder (vs. emotional disorder; b = 0.43, 95% CI 0.19 to 0.66) had relatively higher behavioural symptoms pre‐ and during pandemic. Conclusion Emotional and behavioural symptoms were high and relatively stable across pre‐ and during pandemic timepoints. Relatively worse emotional and behavioural symptoms were observed in children and young people who were younger, female, lived in deprived neighbourhoods, and had a diagnosis of a neurodevelopmental condition. However, some effects might reflect distinctive features between groups rather than pandemic‐specific differences. Future research should examine longer‐term mental health impacts of the pandemic across clinical groups and potential mechanisms of change.