Background
Mental-health-disorders in children/young adults increased post-pandemic; however, the absence of linkage to COVID-19 registries made direct attribution of psychological sequelae to acute infection challenging.
Methods
Healthcare-claims databases in Singapore were utilised to evaluate rates of new-incident mental-health-disorders in children/young adults aged 6–25 years from January 1st, 2012 to 29th February, 2024. Influence on monthly observed new-incident mental-health-disorders across various pandemic phases was modelled using negative binomial regression, accounting for seasonality and overall increasing trend (year). Separate linkage with the national COVID-19 database allowed construction of contemporaneous SARS-CoV-2-infected/test-negative cohorts. Cox regression, with overlap weights applied, was utilised to estimate risks of new-incident medically-diagnosed mental-health-disorders 31–300 days post-infection versus test-negatives.
Results
Overall, there was no significant increase in risk for any new-incident medically-diagnosed mental-health-disorders (adjusted-hazards-ratio, aHR = 1.01 [95% CI = 0.90–1.12]) amongst SARS-CoV-2-infected children/young adults (N = 456,034) versus test-negatives (N = 482,588); with the sole exception that of stress/anxiety disorders (aHR = 1.20 [95% CI = 1.02–1.40]). Only infections during the pandemic-containment-phase were associated with significantly increased risk of stress/anxiety, but not during the pandemic-resiliency-phase when restrictions were lifted (pandemic-containment: aHR = 1.25 [95% CI = 1.02–1.54]; pandemic-resiliency: aHR = 1.15 [95% CI = 0.89–1.48]). Risk of stress/anxiety was elevated amongst COVID-19 cases with a concurrently-infected adult household contact. A 10% increase in new-incident mental-health-disorders was observed amongst Singaporean children/young adults during the pandemic-containment-phase, but this subsequently normalised in the pandemic-resiliency-phase.
Conclusions
Increase in medically-diagnosed mental-health-disorders amongst Singaporean children/young adults at the height of pandemic restrictions did not persist into endemicity. Increased incidence of medically-diagnosed stress/anxiety post-COVID-19 in children/young adults at the pandemic height may be mediated by initial infection severity and concurrent household infection.