["Child and Adolescent Mental Health, EarlyView. ", "\n\nBackground\nMental‐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.\n\n\nMethods\nHealthcare‐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.\n\n\nResults\nOverall, 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.\n\n\nConclusions\nIncrease 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.\n\n"]