Child Wellbeing during the COVID-19 Pandemic: A Multi-cohort Comparison and a Multi-informant Genetic Study.

The impact of the COVID-19 pandemic on the wellbeing of 26,555 Dutch children and adolescents (ages 8-18, 50% female, 89% with parents born in the Netherlands) was investigated using three cohorts: a general population twin sample (NTR), a general population sample (KLIK), and a clinical sample (DREAMS). Data were collected in seven waves between 2020 and 2023. Linear mixed models were employed to examine changes in wellbeing, twin models were used to estimate genetic and environmental contributions, and a psychometric model was employed to explore potential rater bias. A 6.5% drop in wellbeing was observed at the onset of the pandemic in the NTR sample, followed by partial recovery but not a return to pre-pandemic levels. Mean wellbeing scores were consistently lower in the clinical cohort (DREAMS), which also showed different effects of age, gender, and parental educational attainment compared to the two general population samples (NTR and KLIK). Increased disagreement between fathers' and mothers' ratings during lockdown was also identified. Genetic factors were found to account for 26-28% of the variance in wellbeing during the pandemic, and 34-35% before and after. Shared environmental factors were higher during the lockdown period (60-62%) compared to before and after the lockdown (45-49%), indicating the key role of family and home environment in that period. Multi-rater analyses suggested that part of this increase in shared environmental variance likely reflects rater bias rather than true environmental influences. These findings highlight that children in psychiatric care may face additional challenges compared to their peers and emphasize the importance of multi-rater assessments. Results suggest that both genetic predispositions and environmental disruptions should be considered when developing strategies to support child wellbeing during crises.