Internalizing Problems Before and During the COVID-19 Pandemic in Dutch Children and Adolescents with and without Pre-Existing Mental Health Problems

The aim of the study was to assess internalizing problems before and during the pandemic with data from Dutch consortium Child and adolescent mental health and wellbeing in times of the COVID-19 pandemic, consisting of two Dutch general population samples (GS) and two clinical samples (CS) referred to youth/psychiatric care. In each sample, measures of internalizing problems were obtained from ongoing data collections pre-pandemic (NGS= 35,357; NCS= 4,487) and twice during the pandemic, in Apr.-May 2020 (NGS= 3,938; clinical: NCS= 1,008) and in Nov.-Dec. 2020 (NGS= 1,489; NCS= 1,536), in children and adolescents (8-18 years) with parent- (Brief Problem Monitor) and/or child reports (Patient-Reported Outcomes Measurement Information System). Results show significantly greater proportions of worrisome internalizing problems (based on validated cut-offs) and significantly higher internalizing problems mean levels from pre-pandemic to pandemic measurements in the general population. These levels stabilized or decreased over the course of the pandemic. In the clinical sample, we found an increase in child-reported internalizing problems measures over the course of the pandemic, but parents reported no differences in internalizing problems measures over the course of the pandemic, nor from pre-pandemic to during the pandemic. Overall, the findings indicate that children and adolescents of both the general and clinical population were affected negatively by the pandemic in terms of their internalizing problems. Attention is therefore warranted to investigate what long-term effects this may cause and to monitor if internalizing problems return back to pre-pandemic levels or if they remain elevated post-pandemic.