Changes in child and adolescent mental health across the COVID-19 pandemic (2018-2023): Insights from general population and clinical samples in the Netherlands

Background The COVID-19 pandemic negatively affected child and adolescent mental health and at the end of the pandemic (April 2022) child mental health had not returned to pre-pandemic levels. We investigated whether this observed increase in mental health problems has continued, halted, or reversed after the end of the pandemic in children from the general population and in children in psychiatric care. Methods We collected parent-reported and child-reported data at two additional post-pandemic time points (November/December 2022 and March/April 2023) in children (8-18 years) from two general population samples (N=818-1056 per measurement) and one clinical sample receiving psychiatric care (N=320-370) and compared these with data from before the pandemic. We collected parent-reported data on internalizing and externalizing problems with the Brief Problem Monitor (BPM) and self-reported data on Anxiety, Depressive symptoms, Sleep-related impairments, Anger, Global health, and Peer relations with the Patient-Reported Outcomes Measurement Information System (PROMIS®). Results In the general population, parents reported no changes in externalizing problems but did report higher internalizing problems post-pandemic than pre-pandemic. Children also reported increased mental health problems post-pandemic, especially in anxiety and depression, to a lesser extent in sleep-related impairment and global health, and least in anger. In the clinical sample, parents reported higher internalizing, but not externalizing problems post-pandemic compared to the start of the pandemic. Children reported greatest increases in problems in anxiety, depression, and global health, to a lesser extent on sleep-related impairment, and least on anger. Conclusions Child mental health problems in the general population are substantially higher post-pandemic compared to pre-pandemic measurements. In children in psychiatric care mental health problems have increased during the pandemic and are substantially higher post-pandemic than at the start of the pandemic. Longitudinal and comparative studies are needed to assess what the most important drivers of these changes are. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was funded by ZonMw project number 50-56300-98-973. Data collection by KLIK (measurement 1 and 2) was supported by Stichting Steun Emma Kinderziekenhuis. PROMIS reference data collection was supported by the National Health Care Institute and the Netherlands Organization for Health Research and Development. Data collection in the NTR was supported by: NWO large investment (480-15-001/674; Netherlands Twin Registry Repository: researching the interplay between genome and environment). MB is supported by a European Research Council consolidator Grant (WELL-BEING 771057 PI Bartels). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: We received approval for data collection from the appropriate ethics committees, including the Medical Ethics Committee Amsterdam UMC, the Netherlands. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.