The adverse impact of consecutive COVID-19 waves on mental health

Background Although several studies documented the impact of COVID-19 on mental health, the long-term effects of COVID-19 on mental health remain unclear. Aims To examine longitudinal changes in mental health prior to and during the consecutive COVID-19 waves in a well-established probability sample. Method An online survey was completed by the participants of the COVID-19 add-on study at 4 timepoints (N1=1823, N2=788, N3=532, N4=383): pre-COVID period (2014/2015), 1st COVID-19 wave (April-May, 2020), 2nd COVID-19 wave (August-October, 2020) and 3rd COVID-19 wave (March-April, 2021). Data were collected via a set of validated instruments and analysed using latent growth models. Results During the pandemic, we observed a significant increase in stress levels (slope=1.127, P<0.001) and depressive symptoms (slope=1.177, P<0.001). The rate of increase in stress levels (cov=2.167, P=0.002), but not in depressive symptoms (cov=0.558, P=0.10), was associated with the pre-pandemic mental health status of the participants. Further analysis revealed two opposing clusters of factors that influenced mental health: loneliness and COVID-19 showed a negative effect on emotionality, while higher resilience acted protectively. A greater increase in stress was observed in women and younger participants. Conclusions The surge in stress levels and depressive symptoms persisted across all three consecutive COVID-19 waves. This surge is attributable to the effect of several risk factors including the status of mental health prior to the COVID-19 pandemic. Our findings have implications for strategies promoting resilience and addressing loneliness to mitigate the mental health impact of COVID-19 pandemic. ### Competing Interest Statement Maria Vassilaki has received research funding from Roche and Biogen in the past; she currently consults for Roche, receives research funding from NIH/NIA and EU/ St. Anne's University Hospital Brno (Czech Republic), and has equity ownership in Abbott Laboratories, Johnson and Johnson, Medtronic, Abbvie and Amgen. In addition, she is currently an Associate Editor for the Journal of Alzheimer's Disease and a Guest Editor for the Frontiers Research Topic collection "Multimorbidity in the Context of Neurodegenerative Disorders" (participating journals: Frontiers in Neuroscience-Neurodegeneration and Frontiers in Aging Neuroscience). Gorazd B. Stokin is currently an Associate Editor for the Frontiers in Aging Neuroscience journal. No other disclosures were reported. ### Funding Statement Supported by the European Regional Development Fund - Project ENOCH (grant no. CZ.02.1.01/0.0/0.0/16\_019/0000868) and MAGNET (grant no. CZ.02.1.01/0.0/0.0/15\_003/0000492). In part it was funded by Franke Global Neuroscience Education Center, Barrow Neurological Foundation. ### 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: The research protocol was approved by St. Anne's University Hospital ethics committee and the Internal Review Board. All participants were acquainted with the research and provided written informed consent. 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 and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The data used in this study are available on request immediately following the publication to anyone who submits the online request that will be approved by the St. Anne's University Hospital International Clinical Research Centre internal board. The researches have to provide their research intentions and goals, and specify, and justify requested variables. The data will be provided for a limited and well-defined time via cloud service or e-mail in csv format. After defined period the data should be returned, and all other copies should be destroyed.