Anxiety and Depressive Symptoms Before and During the COVID‐19 Pandemic: A Longitudinal Network Analysis

Background: Despite the societal impact of the COVID-19 pandemic, research assessing changes in symptoms of anxiety and depression following the sanitary crisis has reported heterogeneous evidence, especially among individuals with pre-existing mental health conditions. Most earlier studies used summary scores of depression or anxiety assessment surveys, which does not provide insights into changes in individual symptoms and symptom structure during the pandemic. Objective: This study used a network analysis to investigate the symptom structure of anxiety and depressive symptoms and temporal changes in symptoms across three timepoints before and during the COVID-19 pandemic in a sample primarily of persons with anxiety and depressive disorders. Methods: Data are retrieved from 675 participants of the Netherlands Study of Depression and Anxiety (NESDA) and Netherlands Study of Depression in Older Persons (NESDO) cohorts who completed all three timepoints. Anxiety and depressive symptoms were assessed using the Beck anxiety inventory (BAI) and the Quick Inventory of Depressive Symptomatology-Self-Rated (QIDS-SR). Symptom networks were estimated for three timepoints: pre-COVID, first COVID-peak (April 2020), second COVID-peak (January/February 2021), and compared. Symptom importance was quantified using centrality indices (strength, betweenness, and closeness), and temporal stability was assessed using the network comparison test (NCT). Results: The symptom networks were largely consistent between the two COVID-19 peak timepoints but differed significantly from the pre-COVID network in terms of global strength. Fear-related anxiety symptoms, sleep-related symptoms, and thoughts of death or suicide demonstrated greater strength centrality at the pre-COVID timepoint compared to both COVID-19 peak timepoints. Conclusion: Our findings illustrate that a stressful situation, such as the COVID-19 pandemic, can result in changes in the complex associations of anxiety and depressive symptoms. Unexpectedly, anxiety symptom networks shifted from being driven by somatic fear responses before the pandemic, toward greater prominence of cognitive appraisal symptoms during the pandemic. Network insights could help focus intervention planning by targeting the key symptoms of anxiety and depression.