Periodicity and severity of changes in depression and anxiety during the COVID-19 pandemic: Ten-wave longitudinal findings from an observational cohort study of community adults

Aims: Few multi-wave longitudinal studies have examined mental health changes across the coronavirus 2019 (COVID-19) pandemic. The current study examined: (a) overall changes in depression and anxiety over 10-waves of data collection; (b) subgroup moderators of changes; (c) clinical severity of the changes via minimally important differences (MIDs); and (d) correlates of clinically important changes. Methods: Using a longitudinal observational cohort design, 1412 non-clinical adults (Mage=36; 60% female) were assessed for depression and anxiety via the PHQ-9 and GAD-7 from October 2018 to April 2022 (3 pre-pandemic, 7 intra-pandemic waves; M retention = 92%).Results: Depression and anxiety exhibited significant intra-pandemic changes, reflecting initial increases, fol-lowed by decreases. Pre-pandemic severity moderated changes, with low severity participants exhibiting in-creases and high severity participants exhibiting non-significant change or decreases. For depression and anxiety, respectively, 10% and 11% exhibited MID increases, while 4% and 6% exhibited MID decreases. Divergent patterns were present by severity subgroup, with the lowest severity exhibiting higher rates of MID increases and the highest severity subgroup exhibiting higher rates of MID decreases.Conclusions: These findings illuminate the periodicity of depression and anxiety during the COVID-19 pandemic and reveal an unexpected inverse relationship between increases and decreases based on pre-pandemic severity.

Automated summary

This study examined the mental health changes during the COVID-19 pandemic through 10 waves of data collection. Depression and anxiety showed significant changes, initially increasing and then decreasing over time. The severity of depression and anxiety before the pandemic moderated these changes, with lower severity participants experiencing increases and higher severity participants showing no significant change or decreases. Approximately 10% to 11% exhibited minimal important differences (MID) increases in depression and anxiety, while approximately 4% to 6% exhibited MID decreases.