A systematic review and meta-analysis of longitudinal cohort studies comparing mental health before versus during the COVID-19 pandemic

Robinson, E.; Sutin, A. R.; Daly, M.; Jones, A.

Background: Increases in mental health problems have been observed in some studies during the COVID-19 pandemic. It is unclear whether changes have been large and experienced by most population sub-groups, persisted over time or been symptom specific. Methods: We systematically reviewed and meta-analysed longitudinal cohort studies that examined changes in mental health among the same group of participants before and during the pandemic (PROSPERO: CRD42021231256). Searches for published and unpublished studies were conducted in January 2021. Changes in mental health (standardised mean change; SMC) were examined using meta-analyses. Findings: Sixty-five studies were included. There was an overall increase in mental health symptoms that was most pronounced during March-April 2020 (SMC = .102 [95% CI: .026 to .192], p = 0.03) before significantly declining over time (May-July SMC = .067 [95% CI: -.022 to .157], p = .141). Compared to measures of anxiety (SMC = 0.13, p = 0.02) and general mental health (SMC = -.03, p = 0.65), increases in depression and mood disorder symptoms tended to be larger (SMC = 0.22, p < .001) and reductions over time appeared less pronounced. Increased mental health symptoms were observed across most population subgroups examined but there was no evidence of any change in symptoms among samples with a pre-existing mental health condition. Interpretation: There was a small increase in mental health symptoms soon after the outbreak of the COVID-19 pandemic that decreased and was comparable to pre-pandemic levels by mid-2020 among most population sub-groups and symptom types. Funding: N/A