Publication date: Sep 22, 2025
To date, little is known about the evidence of a potential risk of psychiatric adverse events following COVID-19 vaccination in large populations with adequate study design. To investigate whether COVID-19 vaccination is associated with increased risk of psychiatric adverse events. We used South Korea’s linkage database to obtain registry data and claims data from 2019 to 2021, and conducted a population-based self-controlled case series study including 11 751 806 individuals. Primary outcomes included anxiety/nervousness, mood disorders, perceptual disturbances/psychoses, aggression/behavioural disturbances, cognitive impairments and sleep disorders within 21 days of COVID-19 vaccination. Secondary outcomes were the stratified primary outcomes according to each individual’s psychiatric history. Conditional Poisson regression was used to estimate incidence rate ratios (IRR) and 95% confidence intervals. COVID-19 vaccination did not increase the rate of anxiety and nervousness (adjusted IRR 0. 95, 95% CI 0. 95-0. 96), mood disorders (adjusted IRR 0. 75, 95% CI 0. 75-0. 76), perceptual disturbances and psychoses (adjusted IRR 0. 72, 95% CI 0. 70-0. 74), aggression and behavioural disturbances (adjusted IRR 0. 93, 95% CI 0. 89-0. 97), cognitive impairment (adjusted IRR 0. 68, 95% CI 0. 67-0. 69) or sleep disorders (adjusted IRR 0. 90, 95% CI 0. 89-0. 91). Secondary outcomes were consistent with the primary outcome, although the adjusted IRRs for anxiety and nervousness (adjusted IRR 1. 17, 95% CI 1. 15-1. 18) and sleep disorders (adjusted IRR 1. 07, 95% CI 1. 06-1. 09) were statistically significant in individuals with no history of psychiatric disorders. Sensitivity analyses showed consistent results with our main findings. Our findings provide short-term safety profiles for COVID-19 vaccines regarding psychiatric adverse events. Continuous monitoring of anxiety/nervousness or sleep disorders after COVID-19 vaccination is required regardless of history of psychiatric comorbidities.
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| Concepts | Keywords |
|---|---|
| Korea | COVID-19 vaccine |
| Nervousness | psychiatric adverse events |
| Vaccination | self-controlled case series |