We investigated the impact of COVID-19 pandemic on mental health outcomes, using a nationwide community health survey in South Korea. Among the total population, we found that the prevalence of moderate stress, extreme stress, and depression increased during the pandemic period (2020) after adjusting for the temporal trend of mental health, and increasing patterns were more pronounced in high population-density districts, and individuals who were aged 19–59 years, those with high education levels, and those with high household income than in mid and low population-density districts and in the general population. Also, the higher increases in moderate and extreme stress were associated with lower % that have mutual trust among neighbors; while, higher number of sports facilities and lower % with reduced physical activity due to the pandemic were associated with less increased stress during the pandemic. Furthermore, districts with higher local tax per person showed a higher increase in depression.
Our findings were generally consistent with those of previous studies4,5,12−15. Studies conducted in the United States reported that the prevalence of moderate and severe depression increased by nearly threefold during the pandemic, and increases in psychological problems were higher in younger adults than older adults by more than 10%12,14. A study conducted in the United Kingdom showed an increase in mental health prevalence by more than 5.5% among individuals with high education levels and high household income compared with individuals low education levels and low household income, respectively4,5. Another study conducted in South Korea also reported that the prevalence of depression increased by 49.8% during the pandemic, and the scores of moderate- to high-intensity exercise and social relationships decreased by 30% and 10% compared with those before the COVID-19 pandemic, respectively24. Other Chinese studies reported that the prevalence of mental illness in urban areas was 15.3%, which was significantly higher than 12.5% in rural areas during the pandemic25.
There are several plausible mechanisms that can explain the degenerated mental health during the pandemic. First, strong social distancing measures could affect the increase in mental health problems. Second, exposure to stressful news could indirectly affect the increase in psychological problems4. Third, social isolation, due to the fear of infection and restriction of social contact, could directly affect the increase in stress levels26. Fourth, a decrease in physical activities during the pandemic could also have a negative effect on mental health27. Finally, early compliance with social distancing policies could affect the increase in the prevalence of depression.
The increasing pattern in the prevalence of mental health outcomes during the pandemic differed by sub-district divided by population density, and the increase was more evident in high population-density districts than in other districts. We postulated that the more pronounced increase in prevalence of mental health outcomes in high population-density districts could be related to stricter restrictions applied to the same area. During the pandemic, the number of confirmed COVID-19 cases was the highest in high-population density districts (see Table 2); thus, restrictions in social gatherings were stronger in metropolitan/urban areas than in small urban and rural areas in South Korea28. Thus, in urban areas, the number of people allowed to enter restaurants was regulated, and public transportation operations were also decreased. Although these restrictions might be effective in reducing the spread of COVID-1929, they could cause the inconvenience and impose additional stress to urban residents. Our findings provide epidemiological evidence for mental health policies that are more prioritized for urban populations.
Our study also showed that younger people and individuals with a high SES showed more evident increase in mental health prevalence during the pandemic. We conjecture that the disparities in accessibility to information could be majorly associated with these results. Previous studies reported that individuals confront anxiety-provoking information through the social media, and more frequent exposures to such information can cause higher vulnerability to mental health degeneration when the future is unpredictable30. In addition, young and middle-aged, highly educated, and higher income populations may be more likely exposed to negative information from the Internet and social media than the general population31,32. Therefore, this might be related to a higher increase in the prevalence of mental health outcomes during the pandemic.
In this study, a lower % that have mutual trust among neighbors was associated with higher increases in the prevalence of stress during the pandemic. We postulated that social isolation might be associated with these results. Low mutual trust between neighbors could lead to weakened social ties and isolation from community, which are important risk factors for mental health problems26. Further, higher % with reduced physical activity due to the pandemic and lower number of sports facilities were associated with higher increases in the prevalence of stress during the pandemic. We speculate that low accessibility to sports facilities might have affected these findings. It is well known that physical activities are associated with lower levels of mental health problems27, and sports/recreational facilities provides better environments for recreational activities and exercise, which can alleviate stress33,34.
Further, local tax per person was positively associated with increase in depression. We postulated that different levels of response to social distancing policies by district-level SES could be linked to a change in depression levels during and before the pandemic. Previous studies reported that mobility in cities with higher SES decreased faster than cities with lower SES following lockdown35,36. As the social distancing policies went on, residents in high SES districts seem to have more trouble engaging in recreational or outdoor activities36, which help in reducing concerns and worries37. In contrast, there was no association between district-level SES and increase in stress, and this result could be affected by stress resilience38. Because community resources that related to community resilience are generally more distributed in districts with higher SES than lower SES, stress levels in districts with high SES might have reduced compared to levels onset of pandemic. Since resilience could mediate the relationship between stress and depression39, it is plausible that depression in districts with high SES might also recover as time goes by; however, it should be proved on future studies.
This study has some limitations. First, there may be latent problems with regard to misclassification or recall bias due to the limitations of self-reported data. However, the KCHS was run by trained interviewers, and the quality of the KCHS was well managed systematically21; therefore, bias in our results would be small. Second, because we used a cross-sectional survey that did not provide individual follow-up data, causal relationships could not be established in this study. Third, because of the high correlation among the regional variables as shown in the PCA result, we could not consider them simultaneously in the model. Further study should consider appropriate methods to address this issue.