This study examined the depression and psychosocial experiences of the general public who had been quarantined because of the COVID-19 pandemic by analyzing the influence of subjective health status, changes in daily life owing to COVID-19, COVID-19 fear, and both institutional and interpersonal trust on depression in the context of COVID-19.
First, when examining the experience of depression among individuals who had been quarantined after the outbreak of COVID-19, it was found that 9.1% of all study participants experienced feelings of depression that were significant enough to interfere with their daily lives for a continuous period of at least two weeks within a year. Among the respondents in this study, 4.9% experienced symptoms of depression.
Among the sociodemographic variables, only age was significantly related to depression. Conversely, sex and home income were not related to depression. This study showed that depression levels decreased as age increased, thereby supporting existing research that the increase in depression levels among younger individuals during the COVID-19 period [29, 32]. Economically active younger individuals were more vulnerable to depression in situations where the impact of the COVID-19 pandemic had led to unemployment or economic loss. However, previous studies also suggest that individuals over the age of 60 years were vulnerable to depression during the COVID-19 pandemic [41]. Older individuals may become more vulnerable to mental health issues as their lack of proficiency with electronic devices can lead to isolation from external resources due to COVID-19. Although several previous studies have revealed that women are more vulnerable to depression than men, this study did not find a significant correlation. While home income did not show a significant effect on depression in this study, previous research has shown that unemployment and economic loss during the COVID-19 pandemic increased levels of depression [29, 32]. The discrepancy in results may be because of this study measuring average income over a year, not economic loss.
Subjective health status was a significant predictor of depression among individuals who had been quarantined owing to COVID-19. This aligns with existing research, which suggests that negative perceptions of one's health status increased depression during the COVID-19 period [16, 17]. Subjective health status also influences COVID-19 fear, with increased fear noted among those perceiving their health negatively [42]. Particularly, individuals, including older adults who find it difficult to manage their health during isolation may be more vulnerable to depression because of low subjective health status [43, 44]. The difficulty in managing existing chronic diseases and fear of complications owing to COVID-19 may have made individuals more susceptible to depression.
Furthermore, the results indicate that depression levels increase as negative perceptions of changes in daily life because of COVID-19 increase. These results align with previous studies, showing a rise in depression levels when life changes occur because of infectious diseases [1, 20, 45]. During the COVID-19 period, external activities were limited, and it became difficult to maintain social relationships owing to public health measures such as social distancing [6]. Reduced physical activity owing to these limitations could also have made individuals more susceptible to depression [21]. These restrictions on social contact could have led to a decline in physical functioning and contributed to depression, potentially leading to suicidal tendencies [46, 47]. Maintaining non-face-to-face contact through social media can be helpful when it is difficult to have face-to-face social relationships.
The findings of this study also revealed that depression levels among those who had been quarantined during COVID-19 increased as COVID-19 fear rose. These findings are in line with several existing studies that have shown that fear of COVID-19 increases levels of depression during the pandemic [48, 49]. Fear is the most common emotion experienced during an outbreak of a novel infectious disease, and affecting various psychological and behavioral domains [42]. The concept of COVID-19 fear includes not only fear of infection and death, but also fear of being blamed by others, infecting vulnerable family members, and economic loss. Individuals with high COVID-19 fear, who had been quarantined, may have experienced a reduction in their social networks because of blame from others, which, in turn, may have led to self-blame and increased levels of depression. Infection of vulnerable individuals, such as older adults, those with underlying conditions, and weakened immune systems, could have led to severe COVID-19 symptoms and increased risk of death, which could also have increased levels of depression. Therefore, providing continuous and preventive health care services to vulnerable groups seems necessary by identifying the family and cohabitants of those isolated during outbreaks of acute infectious diseases. The fear of economic loss could have also increased depression, as confirmed by previous studies [22, 24]. Although the government had provided various financial support, including disaster relief funds, it seems necessary to continue supporting groups that continue to experience economic loss as COVID-19 persists.
Trust in institutions responding to COVID-19, such as the government, medical institutions, and the media, did not significantly affect the depression levels of quarantined individuals. This is different from previous studies that found that trust in the appropriate response capabilities of institutions reduces depression and anxiety [29, 49]. This study, unlike preceding studies conducted on the general public, focused on quarantined individuals, which may explain different results. Additional research on the relationship between institutional trust and depression among quarantined individuals may be necessary. However, interpersonal trust among individuals quarantined during COVID-19 reduced depression. This is similar to the results of previous studies conducted on the general public, where interpersonal trust reduced stress and anxiety during the COVID-19 period [31]. In situations where COVID-19, an acute infectious disease, is transmitted by close contacts, trust in acquaintances and colleagues to appropriately respond to preventive measures, such as wearing masks and practicing social distancing, seems to have a protective effect against depression during the COVID-19 period.
In summary, in the context of the existing COVID-19 pandemic, factors such as age, subjective health status, changes in daily life because of COVID-19, fear of COVID-19, and trust in others have been identified as significant variables influencing depression among individuals who had been quarantined owing to COVID-19, as confirmed in previous studies on depression among the general population. However, sex, income level, and trust in institutions did not influence depression, which is different compared to studies involving the general population.
This study is significant in that there is a lack of research on depression among the general public who had been quarantined during the initial pandemic situation of COVID-19. Previous studies have identified depression occurring during isolation and the factors affecting it in patients hospitalized and individuals in self-isolation. Conversely, this study can be used as baseline data to understand the characteristics of depression that persist, even after isolation. As the number of individuals with isolation experience rapidly increases because of the prolongation of COVID-19, it is expected to serve as reference material for planning psychological and social interventions for those experiencing depression.
This study has some limitations. Owing to the nature of the CHS, this study could not measure changes in daily life because of COVID-19 and interpersonal trust through multiple questions. In addition, owing to the nature of the original CHS data, it was impossible to distinguish between those hospitalized due to confirmation and those in self-isolation, therefore, the analysis was conducted together. As the impact of hospitalization experience owing to COVID-19 and self-isolation experience on depression may differ, future research should distinguish between those with COVID-19 confirmation experience and those in simple self-isolation to verify the effects of psychological and social factors on depression. Last, further research is needed to examine the effects according to the characteristics and course of isolation experience, as the duration of isolation experience and the period after release from isolation were not verified.