The novel coronavirus disease 2019 (COVID-19) has been declared a pandemic by the World Health Organization (WHO) in March 2020. Owing to the rapid spread of the disease worldwide, the number of infected individuals and related deaths is continuously rising drastically [1]. The devastation of the COVID-19 pandemic has inevitably affected the lives and health of numerous people, including various mental health problems [2]. Increases in the prevalence of psychological disorders during a pandemic are common; studies estimated that up to one-half of the population is vulnerable to experience such disorders [1]. Likewise, mental health deterioration and depression due to the COVID-19 outbreak have been reported in many countries [3]. Similar tendencies are shown in South Korea as many residents report higher levels of depression, anxiety, stress, and psychosis risk than before the pandemic [4]. Moreover, Korea has an exceptionally high suicide rate, which is associated with depression. Therefore, identifying the risk factors for depression and implementing appropriate preventive measures during the pandemic is essential [5].

Given that exposure to persistent risk and the uncertainty of infectious diseases can escalate risk of depression, the ability to stay at home and rest under times of COVID-19 symptom manifestation may be a relevant factor to investigate [6]. Psychological responses to pandemic outbreaks may be a result of various factors, including disruptions in daily routines, social isolation, deficiencies in daily necessities, school closures, and occupation related vulnerabilities such as salary deduction [7]. Vulnerability arising from employment is also a highly correlated factor because COVID-19 related phenomenon, such as the social lockdowns ordered by many governments, have had a substantial impact on the economy and caused escalations in unemployment [8]. In fact, a large body of literature reveals that involuntary unemployment can have a lasting impact on mental health, including depression [9].

As policies on COVID-19 strongly prioritize case isolation and quarantine, requiring symptomatic individuals to undergo home isolation, the ability to rest at home in the case of experiencing disease related symptoms may be associated with risk of depression [10]. Many countries rely on comprehensive containment policies involving social distancing and the isolation of suspected or confirmed cases whilst vulnerable groups may be more susceptible to being unable to rest despite symptom appearance [11,12]. Korea has also introduced social distancing and quarantine measures to manage the spread of COVID-19. At the same time, symptoms of acute COVID-19 symptoms have been associated with depressive symptoms, implying the importance of this subject in terms of mental health in times of the pandemic [13].

This study aimed to investigate the relationship between ability to rest at home if coronavirus symptoms appeared and depressive symptoms, using nationally representative data. We hypothesized that individuals who could not rest at home despite the appearance of suspected coronavirus symptoms were more likely to display depressive symptoms. Additional analysis was conducted to determine the reasons for the inability to rest at home.

Table 1 presents the general characteristics of the study’s participants. Of the 225,744 participants, 6,354 (2.8%) had depressive symptoms. Depressive symptoms were more common in participants who responded that they could not rest at home (4.1%) when experiencing COVID-19-related symptoms than those who could (2.7%). Depressive symptoms were also more prevalent in lower-income groups than in higher-income groups. The percentage of participants with depressive symptoms decreased in a stepwise manner with each income level group. With regard to individuals who could not rest at home, the population distribution for each reason behind not being able to rest can be found in Supplementary Table 1(in the online-only Data Supplement).

Table 2 reveals the association between depressive symptoms and ability to rest at home if COVID-19 symptoms appeared. Compared to individuals who could rest, those who could not (OR 1.53, 95% CI 1.34-1.74) were more likely to have depressive symptoms. The additional analysis on the reasons for not resting at home is shown in Table 3. Higher odds of depressive symptoms were found in participants who could not rest because of work (OR 1.50, 95% CI 1.30-1.74), the need to purchase daily necessities (OR 2.40, 95% CI 1.15-5.03), and other reasons (OR 1.64, 95% CI 1.19-2.24), than those who could rest at home if they experienced symptoms.

Table 4 shows the results of the subgroup analysis conducted based on income level. The general tendencies of the main findings were maintained regardless of income level, which infers that the inability to rest at home in case of the emergence of COVID-19 symptoms is related to significantly higher odds of depressive symptoms in all income groups. However, the magnitude of this association was relatively higher among participants belonging to the low (OR 2.03, 95% CI 1.35-3.05) than the middle-low (OR 1.39, 95% CI 1.10-1.75), middle-high (OR 1.56, 95% CI 1.24-1.96), and high (OR 1.58, 95% CI 1.24-2.01) income groups.

This study is the first to establish an association between the inability to rest at home if COVID-19-related symptoms manifested and increased depressive symptoms, using nationally representative data from Korea. The study’s findings revealed that depressive symptoms were more likely in participants who could not rest at home due to work or the need to purchase daily necessities. The association between depressive symptoms and ability to rest at home if COVID-19 symptoms emerge during the pandemic was significant in all income groups—the magnitude of this relationship being strongest in the low-income group. The study results offer important insights, because many countries have adopted COVID-19 containment policies focusing on social distancing and suspected or confirmed case isolation. However, studies showed that lasting pandemics increase the general population’s vulnerability to depressive symptoms [19]. The analyses of this study demonstrated that addressing potentially disadvantaged individuals who cannot rest at home despite suspicion of COVID-19 infection may be necessary in managing and mitigating depression during times of infectious disease outbreaks.

The reasons for the inability to rest at home, even while experiencing COVID-19 symptoms, can be diverse. These reasons included work-related responsibilities, the need to purchase daily necessities, and the need to care for family members or friends. Based on this study’s result, it can be concluded that the inability to stay at home because of work or having to purchase daily necessities was related to depressive symptoms. Regarding work-related reasons, occupational insecurity and financial concerns due to the COVID-19 outbreak have been associated with greater depressive symptoms [20]. Specifically, individuals with perceived job insecurity had a higher likelihood of depressive symptoms. Additionally, individuals with financial stress reported a twofold increase in the risk of showing clinically depressive symptoms [21]. In contrast, having a job to return to and the ability to take paid leave during the outbreak had significant mental health benefits [8]. Currently, the Korean government requires individuals to self-monitor for COVID-19 symptoms, isolate themselves, and get tested upon symptom development. Under such circumstances, being unable to stay at home due to work may suggest job insecurity or experiences of financial constraints, which can increase the risk of depressive symptoms.

Likewise, individuals needing to purchase daily commodities during the outbreak may be from a relatively disadvantaged group, such as adults living alone. This is an important factor to investigate because a previous survey revealed that the most common reason to go outside despite being requested to stay at home during the COVID-19 outbreak was to buy food [22]. Studies have shown that person-to-person contact is essential for maintaining positive emotions, and living alone can increase the risk for poor well-being [23]. Marital status has also been reported to correlate with psychological distress, with married people showing lower levels of distress than single individuals during the pandemic [24]. Additionally, social isolation may escalate the risk of food insecurity and nutritional insufficiency, which play a significant role in the psychological health of older adults [25]. Based on these results, there is a need to address the identified group of individuals who may be vulnerable to depressive symptoms during the pandemic.

The relationship between the inability to rest at home and depressive symptoms during the COVID-19 outbreak was maintained regardless of income level, with the strongest degree of correlation being present in the lowest income group. This result suggests that ability to stay at home in case COVID-19 symptoms appeared is an influential factor for depressive symptoms, which merits attention because of the extent of the resulting psychological distress [4]. Acute COVID-19 symptoms are also known to have a bidirectional relationship with depressive symptoms, emphasizing the importance of this factor in addressing mental health during the pandemic [13]. Moreover, further emphasis should be placed on lower-income groups because the socioeconomically disadvantaged are likely to experience disproportionately higher risks of mental illnesses when disruptive, traumatic events occur [26].

This study has several limitations. First, causal relationships cannot be confirmed because the data used were cross-sectional. Second, the interesting variable of this study was measured based on self-reports only. Additionally, some participants did not provide specific reasons for their inability to remain at home; instead, they chose the ‘other reasons’ option. Third, respondents may have participated at different peak times of the COVID-19 pandemic as the number of infected patients continuously fluctuated. Last, the fact that reasons for not being able to stay at home during the pandemic may differ depending on age needs to be considered when interpreting the study results [27]. Despite the limitations stated above, this study is important because it is the first to investigate the relationship between the inability to rest at home in the case of COVID-19 symptom appearance and depressive symptoms. The findings are also significant because the data consisted of a large, nationally representative sample of the general population surveyed during the COVID-19 crisis.

In conclusion, inability to rest at home in the case of COVID-19 symptom manifestation was associated with higher depressive symptoms. Specifically, an increased likelihood of depressive symptoms was found in participants who reported work-related responsibilities or the need to purchase daily necessities as reasons for their inability to stay home. The tendencies of the general findings were maintained regardless of income level, with the lowest income group showing the most significant degree of association. The findings suggest the need to address the identified vulnerable group of individuals in mitigating the mental health consequences of the pandemic.