The Impact of COVID-19 on Psychiatric Health in the Korean Population

Abstract

Coronavirus disease 2019 (COVID-19) has multiple negative impacts on the psychiatric health of both those previously infected and not infected with severe acute respiratory syndrome coronavirus 2. Moreover, the negative impacts of COVID-19 are closely associated with geographical region, culture, medical system, and ethnic background. We summarized the evidence of the impact of COVID-19 on the psychiatric health of the Korean population. This narrative review included thirteen research articles, which investigated the impact of COVID-19 on the psychiatric health of Koreans. COVID-19 survivors were reported to have a 2.4 times greater risk of developing psychiatric disorders compared to members of a control group, and anxiety and stress-related disorders were the most common newly diagnosed psychiatric illnesses. Studies also reported that COVID-19 survivors had a 3.33-fold higher prevalence of insomnia, a 2.72-fold higher prevalence of mild cognitive impairment, and a 3.09-fold higher prevalence of dementia compared to the control group. In addition, more than four studies have highlighted that the medical staff members, including nurses and medical students, exhibit a greater negative psychiatric impact of COVID-19. However, none of the articles investigated the biological pathophysiology or mechanism linking COVID-19 and the risk of diverse psychiatric disorders. Moreover, none of the studies were actual prospective studies. Thus, longitudinal studies are needed to more clearly elucidate the effect of COVID-19 on the psychiatric health of the Korean population. Lastly, studies focusing on preventing and treating COVID-19–associated psychiatric problems are needed to provide a benefit in real clinical settings.

INTRODUCTION

According to the World Health Organization coronavirus disease 2019 (COVID-19) dashboard, the COVID-19 pandemic has resulted in 761,402,282 confirmed cases and 6,887,000 deaths worldwide as of April 2, 2023 [1]. The Korean Disease Control and Prevention Agency (KDCA) has reported that more than 30,829,827 people in South Korea (hereafter “Korea”) have been infected with severe acute respiratory syndrome coronavirus disease 2019 (SARS-CoV-2), which is about 60% of Korea’s total population (51,558,000) [2]. In addition, more than 34,270 people have died due to COVID-19 in Korea. Meanwhile, however, the number of infections or critical cases arising from COVID-19 has shown a decreasing trend. Thus, many countries worldwide have lifted their quarantine orders and social distancing measures [3]. Beginning in April 2023, Korea also lifted all social distancing measures except for mandatory mask-wearing in hospitals.

Previous well-known outbreaks of viral infectious conditions, such as SARS and Middle East respiratory syndrome (MERS), led to diverse negative long‐term impacts. A study showed that SARS survivors exhibited significant impairment of pulmonary function [4]. Both SARS and MERS cause numerous neurological, psychiatric, and psychological complications [5,6]. Likewise, increasing clinical and post-mortem pathological evidence has shown that COVID-19 continues to have significant adverse health effects long after the acute phase of the infection [7].

Increasingly, studies have found that COVID-19 has multiple negative impacts on the psychiatric health of both those infected and not infected with SARS-CoV-2 [8,9]. The exact mechanisms behind these complications are not fully understood, but several potential pathophysiological mechanisms have been proposed. The virus may directly infect neurons, glial cells, or endothelial cells in the brain, leading to inflammation and neuronal damage, which can contribute to psychiatric symptoms [10]. Others proposed that systemic inflammation caused from the virus can affect the brain by crossing the blood- brain barrier or through signaling mechanisms, and the excessive inflammation in the brain can disrupt normal neurotransmission and lead to psychiatric symptoms [11]. In addition, hypoxia and ischemia can damage brain tissue and affect its normal functioning, leading to psychiatric complications [12]. Moreover, the negative impacts of COVID-19 are closely associated with the geographical region, culture, medical system, and ethnicity [13-15]. Therefore, many countries have conducted studies to investigate how COVID-19 impacts the psychiatric health of their population. The purpose of this review was to summarize studies that investigated the impact of COVID- 19 on the Korean population.

DATA SEARCH

We searched PubMed, Embase, Medline, PsycINFO, the Cumulative Index to Nursing and Allied Health Literature, and the Web of Science using the keywords “COVID-19,” “SARS-CoV-2,” “mental health,” “psychiatry,” and “Korea” to identify relevant published articles. We focused on the adult population, so we excluded studies involving children or adolescents. Reference lists from identified articles and reviews were manually searched to find additional studies of interest. Original research papers reporting either the direct impact of COVID-19 per se or its indirect effect due to psychosocial stress were included in our review. However, we did not include review papers. The language of all papers was restricted to English.

S.M.W. and Y.S.W. initially reviewed the abstracts identified from the literature search independently to determine whether they met the scope of our review. Two other authors (S.W.K. and H.K.L.) then re-evaluated the papers to confirm whether they clearly met the selection criteria. If a disagreement occurred, the article in question was discussed, and a consensus was reached following review by the three remaining authors (W.S.C., W.M.B., and C.U.P.). This article is a narrative review focusing on the impact of COVID-19 on the psychiatric health of the Korean population. Based on a consensus among the authors, all relevant studies meeting the scope of our paper were selected. As a narrative review paper, the study did not involve primary data collection or human subjects, thus an Institutional Review Board (IRB) approval was not required.

RESULTS

The literature search resulted in 13 research articles that had investigated the impact of COVID-19 on the psychiatric health of Koreans. The selected studies were very heterogeneous in their design, settings, subjects, and outcome measures. Thus, we first subdivided them into the following groups: 1) those studies that included general populations (Table 1) and 2) those studies that included special populations, such as medical staff members, immigrants, or patients with cancer (Table 2).

Table 1.

Summary of published articles investigating impact COVID-19 in psychiatric health in general population

Study	Design	Sample size	Outcome measures	Key results
1.Nationwide cohort study
Park et al., 2021 [17]	Case control study	260,883	Newly registered ICD-10 codes for psychiatric disorder	Higher prevalence of psychiatric illness in COVID-19 survivors than control (12.0% vs. 7.7%, odds ratio = 2.40) Anxiety and stress-related disorder was most common
Park et al., 2021 [18]	Case control study	299,968	Newly registered ICD-10 codes for insomnia disorder	3.33-fold higher prevalence of insomnia disorder in COVID-19 survivors than control
Park et al., 2021 [20]	Case control study	306,577	Newly registered ICD-10 codes for dementia	1.39-fold higher prevalence of dementia in COVID-19 survivors than comparators
Kim et al., 2022 [21]	Case control study	288,197	Newly registered ICD-10 codes for MCI and dementia	Risk of developing dementia and MCI was higher in COVID-19 positive group than in COVID-19 negative group (HR: 2.72 & 3.09)
2.Infodemiology data
Cha and Jeon 2022 [24]	Relative search volume study	NA	Interests in sleep problems	Searches for insomnia-related keyword significantly increased initially which fell back down. However, the search showed continuous increment in age > 60
3.Forecasting model
Ryu et al., 2022 [29]	Facebook Prophet	53,127	Compared suicide deaths before and after COVID-19	Total numbers of suicides during COVID-19 did not deviate, or did not increase more than expected, from the expected projections. However, suicides among women and age < 34 significantly exceeded the expected level
4.Retrospective chart review
Lee et al., 2022 [2]	Single center chart review	519	Compared demographics of suicide attempters before and after COVID-19	Rate of suicide attempts by women increased from 60.1% vs. 69.3% and those with previous psychiatric illness from 63.4% to 72.9%

COVID-19, coronavirus disease 2019; ICD-10, International Classification of Diseases 10th Revision; MCI, mild cognitive impairment; NA, not applicable; HR: hazard ratio.

Table 2.

Summary of published articles investigating impact COVID-19 in psychiatric health in special populations

Study	Design	Subjects	Sample size	Outcome measures	Key results
Kim et al., 2022 [32]	Cross-sectional observational	Medical students in clinical clerkship	179	PSS	3rd-year student (1st year clerkship) had lower average PSS than 4th-year student (2nd year clerkship)
Lee et al., 2022 [34]	Cross-sectional study	Medical students	270	Impact of Event Scale-Revised	10.4% of students were COVID-19–related PTSD risk group
Bae et al., 2022 [37]	Consensual qualitative research method	Health care workers who experienced cohort isolation	50	Diverse psychological distress	High psychological stress including guilt and physical as well as emotional exhaustion
Kim et al., 2022 [38]	Anonymous online survey	Nurses working in the COVID-19 inpatients wards	136	Stress and Anxiety to Viral Epidemics-9 scale	30.1% and 40.4% had depression of work-related anxiety
Acharya et al., 2022 [41]	Cross-sectional quantitative study	COVID-19 negative immigrants	386	Generalized anxiety disorder 7-item scale	42.7% experienced severe anxiety. Higher anxiety was associated with history of psychological event, higher age, social relief funds, and working conditions
Kim et al., 2022 [43]	Anonymous online survey	Patients with cancer	221	Diverse scales reflecting psychiatric health	43.0% reported disruptions in healthcare service utilization during COVID-19 pandemic. High levels of depression, anxiety regarding viral epidemic, fear of COVID over cancer, and low resilience were associated with functional impairment due to psychiatric health

COVID-19, coronavirus disease 2019; PSS, perceived stress scale; PTSD, post-traumatic stress disorder.

General Population

Nationwide cohort study

Ever since the Korean government created and opened the National Health Information Database, which consists of healthcare data including health screening results, sociodemographic variables, and mortality for the whole Korean population, a growing number of studies have used this database to conduct nationwide cohort studies [16]. The Korean government also further created the National Health Insurance Service (NHIS) COVID-19 database, which has aimed to promote COVID-19-related medical research in cooperation with the KDCA [17]. The NHIS COVID-19 database contains comprehensive data for the following three groups: a COVID-19-positive group, a control population, and polymerase chain reaction (PCR)- negative tested individuals. Subsequently, multiple studies using the above database have been conducted to understand both the acute and chronic complications associated with COVID-19.

Four nationwide cohort studies investigating the impact of COVID-19 in psychiatric disorders were identified. The first study, by Park et al. [17], showed that COVID-19 survivors in Korea have a greater risk of developing psychiatric illness compared to the rest of the population. A total of 260,883 individuals aged ≥ 20 years were included in their study. Individuals who tested positive for COVID-19 by PCR and then were discharged from the hospital after treatment and those who tested positive for COVID-19 by PCR and then recovered from their infection without hospitalization were defined as COVID-19 survivors. This study excluded those with a previous history of psychiatric illness up to December 31, 2019, to focus on cases of psychiatric disorders that newly developed in 2020. The primary endpoint of this study was the development of psychiatric illness defined using newly registered Interna-tional Classification of Diseases 10th Revision (ICD-10) codes for psychiatric disorders, including non-affective psychotic disorders (F20−24 and F28−29), affective psychotic disorders, (F25, F30−31, F32.3, and F33.3), anxiety and stress-related disorders (F40−48), alcohol or drug misuse (F10−16 and F18−19), mood disorders without psychotic symptoms (F32−34 and F38−39, excluding F32.3 and F33.3), eating disorders (F50), and personality disorders (F60−63 and F68−69) from January 1 to December 1, 2020. Among them, COVID-19 survivors totaled 6,148 (2.36%) and 254,735, and 20,262 (7.8%) study participants were diagnosed with psychiatric illness, with anxiety and stress-related disorders being the most common newly diagnosed psychiatric illness (13,736; 5.3%). The logistic regression analysis, after adjusting for covariates, showed that COVID-19 survivors had a 2.40- fold greater risk of developing psychiatric disorders than participants in the control group (odds ratio, 2.40; 95% confidence interval, 2.21−2.61; p < 0.001).

The same group of researchers also analyzed the prevalence and associated factors of insomnia among COVID- 19 survivors [18]. The study in question compared 6,934 COVID-19 survivors with 292,764 control group participants and found that COVID-19 survivors had a 3.33- fold higher prevalence of insomnia han the control group. The same study further showed that the risk of insomnia among COVID-19 survivors with no specific treatment and that among survivors who received specific treatments, including supplemental oxygen therapy and mechanical ventilation, were 3.16-fold and 3.89-fold, re-spectively. Since insomnia is one of the most important post-intensive care syndromes, COVID-19 survivors who required oxygen support may develop insomnia or another post-intensive care syndrome [19]. On the other hand, the risk of insomnia among COVID-19 survivors with no specific treatment was also high, suggesting that the occurrence of insomnia stems not only from receiving intensive care but also having COVID-19 itself.

Another nationwide cohort study, which used the same NHIS COVID-19 database, showed that COVID-19 survivors have a higher risk of dementia compared to other populations in South Korea [20]. The study enrolled 7,133 survivors of COVID-19 and 299,444 comparator subjects who either tested negative for COVID-19 (PCR-negative group) or were not tested for COVID-19 (control group). This 6-month retrospective study showed that the incidence of dementia among COVID-19 survivors was 1.39 times greater than that in the comparator group (PCR-negative group + control group). The same study also showed that COVID-19 survivors who were hospitalized for COVID-19 displayed a 1.62-fold higher incidence of dementia compared to the comparator group.

The last nationwide cohort study of interest also investigated the association between the risk of dementia and COVID-19 [21]. This study also subdivided the comparator group into PCR-negative and control groups. This study enrolled subjects during the 4 months between February 1, 2020 and May 31, 2020 (the early period of the pandemic in Korea), who were not diagnosed with dementia or mild cognitive impairment in the past 5 years and divided them into 3 groups, as follows: 1) those who tested positive for COVID-19 (COVID-19–positive group, n = 7,426), 2) those who tested negative for COVID-19 (COVID-19–negative group, n = 199,252), and 3) those who were not tested for COVID-19 (control group, n = 81,519). The risk of developing dementia and mild cognitive impairment (MCI) was higher in the COVID-19–positive group than in the control group with hazard ratios of 2.72 and 3.09, respectively. Interestingly, the risk of developing dementia was also greater in the COVID-19–negative group compared to the control group, with a hazard ratio of 2.89, which was comparable to that of the COVID-19–positive group.

Infodemiology data

Studies conducted outside of Korea showed that around 35.7% of the general population experienced sleep problems during the first 8 months of the COVID-19 pandemic [22,23]. Cha and Jeon [24] investigated the effects of the COVID-19 pandemic on sleep-related problems in adults, including elderly individuals, using infodemiology data. Examining internet search data can be a very powerful way to investigate public health responses to certain social events, such as the COVID-19 pandemic [25]. One method of analyzing internet search data is to use the relative search volume (RSV) [26]. RSV data are known to reflect the number of searches performed over a certain period. Cha and Jeon [24] used data from NAVER, which is the most used search engine in Korea, because it offers a NAVER Trends service that provides RSV data. The study compared the general population’s interests in sleep pro-blems such as insomnia, other sleep disorders, and sleeping pills and their side effects between the period before COVID-19 (T0), the pandemic’s onset to 7 months after (T1), 7−14 months after (T2), and 14−21 months after (T3), respectively. The results showed that searches using insomnia-related keywords significantly increased in number from T0 to T1, then significantly decreased from T1 to T2 and from T2 to T3. Interestingly, different patterns were noted for those aged 19−59 and ≥ 60 years, re-spectively. Meanwhile, search terms related to other sleep disorders as well as sleeping pills and their side effects in those ≥ 60 years of age showed a continuously increasing trend from T0 to T3. The study authors hypothesized that the difference in patterns by age group is attributable to a slower recovery from the psychological impact of the pandemic with increasing age (i.e., lower resilience) among older adults [27,28].

Forecasting model using Facebook Prophet

Ryu et al. [29] used a unique study design to compare suicide deaths between before and after the onset of the COVID-19 pandemic in Korea. Their study used Facebook Prophet to generate a forecasting model and compared suicide deaths in Korea between 1997 and 2018, and the authors predicted the expected numbers of suicide deaths in 2020 thereafter. They then compared the expected number of suicides and the true number of suicides that occurred in 2020. The results showed that the total number of suicides during the COVID-19 pandemic did not deviate from what was expected; however, the number of suicides among women and those < 34 years of age significantly exceeded the expected quantity, which suggests that women and younger individuals were more vulnerable to suicide during the early COVID-19 pandemic.

Retrospective Chart Review

A retrospective study investigated vulnerable indivi-duals and the characteristics of changes in suicidal behavior during the COVID-19 pandemic [2]. This study reported similar findings to those of the forecasting model study done by Ryu et al. [29] and showed that women and people with previous psychiatric illnesses were more vulnerable to suicide attempts during the COVID-19 pandemic. The study retrospectively reviewed the medical records of 519 patients with suicide attempts (n = 303 pre-pandemic vs. n = 270 post-pandemic) who visited the emergency department from February 2019 to January 2021. The results showed that the proportion of suicide attempts increased among women from 60.1% to 69.3% (p = 0.035) and among those with previous psychiatric illness from 63.4% to 72.9% (p = 0.006).

Special Populations

Healthcare workers, including medical students

The COVID-19 pandemic not only affected the psychiatric health of general populations but also had a negative impact on healthcare workers and medical students in Korea. In fact, physicians and healthcare professionals experienced intra-pandemic psychiatric health problems more frequently and seriously than the general population [30,31]. At least four studies have been conducted to investigate the impact of COVID-19 on mental health–related symptoms in healthcare workers, including medical students.

Kim et al. [32] studied the perceived stress and perceptions regarding clinical clerkship among incoming clinical students (third years) and senior clinical students (fourth years) during the COVID-19 pandemic. Their study, which had a cross-sectional observational design, involved third-year (n = 110) and fourth-year (n = 69) clinical phase medical students at a private medical college located in Korea. The perceived stress scale (PSS) was used to assess the students’ perceived stress levels regarding the COVID-19 pandemic [33]. The results showed that the average PSS score of the entire sample was 14.63 (standard deviation, 6.31) points, and the students identified as having low, moderate, and high levels of COVID- 19–related stress totaled 44.1%, 53.6%, and 2.2%, re-spectively. Interestingly, the third-year students had significantly lower average PSS scores than the fourth-year students. Likewise, the majority of third-year students were classified as having low stress, while the majority of fourth-year students were classified as having moderate stress. The difference according to year could be attributed to the fact that the third-year students had no clinical experiences before the survey, while the fourth-year students had experienced intra-pandemic core clerkships in the previous year (2020). Thus, the perceived stress could be higher when the duration of clinical experience with COVID-19 patients was longer.

Another study by Lee et al. [34] investigated the sociodemographic and psychosocial factors associated with the risk of COVID-19–related post-traumatic stress disorder (PTSD) among medical students. This cross-sectional study included 270 medical students (including pre-medical first-year, medical first-year, and medical third-year students) of a public medical college located in Korea. All participants completed the Korean version of the Impact of Event Scale-Revised to assess their PTSD symptoms [35], and the results showed that, in 2021, 10.4% of students could be classified into the COVID-19–related PTSD risk group. The study further showed that students in lower grades (especially first-year medical students) and current smokers had higher COVID-19–related PTSD risk levels. Meanwhile, students with greater resilience, self-esteem, and social support were less likely to have a high COVID-19–related PTSD risk.

Multiple studies have shown that cohort isolation has a negative impact among both patients and medical staff members [36]. One study by Bae et al. [37] investigated healthcare workers’ perceptions of difficulties due to the specificity of a psychiatric hospital, difficulties due to cohort isolation, and difficulties related to external factors. In Korea, the usual protocol of the active monitoring period is 2 weeks, but, in a psychiatric hospital, the isolation for this cohort lasted 51 days because new COVID-19–positive cases were continuously being identified. As a result, 232 of 613 patients and 50 of 173 healthcare workers were isolated within the hospital. The study showed that a lack of protocols and non-compliance with quarantine guidelines were some of the important stressors that the healthcare workers were subjected to. Furthermore, workforce shortages, physical problems, fear of infection, limited facilities, guilt toward newly confirmed cases, exhaustion, and distress caused by separation from family were important aspects of difficulties related to cohort isolation itself. The negative stigma and frequent administrative orders given by the government also caused significant distress. The major impact of the study is that, when the cohort isolation is extended, it is important to look at the psychiatric and psychological well-being of not only patients but also healthcare workers.

The last study of interest more specifically investigated psychiatric distress among nursing professionals working in the COVID-19 inpatient wards [38]. This study included a total of 136 nurses working in the COVID-19 inpatient wards at Asan Medical Center, who completed an online survey from April 7−18, 2022. This was about 2 months after the Center for Infection Control of Korea was opened at Asan Medical Center (in February 2022), which was the first private hospital to operate a separate facility wholly dedicated to infectious diseases. The results showed that 30.1% and 40.4% of nursing professionals working in COVID-19 inpatient wards were rated as having depression or high levels of work-related stress and anxiety responses to COVID-19. The study did not investigate the work-productiveness or work-efficiency decrement among these nursing professionals due to their heightened depressive symptoms and anxiety. However, it is self-evident that psychiatric distress might have various negative impacts among those helping critically ill COVID-19 patients.

Immigrants

According to the Korean Ministry of Justice, more than 2,450,000 foreigners currently live in Korea, including 1,688,855 who are long-term residents [39]. It is self-evident that the burden and seriousness of COVID-19 already pose a risk to immigrants [40]. Thus, Acharya et al. [41] conducted a study and highlighted the levels of anxiety among the immigrant population attributable to the COVID-19 pandemic using the GAD-7 tool. A total of 386 immigrants in Korea were included, and the prevalence of severe anxiety among immigrants was found to be 47.2%. Interestingly, female immigrants (28.6%) had less anxiety than male immigrants (71.4%). Higher anxiety was associated with a history of chronic and psychological events, older age, the receipt of social relief funds, and working conditions. However, none of the subjects included had a history of COVID-19. Thus, the study was only able to investigate the psychosocial impact of COVID-19 on psychiatric health rather than the biologi-cal impact.

Cancer patients

People receiving treatment for cancer compose one of the major groups experiencing a negative impact from COVID-19. Directly, the COVID-19 pandemic has led to higher rates of morbidity and mortality in patients with cancer [42]. More specifically, in the era of the COVID- 19 pandemic, cancer care utilization changed rapidly due to the shortage of medical personnel, hospital beds, and personal protective equipment (e.g., masks, gowns, and gloves). The psychiatric and psychological distress experienced due to treatment delay or non-adherence also had negative impacts on the physical, social, and psychiatric well-being of these patients. Kim et al. [43] investigated the functional impairments in psychiatric health and explored their relationships with depression, anxiety regarding the viral epidemic, and disruption in healthcare service utilization among cancer patients due to COVID-19. These authors used online surveys to pose questions related to the disturbances faced by patients with cancer in utilizing healthcare services in the pandemic era to 221 patients with different cancers. The results showed that 43.0% (n = 95) of respondents reported disruptions in healthcare service utilization during the COVID-19 pandemic, and high levels of depression, anxiety regarding the viral epidemic, fear of COVID-19 over cancer, and low resilience were associated with functional impairments in psychiatric health.

DISCUSSION

The purpose of this review was to provide a narrative of published articles that investigated the impact of the COVID-19 pandemic on the Korean population. A total of 13 research articles were included in our review. The studies consistently showed that COVID-19 had a negative impact on the psychiatric health of the general population, medical staff members, immigrants, and patients with cancer. COVID-19 was reported to have diverse negative impacts on psychiatric health, which include depression, anxiety, sleep problems, suicide attempts, the risk of dementia, PTSD, and others. COVID-19 survivors were reported to have a 2.40-fold higher risk of developing psychiatric disorders than individuals in a control group, and anxiety and stress-related disorders were the most common newly diagnosed psychiatric illnesses [17]. COVID-19 survivors also had a 3.33-fold higher prevalence of insomnia [18], a 2.72-fold higher prevalence of MCI, and a 3.09-fold higher prevalence of dementia than the control group [21]. More than four studies highlighted that medical staff members, including nurses and medical students, showed even greater negative psychiatric impacts from COVID-19.

One interesting finding of this review effort was that we were able to identify diverse articles that used novel research designs. Four studies used the NHIS COVID-19 database, which is a unique database including comprehensive real-world data generated by the KDCA [17]. Infodemiology data or internet search data analyses using relative search volumes were used to understand how the general population’s interest in sleep changed after the COVID-19 pandemic started [24]. Other investigators used Facebook Prophet to generate a forecasting model and compared suicide deaths between before and after the COVID-19 pandemic [29]. Another research paper specifically investigated psychiatric distress among nursing professionals working in the COVID-19 inpatient wards [37], while a different study included healthcare workers who experienced prolonged cohort isolation [21].

Notably, none of the surveyed articles included investigated the biological pathophysiology or mechanisms linking COVID-19 and the risk of diverse psychiatric disorders. Likewise, unlike the global research trend, we were not able to find translational research or studies linking clinical findings with basic research. Moreover, none of the studies were actual prospective studies. Thus, longitudinal studies are needed to more clearly elucidate the effect of the COVID-19 pandemic on the psychiatric health of Koreans. Lastly, studies focusing on the prevention of and management of COVID-19-associated psychiatric problems are needed for implementation in real clinical settings.

Funding Statement

Funding This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MIST) (No. 2022R1A2C109321512).