In the COVID-19 pandemic situation, national public health efforts are focused on combating pathogens rather than managing mental and psychological distress . Suicide among adolescents is a serious problem worldwide, and the suicide rate of teenagers is increasing rapidly in South Korea. Therefore, as potential risk factors for the mental health of multicultural adolescents are likely to occur increase due to the COVID-19 pandemic, this study identified their mental health status and analysed factors that affect suicidal tendencies. The main research results are discussed as follows.
During the COVID-19 pandemic, multicultural adolescents were experiencing negative psychological emotions, with 51.9% who felt lonely and 77.7% who had perceived stress. The survey also showed that 24.6% and 9.4% felt depressive mood and unhappiness, respectively. As a result of analysing the same dataset of the 2020 KYRBS, 78.7% of teenagers were reported to perceive more than moderate stress , and 25.2% were reported to have experienced depressive mood , which is similar to the results of our study. According to Ko's findings , the mental health level of adolescents does not differ depending on whether they are multicultural adolescents, which is consistent with our study. However, while 14.1% of non-multicultural teenagers are reported to feel lonely , our study showed that more than half of multicultural teenagers feel lonely, so it is important to understand the cause of their loneliness before developing suicide prevention programs.
A longitudinal study of Americans  found that teenagers who considered committing suicide at the age of 15 were 12 times more likely to commit suicide when they turned 30. This shows that the idea of suicide in adolescence can lead to suicide in adulthood. Therefore, the painful long-term distress they experience should be recognized as a serious social problem. In particular, governments/policymakers should focus on preventing suicide by understanding the characteristics of multicultural adolescents and exploring internal and external environmental impact factors at home and school. The percentage of multicultural adolescents in Korea who contemplated suicide was 15.8% in the 2015 KYRBS data analysis , while the results of our study in 2020 showed a decreased percentage.
However, compared to all the teenagers who participated in the 2020 KYRBS , 10.9% of the adolescents contemplated suicide, 3.6% had made suicidal plans, and 2.0% had attempted suicide, indicating that the percentage of contemplating suicide (9.2%) and suicidal plans (3.1%) among multicultural adolescents is lower than that of all teenagers, but the suicide attempts (2.3%) percentage shows that the number of multicultural adolescents attempting suicide is higher than that of all teenagers. In other words, it can be confirmed that the risk index for attempted suicide by multicultural adolescents during COVID-19 was higher than that of ordinary teenagers. When controlling for other influencing factors, social support was a major factor influencing teenagers’ suicidal thoughts . The social support of primary caregivers, intimacy with neighbours, the number of social support resources, and the unrelated racial social support of teenagers are correlated with a decline in suicidal thoughts . Therefore, early intervention for multicultural adolescents should be made to prevent suicide attempts by establishing a social support system for families, schools and communities.
The factor that commonly affected the suicidal tendencies of multicultural adolescents was sexual intercourse experience. The odds ratios of contemplating suicide, suicidal plans and suicide attempts of multicultural teenagers with sexual intercourse experience were 7.67 times, 5.04 times and 7.10 times those of multicultural adolescents without sexual intercourse experience, respectively. According to an analysis of the KYRBS data from 2014 to 2016 , multicultural teenagers' suicidal thoughts, suicidal plans, and suicide attempts were higher than those of non-multicultural teenagers, and adolescents from multicultural families did not have higher rates of suicidal thoughts and suicidal plans than non-multicultural teenagers without sexual intercourse experience. Considering that sexual intercourse experience is higher in multicultural teenagers [19, 36], school nurses/teachers and mental health experts should recognize sexual experience as an important mediator and should make efforts to analyse negative mental health and prevent suicide by multicultural adolescents with sexual experience. It is also necessary to provide practical education to express sexual self-determination in adolescence when the possibility of sexual experience increases and to establish a multidimensional environment to seek advice and help with undesirable sexual experiences .
Suicidal attempts of teenagers who had been treated by a doctor due to violence were not significantly different from those who had not been treated for violence. According to an analysis of the 2014 KYRBS data , being treated by doctor due to violence was found to be a significant factor of suicidal attempts for Korean teenagers, but it was not noted in multicultural teenagers. However, the 2018 KYRBS data analysis showed that suicide attempts were 7.38 times higher in teenagers who had been treated by a doctor due to violence . According to the 2015 KYRBS data analysis, teenagers were 2.39 times more likely to commit suicide in cases of repeated violence , and the more multicultural teenagers suffered from school violence, the more they thought of suicide . Additionally, according to the 2015 KYRBS data analysis, multicultural teenagers' experience of violence was a very significant factor in suicidal thoughts  and had a significant influence on both suicidal plans and suicide attempts in line with suicidal thoughts . Our results are different from previous studies because only 0.6% of the multicultural teenagers had been treated in a hospital due to violence, and we think our results should be supplemented to respond more specifically to adults who are the subject of violence with the question, "Have you received hospital treatment for violence (physical assault, intimidation, bullying, etc.) by friends, seniors and adults in the past 12 months?" to specifically understand the experience of violence by multicultural teenagers.
There was no significant difference in suicidal tendencies between the adolescents who experienced substance use and adolescents who did not. However, adolescents who experienced substance use in other studies analysing 2020 KYRBS data  had a 2.31 times higher risk of suicide contemplation than those with no experience, and in Jang’s study , the experience of substance use of multicultural adolescents was 3.39 times higher than that of non-multicultural adolescents . Our study showed that multicultural adolescents who were habitual substance users had a low rate at 0.4%, but it is necessary to continue social attention even if there are a few multicultural adolescents with problematic behaviour.
Sex, cigarette and/or e-cigarette use, alcohol use, the perception of getting enough sleep, perceived health status, and perceived household economic difficulty after COVID-19 were not significant factors for suicidal tendencies. However, there were significant differences in sex, cigarette and/or e-cigarette use, and alcohol use in contemplating suicide, the perception of getting enough sleep in contemplating suicide and suicidal plans, and perceived health status in contemplating suicide, suicidal plans, and suicide attempts. This is difficult to interpret as a direct relationship between general characteristics and suicidal tendencies, but through prior studies, it can be inferred that it is related to suicidal tendencies between these variables. A previous study showed a high risk of suicidal thoughts among female students, teenagers who used cigarette and/or e-cigarettes and alcohol, and those with a low perception of getting enough sleep , low perceived health status and alcohol use showed a high risk of suicidal thoughts among multicultural adolescents . After all, the individual and family environments were found to be related to the risk of suicide. Therefore, to reduce the suicidal tendencies of teenagers, an integrated program should be developed and applied to expand health care support projects linked to home-school communities, especially to improve female students' health behaviours, including cigarette and/or e-cigarette use, alcohol use, and sleep problems, and to improve their perceived health status, rather than limiting community programs only in consideration of multicultural characteristics.
The differences in suicidal tendencies according to mental health were significant in depressive mood, loneliness, perceived stress and perceived happiness. In other words, the rate of suicidal tendencies was found to be high when they felt depressed and lonely, perceived stress levels were high, and perceived happiness was low. This suggests that the mental health of multicultural adolescents is a problem that poses a risk of suicidal tendencies in itself, regardless of what other factors mediate it. Therefore, it is necessary to develop a school-based health education and counselling system that is focused on mental health, a step that should be performed first to detect high-risk groups of adolescents with suicidal tendencies at an early stage.
The mental health factor that commonly affected suicidal tendencies (contemplating suicide, suicidal plans, and suicide attempts) was depressive mood. According to an analysis of 2015 KYRBS data, suicidal thoughts of multicultural teenagers increased by 18.87 times as depressive mood increased , and depressive mood was a significant factor in suicidal thoughts, suicidal plans, and suicide attempts . As contemplating suicide, suicidal plans, and suicide attempts are a sequential series, it is necessary to develop specific strategies to identify the causes and situations of depressive mood experienced by multicultural teenagers and focus on the psychology of their sadness and despair to block the connection. Family solidarity buffers the impact of adolescent depression on suicide risk , and living with family members affects suicidal tendencies . It is therefore necessary to recognize the importance of the family, which is the most primary approach, and draw support from families and parents. According to the 2017 Multicultural Adolescents Panel Study , with participants whose fathers were Korean and whose mothers were foreign, the factors that commonly affected the depression of multicultural teenagers in both males and females were self-esteem, social interaction and school life satisfaction. In particular, for boys, depression was higher in those with low family support, poor relationships with their friends, mothers with cultural adaptation stress, and poor perceived health status; for girls, depression was higher in those with parents’ who were indifferent and had negligent parenting. Therefore, depression prevention programs to alleviate suicidal tendencies should be centred on self-esteem, social interaction and school life satisfaction, which are found to be common impact factors for both boys and girls, and can predict the effectiveness of intervention programs if the contents of the interventions vary depending on sex.
Our research, like previous studies [40, 43], showed that contemplating suicide is significantly higher when teenagers often or always feel lonely and are unhappy. In a study of teenagers aged 13 to 15 years and aged 16 to 17 years from 90 countries who attended the Global School-based Student Health Service (GSHS), common bullying or a lack of friends were reported to be associated with suicide accidents and suicide attempts , so interventions that focus on improving social relationships among teenagers are needed. In addition, loneliness is a variable in predicting suicidal thoughts, and hope is a variable that mediates them ; therefore, suicide prevention programs should be developed and applied to help reduce loneliness and increase hope.
Perceived stress was found to be a significant difference in suicidal tendencies but not an impact factor. A previous study showed that the perceived stress of multicultural teenagers explained 25% of suicidal thoughts with depression , while among multicultural teenagers, male students who were stressed from problems with their friends were 2.70 times more likely to commit suicide, and female students under stress from conflicts with their parents were 2.50 times more likely to commit suicide . We believe there will be differences in research results because in the previous study, the subjects were defined as multicultural adolescents whose parents were not born in Korea, while our study defined the mother as a foreigner. In addition, since few teenagers with suicidal tendencies in our study said they had little stress, perceived stress may not have affected their suicidal tendencies. Nevertheless, according to a longitudinal study of teenagers in Canada , in the case of constant stress in childhood, the reported rate of suicidal thoughts in the around the age of 15 was 2.66 times higher than that of those who did not. Considering these results, we cannot rule out the long-term effects of sustained perceived stress on suicidal tendencies. Stress is also a factor that directly affects suicidal thoughts, but it is also a factor that mediates suicidal thoughts through mental health, such as depression and anxiety . Our study and previous studies suggest that further research is needed to identify the mediating effects to explore various variables that affect suicidal tendencies.
Mental health is recognized as an important priority on the agenda of the United Nations (UN)'s Sustainable Development Goals (SDGs). The WHO emphasized the importance of mental health by proposing the Mental Health Action Plan (2013∼2030), which reduces each country's suicide rate by one-third by 2030 in line with the SDGs . Knowing the mental health status of adolescents who will become world leaders in the future and the effects of suicidal tendencies is an important step towards this goal. Our study is meaningful in that it examined the mental health of multicultural adolescents and verified factors that affect suicidal tendencies in the COVID-19 pandemic situation. Our findings are expected to serve as an empirical basis for the development of suicide prevention programs for multicultural adolescents as the COVID-19 outbreak is prolonged. Additionally, the prolonged COVID-19 pandemic may have a significant impact on pre-COVID-19 mental health conditions and may deteriorate rapidly, further studies are recommended for adolescents with pre-COVID-19 psychiatric history.