INTRODUCTION
According to the suicide rate statistics of the Organization for Economic Co-operation and Development (OECD) for the years 2018-2020, South Korea faces a significant issue with the suicide rates, ranking first among the 42 OECD member nations [
1]. While this ranking predominantly reflects the broader population and not specifically adolescents, this problem is particularly acute among younger age groups. This is highlighted by the Causes of Death Statistics in 2022 from the Statistics Korea, reporting suicide as the leading cause of death among Korean adolescents for 10 consecutive years [
2]. Adolescence represents a period of rapid physical and psychological changes, and adolescents may experience emotional difficulties owing to such changes, which can sometimes lead to suicide attempts. Despite ongoing efforts in suicide prevention, the suicide rate among Korean adolescents continues to rise, exacerbated by the impact of the coronavirus disease-2019 (COVID-19) pandemic [
3]. This sustained increase underscores the necessity for a multidimensional understanding of suicidality among adolescents.
Adolescent suicide often results from complex interactions among various factors. It encompasses intricate thoughts or behaviors rather than being solely the consequence of a single actions [
4]. Therefore, behavioral aspects related to suicide, including suicidal thoughts, plans, and attempts, as well as various psycho-emotional characteristics of adolescents should be examined to identify whether they are associated with suicidality [
5]. Many studies have focused on analyzing the reasons for attempting a suicide as well as psycho-emotional variables, such as depression, anxiety, sadness, and hopelessness, as indicators, in addition to suicidal thoughts, plans, and attempts, to differentiate suicidality classes among adolescents [
5-
7]. Although not included for differentiating suicidality classes in previous studies, the present study intended to focus on loneliness, which is considered another risk factor for suicide. Loneliness can be defined as a quantitative or qualitative lack of a social relationship network [
8,
9], which is reportedly associated with both suicidal thoughts and behavior [
10,
11].
Most previous studies on factors that influence the differentiation of suicidality classes have analyzed the influence of specific factors or focused on the psycho-social characteristics of adolescents. For example, some studies have examined the influence of the experience of child sexual violence on suicide behavior patterns [
12] and psycho-social variables, such as impulsivity, self-esteem, self-harm, abuse experience, and deviant behavior, as predictors for differentiating suicide behavior patterns [
6]. Another study examined sex, academic grades, sex identity, and self-perceived overweight as factors for predicting suicidality population [
7]. The present study examined variables that showed a significant association with suicide behavior for comprehensive consideration of how health behavior factors, including activities of daily living (ADLs), of adolescents discussed in existing studies can influence the suicidality among adolescents. Studies have reported that dietary habits and physical activities have a significant influence on depression and suicidal thought [
13-
15]; school victimization increases the likelihood of suicidal thought and attempt [
16,
17], and sexual activity experience, smoking, and drinking are significant influencing factors that increase depression, suicidal thought, and suicidal attempts [
18]. Based on the predictors identified in existing studies, dietary habits (breakfast status and frequency of eating fast foods), physical activities (high-intensity activities, moderate-intensity activities, muscle strengthening exercises, walking, and physical exercises [PEs]), violence victimization experience, sexual activity experience, deviant behavior (smoking, and drinking), and general characteristics (sex, year in school, grades, and household income) were included as influencing factors for differentiating suicidality classes.
In the present study, latent class analysis (LCA) was used to differentiate suicidality classes among adolescents and prepare interventions specialized for each class. LCA is based on a person-oriented approach, and its subgroups are derived by analyzing the response patterns of individuals. This approach offers the advantage of analyzing heterogeneity within individuals that remains undetected in variable-centered analysis.
Accordingly, this study aimed to explore adolescent suicidality by examining suicidal thoughts, plans, and attempts, and psycho-emotional factors such as sadness/hopelessness and loneliness, thus broadening the understanding of suicidality. It focused on health-behavior factors, including ADLs, to predict suicidality classes among adolescents and provide data for customized intervention methods in suicide prevention education. The research questions are: “How many latent classes of suicidality exist among adolescents?” and “What factors influence these classes?”
DISCUSSION
The present study derived the latent classes of suicidality among adolescents and examined the influence of adolescents’ health behaviors (dietary habit, physical activities, violence victimization experience, sexual activity experience, and deviant behavior), academic grades, household economic status, sex and year in school on the latent classes.
Suicidality among adolescents was classified into three latent classes: active suicidality (n=2,486; 4.8%), passive suicidality (n=12,179; 23.5%), and non-suicidality (n=37,185; 71.7%) classes. The active suicidality characteristically showed high scores for sadness/hopelessness, loneliness, suicidal thought, suicidal plan, and suicidal attempt. The passive suicidality showed similar levels of sadness/hopelessness and loneliness and relatively lower suicidal thought as compared to those of the active suicidal ideation class and low levels of suicidal plan and suicidal attempt as compared to those of the non-suicidal ideation class. Interestingly, two classes vulnerable to suicidality were identified, and there were differences in the level of risk between the two classes. The participants belonging to the active suicidal ideation class had a higher suicidality as they showed the highest likelihood of suicidal plan and attempt. Accordingly, active intervention for suicide prevention is needed for adolescents who belong to this class. In contrast, the participants belonging to the passive suicidal ideation class had low likelihood of suicidal plan and suicidal attempt but still showed high levels of sadness/hopelessness, loneliness, and moderately elevated levels of suicidal thought. Therefore, emotional and psychological intervention and assessment and continued monitoring of the possibility of worsening suicidality are needed for adolescents belonging to this class.
Second, examination of factors that influence the classification of latent classes of suicidality showed that violence victimization experience, sexual activity experience, deviant behavior (smoking and drinking), household income, sex, and year in school were all identified as factors with significant influence on the classification of latent classes. With respect to specific factors, dietary habit was found to have an influence in differentiating between non-suicidal and passive suicidality and between non-suicidal and active suicidality. The results also showed that adolescents who skipped breakfast or ate fast foods more often were relatively likely to be vulnerable. Such findings were consistent with those of previous studies reporting that unhealthy dietary habit is highly associated with neurosis [
28,
29]. Therefore, applying specific and systematic programs for improving dietary habits should be helpful for these adolescents. Such programs should include education that emphasizes the importance of regular meals and provision of well-balanced diet, which can be expected to contribute to improving mental health and reducing suicidality among adolescents.
Among physical activities, walking exercise and frequency of exercise during PE class were factors that should be examined with greatest importance among the findings in the present study. This is because these were factors that influenced the differentiation of the two classes that were identified as suicide risk classes. The findings showed that adolescents with less walking exercise and lower frequency of exercise during PE class were more likely to belong to the active than the passive suicidality class. Adolescents performing more walking workouts and having higher frequency of performing exercise during PE class belonged to the passive suicidality class; such individuals had suicidal thoughts but did not reach the stage of suicidal plan and attempt. Accordingly, it can be inferred that walking exercise and exercise during PE class can act as protective factors to prevent suicidal attempts. Such conclusion is consistent with those reported in previous studies, which stated that physical activities had a positive effect on psychological outcomes, such as depression, hopelessness, anxiety, and mental well-being [
30,
31]. Particularly, considering that exercise had the effect of reducing suicidal impulse [
32], walking exercise and active PE during PE class in school can help reduce suicide risk among adolescents. However, unlike previous studies reporting that physical activities had a positive effect on mental health [
30], our findings showed that there were no significant differences in high-intensity physical activities between all classes. In contrast, adolescents with higher frequency of moderate-intensity physical activities and level of muscle strengthening exercise were more likely to belong to the active or passive suicidality class than the non-suicidality class. Such findings should be interpreted with caution. Although the Youth Health Behavior Survey includes assessment of the intensity of physical activities, it does not include what type of physical activities were performed under what circumstances. There is a possibility that the findings in the present study may have been influenced by the inclusion of adolescents who were engaged in physical activities not as a leisure activity, but rather as part of part-time work or under the pressure of academic excellence, as well as young athletes and those exercising for weight loss, may have influenced the results [
33]. Exercise during PE class tended to be promoted when adolescents maintain a stable relationship with their peers, and, thus, it is believed to have produced results that are different from those of moderate-intensity physical activities. Based on these findings, it is necessary to gain deeper understanding of and identify factors that can negatively influence suicidality.
In the present study, adolescents with more violence victimization and sexual activity experiences were more likely to belong to active and passive suicidality classes. Violence victimization experience was found to be a predictor of suicidality in all classes. In particular, considering that studies have reported that violence victimization experience has a negative effect on the psychological state of the victim, including self-worth, hopelessness, and loneliness, which can lead to suicidal thought and behavior [
16], there is a need for intervention to treat psychological difficulties that students may face after violence victimization experience. Moreover, previous studies have identified that sexual activity, smoking, and drinking were associated with increased depression, suicidal thought, and suicidal attempt in adolescents, while another study reported that tests for suicidality should be seriously considered when treating adolescents who report sexual activity, drinking, and smoking [
18]. Considering these reports, screening for mental health issues of adolescents associated with such behaviors should help establish appropriate management plan for suicide prevention.
Furthermore, adolescents with health risk behaviors, such as smoking and drinking, were identified as having greater likelihood of belonging to suicidality group. Such findings have consistently appeared in previous studies [
34]. As adolescents’ smoke and drink by their own choice and action, such behaviors can be managed and modified. Accordingly, education and intervention to prevent adolescents from engaging in such risky behaviors are needed. Recently, the smoking and drinking rates among Korean adolescents have been reduced, but since the COVID-19 pandemic, the rates are being maintained or increasing slightly, which indicates the need for anti-smoking and anti-drinking education in schools. Considering a previous study that the demonstrated the effectiveness of media literacy education for preventing drinking during adolescence [
35], active use of school-based smoking and drinking media literacy education could help cessation of smoking and drinking, while continued education on cessation of smoking and drinking may have an effect on suicide prevention.
Academic grades were not a significant factor for differentiating between the suicide risk classes, especially between active and passive suicidality. However, it was a significant factor in the comparisons between non-suicidality and active suicidality and between non-suicidal and passive suicidality, with lower academic grades being associated with a higher suicidality. Academic grades of Korean adolescents can lead to academic stress, and, thus, that factor may be associated with suicidality. Therefore, although it cannot be claimed that all students with low academic grades have high suicidality, it is necessary to intervene to make sure that students with low academic grades do not exhibit academic stress and psychosocial problems.
Finally, middle school students, females, and students with lower household income were relatively more vulnerable to suicidality than their respective counterparts. Therefore, early intervention programs for middle school students should be designed for early screening and management of mental health issues among adolescents. Moreover, considering that female individuals and students with lower household income were relatively more vulnerable to suicidality, customized approach that considers sex-specific mental health differences and stress factors is also needed. In particular, availability of support systems with consideration for socioeconomic background should be checked and improvement of accessibility to mental health services should also be included.
Our findings emphasized the need for customized response strategies according to the level of suicidality when developing effective interventional strategies of suicide prevention for adolescents. The study focused on identifying vulnerable populations and identifying the characteristics of such populations. Influencing factors of suicide did not consist of a single factor, but rather, the influence was diverse and complex. Considering this point, accurately screening and selecting the target of intervention still remains a challenge. Therefore, the present study applied a holistic approach for identifying and measuring the factors that influence classification of suicidality classes from their daily life. Through this approach, we provided more specific and practical intervention measures that can be applied in clinical and educational settings. Our findings suggest that clinicians in clinical settings might find it beneficial to consider adolescents’ engagement in physical activities, such as walking and PE classes, as potential indicators to gauge suicide risk. This approach could help in identifying those who might be at higher risk, particularly if they are less active and have known risk factors. By incorporating this perspective into their assessment, clinicians may be able to tailor interventions in a more nuanced way, potentially improving early support for at-risk youth.
The present study had some limitations. First, cross-sectional data were used. Therefore, unlike data from panel surveys, continuous characteristics of individuals could not be identified and the causal relationship could not be accurately determined. Risky sexual activity, drinking, smoking, and low academic grades, which were assessed in the present study, could have led to interesting outcomes after the onset of a mental disorder. If long-term data can be analyzed, how suicidality of individuals changes and which factors influence such change can be analyzed longitudinally. Secondly, the Youth Health Behavior Survey is a self-reporting survey and the survey may include adolescents who provided insincere responses. To minimize this, the KDCA provided the data after data cleansing by imputing data with logical errors or outliers. Third, the definition of physical activity is unclear in the data provided by KYRBS. Depending on the type of physical activity and the individual’s attitude toward physical activity, the impact on emotions may be variable. Future research should confirm the impact of the type of physical activity and individual perception of physical activity on mental health. Additionally, research is needed on various daily activities that can affect the mental health of adolescents other than physical activity.
Despite these limitations, our study is important as it not only helped categorize the participants into groups of adolescents with and without having a suicidality but also categorized the suicidality groups into those with active and passive suicidality. Such differentiation enables preemptive intervention for adolescents who exhibit suicidality, while identification of major factors that influence the differentiation of suicidality classes enables classification of the suicidality of an individual according to his/her behavior. Moreover, considering that these factors are modifiable behaviors in daily life, adolescents who exhibit such risk can be screened more specifically in clinical and educational settings. Our findings emphasized the importance of multi-dimensional approach. Moreover, our study contributed to the literature as it highlighted the need for customized education focusing on the lifestyle habits of adolescents and provided the direction for future intervention.