An exploratory study on spatiotemporal clustering of suicide in Korean adolescents.

BACKGROUND: Adolescent suicides are more likely to form clusters than those of other age groups. However, the definition of a cluster in the space-time dimension has not been established, neither are the factors contributing to it well known. Therefore, this study aimed to identify space-time clusters in adolescent suicides in Korea and to examine the differences between clustered and non-clustered cases using novel statistical methods. METHODS: From 2016 to 2020, the dates and locations, including specific addresses from which the latitude and longitude of all student suicides (aged 9-18 years) in Korea were obtained through student suicide reports. Sociodemographic characteristics of the adolescents who died by suicide were collected, and the individual characteristics of each student who died by suicide were reported by teachers using the Strengths and Difficulties Questionnaire (SDQ). Density-Based Spatial Clustering of Applications with Noise (DBSCAN) analysis was used to assess the clustering of suicides. RESULTS: We identified 23 clusters through the data analysis of 652 adolescent suicides using DBSCAN. By comparing the size of each cluster, we identified 63 (9.7%) spatiotemporally clustered suicides among adolescents, and the temporal range of these clusters was 7-59 days. The suicide cluster group had a lower economic status than the non-clustered group. There were no significant differences in other characteristics between the two groups. CONCLUSION: This study has defined the space-time cluster of suicides using a novel statistical method. Our findings suggest that when an adolescent suicide occurs, close monitoring and intervention for approximately 2 months are needed to prevent subsequent suicides. Future research using DBSCAN needs to involve a larger sample of adolescents from various countries to further corroborate these findings.

A Comparative Study of Suicide Rates among 10-19-Year-Olds in 29 OECD Countries.

OBJECTIVE: This study had two main objectives: to compare current suicide rates in OECD countries among 10-19-year-olds and to identify patterns of suicide rates based on age, gender and time. Furthermore we investigated the main dimensions that contributed to the variation in child and adolescent suicide rates across countries. METHODS: We combined the WHO mortality data and the population data released by OECD to calculate the suicide rates in 29 OECD countries. A self-organizing map (SOM), k-means clustering analysis, and multi-dimensional scaling were used to classify countries based on similarities in suicide rate structure and to identify the important dimensions accounting for differences among groups. RESULTS: We identified significant differences in suicide rates depending on age, sex, country, and time period. Late adolescence and male gender were universal risk factors for suicide, and we observed a general trend of declining suicide rates in OECD countries. The SOM analysis yielded eight types of countries. Most countries showed gender gaps in suicide rates of similar magnitudes; however, there were outliers in which the gender gap was particularly large or small. CONCLUSION: Significant variation exists with respect to suicide rates and their associated gender gaps in OECD countries.

Disparities in mortality by disability: an 11-year follow-up study of 1 million individuals.

OBJECTIVES: This longitudinal study examines to what extent the risk of mortality-all-cause, natural death, suicide, and unintentional injury mortality-differs by types and severity of disabilities as well as disability status. METHODS: Data were the National Sample Cohort of 1,025,340 individuals in South Korea followed from 2002 to 2013. Cox regression with time-variant variables was used to estimate the hazard ratio of mortality by disability. RESULTS: Individuals with disabilities had a higher risk of mortality compared to those without (HR 1.84, 95% CI 1.80-1.88 for natural death; HR 1.83, 95% CI 1.64-2.03 for suicide; HR 1.54, 95% CI 1.38-1.71 for unintentional injury). All types of disability were associated with an increased risk of natural death. Individuals with mental disability were the highest risk group for suicide (HR 7.14, 95% CI 5.31-9.60). People defined as having severe disability had an elevated risk for all categories of mortality. CONCLUSIONS: Disabilities are important markers of high risk of mortality. Findings call for actions to reduce mortality risk of people with disabilities, including preventing suicidal behaviors of those with mental disability.

The Structure of Co-Occurring Bullying Experiences and Associations with Suicidal Behaviors in Korean Adolescents.

OBJECTIVE: This study had two main goals: to examine the structure of co-occurring peer bullying experiences among adolescents in South Korea from the perspective of victims and to determine the effects of bullying on suicidal behavior, including suicidal ideation and suicide attempts, among adolescents. METHOD: This study used data gathered from 4,410 treatment-seeking adolescents at their initial visits to 31 local mental health centers in Gyeonggi Province, South Korea. The structure of peer bullying was examined using latent class analysis (LCA) to classify participants' relevant experiences. Then, a binomial logistic regression adjusted by propensity scores was conducted to identify relationships between experiences of being bullied and suicidal behaviors. RESULTS: The LCA of experiences with bullying revealed two distinct classes of bullying: physical and non-physical. Adolescents who experienced physical bullying were 3.05 times more likely to attempt suicide than those who were not bullied. Victims of (non-physical) cyber bullying were 2.94 times more likely to attempt suicide than were those who were not bullied. CONCLUSIONS: Both physical and non-physical bullying were associated with suicide attempts, with similar effect sizes. Schools and mental health professionals should be more attentive than they currently are to non-physical bullying.