Objectives: This study investigated changes in toothbrushing in adolescents in response to public health policy changes during coronavirus disease 2019 (COVID-19) focusing on behavioral trends before, during, and after policy enforcement according to socio-demographic subgroups. Methods: Data from the Korean Youth Risk Behavior Survey (2018–2024) were divided into 3 periods: before (2018–2019), during (2020–2022), and after (2023–2024) the implementation of COVID-19 school restrictions. A total of 354 943 middle and high school students were included. The primary outcome variable was self-reported toothbrushing after lunch at school. Multivariable logistic regression was conducted, adjusting for confounders such as sex, academic performance, school level, school type, handwashing, and oral health status (toothache and gum bleeding). Results: The compliance rate for toothbrushing declined significantly during the restriction period across all groups. It varied by sex, school type, school level, health-related behaviors (drinking, smoking, handwashing), and oral health status. Female students, middle schoolers, students in single-sex schools, non-smokers, and those practicing hand hygiene showed higher compliance. After restrictions were lifted, toothbrushing rates improved but remained lower than pre-pandemic levels. Recovery of the toothbrushing rate was observed in most groups, particularly among female students, high schoolers, and those with positive health-related behaviors. However, academic performance and oral health status were not significantly associated with recovery rate in adjusted analyses. Conclusions This study highlights that adolescents’ health behaviors are highly sensitive to environmental and policy changes. Variations in compliance and recovery rates underscore the need for adolescent-centered policies that account for both compliance and recovery, especially during crises such as pandemics.

Objective: Limited data exist on non-suicidal self-injury (NSSI) and suicide attempts among psychiatric patients in Korea. In this study,we investigated the clinical characteristics of patients who engaged in NSSI and/or suicide attempts. Methods: We performed a retrospective medical chart review of patients with NSSI and/or suicide attempts at the psychiatric departmentof a university medical center in Seoul between 2017 and 2019. According to their history, patients were allocated to one of threegroups: NSSI only, suicide attempts only and NSSI and suicide attempts group. Groups were compared based on sociodemographic characteristicsand psychological assessments. Results: Overall, 80 patients with NSSI and/or suicide attempts were evaluated. Patients with NSSI and suicide attempts were more likelyto be female than the other two groups. Patients with NSSI and suicide attempts were more likely to suffer from Cluster B personality disorderthan the other groups. And patients with NSSI and suicide attempts scored significantly higher on novelty-seeking in TCI and RC8,RC9 in MMPI-2. Conclusion Patients with NSSI and/or suicide attempts were more likely to be female, younger, and showed higher levels of psychologicaldisturbances. These findings highlight the importance of early detection and intervention for patients with NSSI.Psychiatry Investig 2020;17(4):320-330