Objectives: Currently, more than 80% of Korean police officers are assigned to a 24-hour rotating shift system. Shift workers’ sleep patterns change frequently, which may result in circadian rhythm desynchrony and sleep disturbance. The goal of this study was to compare sleep and cognitive functioning in different shift types. In addition, we analyzed the difference in cognitive functioning depending on whether shift workers took a night nap prior to their night shift. Methods: A total of 278 police officers working in Seoul (mean age 45.27±9.00 years, 88.5% male) participated, providing demographic information and completing selfreport questionnaires [Insomnia Severity Index, Epworth Sleepiness Scale, Munich ChronoType Questionnaire (Shift-work type), Patient Health Questionnaire-9]. Participants also performed the Psychomotor Vigilance Task, Trail Making Test A & B, and Stroop Test. Results: Participants included 57 (20.5%) day workers and 221 (79.5%) shift workers. The average Insomnia Severity Index score of shift workers was significantly higher than day workers (t=-2.861, p=0.005). Shift workers also slept about 0.78 hours less than day workers (t=4.730, p<0.001). Among shift workers, 66.3% (n=128) reported they took night naps prior to their night shift, sleeping on average 1.78 hours. Shift workers who took night naps had faster reaction times on the Trail Making Test A task [F(1, 136)=5.741, p=0.018], and significantly fewer Stroop C errors [F(1, 137)=5.638, p=0.019] than those who did not. Conclusions Shift working police officers reported significantly worse insomnia symptoms and slept less compared to their non-shift-working counterparts. Taking a night nap improved focused and selective attention.

Objectives: Currently, more than 80% of Korean police officers are assigned to a 24-hour rotating shift system. Shift workers’ sleep patterns change frequently, which may result in circadian rhythm desynchrony and sleep disturbance. The goal of this study was to compare sleep and cognitive functioning in different shift types. In addition, we analyzed the difference in cognitive functioning depending on whether shift workers took a night nap prior to their night shift. Methods: A total of 278 police officers working in Seoul (mean age 45.27±9.00 years, 88.5% male) participated, providing demographic information and completing selfreport questionnaires [Insomnia Severity Index, Epworth Sleepiness Scale, Munich ChronoType Questionnaire (Shift-work type), Patient Health Questionnaire-9]. Participants also performed the Psychomotor Vigilance Task, Trail Making Test A & B, and Stroop Test. Results: Participants included 57 (20.5%) day workers and 221 (79.5%) shift workers. The average Insomnia Severity Index score of shift workers was significantly higher than day workers (t=-2.861, p=0.005). Shift workers also slept about 0.78 hours less than day workers (t=4.730, p<0.001). Among shift workers, 66.3% (n=128) reported they took night naps prior to their night shift, sleeping on average 1.78 hours. Shift workers who took night naps had faster reaction times on the Trail Making Test A task [F(1, 136)=5.741, p=0.018], and significantly fewer Stroop C errors [F(1, 137)=5.638, p=0.019] than those who did not. Conclusions Shift working police officers reported significantly worse insomnia symptoms and slept less compared to their non-shift-working counterparts. Taking a night nap improved focused and selective attention.

Suicide is a complex phenomenon resulting from interactions between individual vulnerabilities and socio-environmental factors. The current review primarily focuses on research into the serotonin system, hypothalamic-pituitary-adrenal axis, neurotrophic factors, lipid metabolism, and functional neuroimaging studies. It has been found that dysfunctions in the serotonin system, hypothalamic-pituitary-adrenal axis abnormalities, and low brain-derived neurotrophic factor and cholesterol levels may be linked to suicide. Additionally, recent neuroimaging studies have suggested that structural and functional abnormalities in brain areas related to cognitive and emotional regulation may be associated with suicide. More research incorporating advanced methodological approaches may shed further light on the neurobiological basis of suicide.
Brain ; Brain-Derived Neurotrophic Factor ; Cholesterol ; Functional Neuroimaging ; Lipid Metabolism ; Nerve Growth Factors ; Neurobiology ; Neuroimaging ; Pituitary-Adrenal System ; Serotonin ; Suicide

Suicide is a complex phenomenon resulting from interactions between individual vulnerabilities and socio-environmental factors. The current review primarily focuses on research into the serotonin system, hypothalamic-pituitary-adrenal axis, neurotrophic factors, lipid metabolism, and functional neuroimaging studies. It has been found that dysfunctions in the serotonin system, hypothalamic-pituitary-adrenal axis abnormalities, and low brain-derived neurotrophic factor and cholesterol levels may be linked to suicide. Additionally, recent neuroimaging studies have suggested that structural and functional abnormalities in brain areas related to cognitive and emotional regulation may be associated with suicide. More research incorporating advanced methodological approaches may shed further light on the neurobiological basis of suicide.

Objective: The purpose of the present study was to develop and validate the Korean version of the clinician-administered KSADSCOMP, which is the recently updated, web-based computerized version of the Kiddie Schedule for Affective Disorders and Schizophrenia for school-age children (KSADS). Methods: A total of 71 participants (mean age=12.04±3.86 years, female=29.57%) participated in the study. A child-adolescent psychiatrist established a diagnosis for the participant after a thorough psychiatric interview with the participant and the parent. Researchers who were blind to the diagnoses administered the clinician-administered KSADS-COMP to the parents and participants. The gold-standard diagnoses made by child-adolescent psychiatrists were compared to the current diagnoses generated by the clinician-administered KSADS-COMP. Percent agreement, Cohen’s Kappa, Gwet’s first-order agreement coefficient (AC1), sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Results: Gwet’s AC1, our preferred measure of agreement, showed excellent range between 0.78 and 1. Sensitivity, specificity, positive predicted value and negative predictive value also showed high scores. Conclusion The current study demonstrated excellent criterion validity of the Korean version of the clinician-administered KSADSCOMP, though the small sample size could be a limitation. The current study was the first study to examine the criterion validity of the KSADS-COMP. Due to its readily usable format and efficient and accurate diagnostic process, widely-use of KSADS-COMP is expected.

Objectives: This study identified the association between excessive exposure to screen media and behavioral and emotional problems in elementary school students. Methods: A total of 331 parents of children aged 7–10 years were recruited from “The Kids Cohort for Understanding of Internet Addiction Risk Factors in Early Childhood (K-CURE)” study. Children’s demographics, household media ownership, screen time, and behavioral/emotional problems were assessed using a parental questionnaire. Children’s behavior/emotional problems were measured using the Korean version the of Child Behavior Checklist (K-CBCL) score. Results: The total K-CBCL score in the screen overuse group was 51.18±9.55, significantly higher than 47.28±10.09 in the control group (t=2.14, p=0.05). For each subscale, the externalization score (51.65±10.14, 48.33±8.97, respectively; t=2.02, p<0.05), social problem score (55.41±6.11, 53.24±5.19, respectively; t=2.27, p<0.05), and rule breaking behavior score (55.71±6.11, 53.24±5.19, respectively; t=2.27, p<0.05) were significantly higher in the screen overuse group than in the control group. In addition, the screen overuse group also had a significantly higher usage rate than the control group, even if limited to smartphones, not only on weekdays (3.56±2.08, 1.87±2.02, respectively; t=-4.597, p<0.001) but also weekends (1.62±0.74, 1.19±0.83, respectively; t=-3.14, p=0.003). Conclusion The study suggested that screen media overuse patterns in children in Korea are particularly relevant to the excessive use of smartphones and are related to higher risks of emotional and behavioral problems.

Objectives: This study identified the association between excessive exposure to screen media and behavioral and emotional problems in elementary school students. Methods: A total of 331 parents of children aged 7–10 years were recruited from “The Kids Cohort for Understanding of Internet Addiction Risk Factors in Early Childhood (K-CURE)” study. Children’s demographics, household media ownership, screen time, and behavioral/emotional problems were assessed using a parental questionnaire. Children’s behavior/emotional problems were measured using the Korean version the of Child Behavior Checklist (K-CBCL) score. Results: The total K-CBCL score in the screen overuse group was 51.18±9.55, significantly higher than 47.28±10.09 in the control group (t=2.14, p=0.05). For each subscale, the externalization score (51.65±10.14, 48.33±8.97, respectively; t=2.02, p<0.05), social problem score (55.41±6.11, 53.24±5.19, respectively; t=2.27, p<0.05), and rule breaking behavior score (55.71±6.11, 53.24±5.19, respectively; t=2.27, p<0.05) were significantly higher in the screen overuse group than in the control group. In addition, the screen overuse group also had a significantly higher usage rate than the control group, even if limited to smartphones, not only on weekdays (3.56±2.08, 1.87±2.02, respectively; t=-4.597, p<0.001) but also weekends (1.62±0.74, 1.19±0.83, respectively; t=-3.14, p=0.003). Conclusion The study suggested that screen media overuse patterns in children in Korea are particularly relevant to the excessive use of smartphones and are related to higher risks of emotional and behavioral problems.

Background: Coronavirus disease 2019 (COVID-19) is different from previous disasters in that it continues to the present and has affected all aspects of family life. During epidemics, psychosocial support is not less important than infection control. During COVID-19-related school closures, prolonged partial closures of schools could have detrimental social and health consequences for children and may increase the burden on the family. Based on a community sample in Korea, this study identified parental concerns, children's media usage, other various factors and examined whether parental stress level or depression were positively associated with problem behaviors, media exposure, and sleep problems of the primary school children during school closure under COVID-19. Methods: Participants were 217 parents residing in Suwon, South Korea, who had primary school children and responded to a web-based questionnaire on parental concerns from school closure under COVID-19, subjective stress, depression, whether having received mental health services, and family characteristics; children's sleep patterns, problem behaviors, media usage during the online-only class period, and changes in activity level following the pandemic. Results: During school closure, children gained body weight, spent less time in physical activities and more in media usage. Besides online learning content (97.2%), YouTube was highly used content (87.6%), and games followed (78.3%). Parental subjective stress index was highly associated with parental depression (Pearson correlation 0.439, P < 0.001), children's sleep problems (0.283, P < 0.001), tablet time (0.171, P = 0.012) and behavior problems (0.413, P < 0.001). Parental depression was associated with children's sleep problems (0.355, P < 0.001), TV time (0.153, P = 0.024), tablet time (0.159, P = 0.019), and behavior problems (0.524, P < 0.001). Parents who previously received mental services seemed to be more concerned about the problems their children already have getting worse because of COVID-19 than the disease itself. Children's sleep problem was associated with tablet (0.172, P = 0.011) and smartphone time (0.298, P < 0.001), but not its frequency. Conclusion During COVID-19-related school closures, many parents and children had various difficulties relating to mental health. Ongoing monitoring of mental health of highrisk groups and multiple support systems may need to be expanded to cover those parents having difficulty in caring for their children.

Background: Coronavirus disease 2019 (COVID-19) is different from previous disasters in that it continues to the present and has affected all aspects of family life. During epidemics, psychosocial support is not less important than infection control. During COVID-19-related school closures, prolonged partial closures of schools could have detrimental social and health consequences for children and may increase the burden on the family. Based on a community sample in Korea, this study identified parental concerns, children's media usage, other various factors and examined whether parental stress level or depression were positively associated with problem behaviors, media exposure, and sleep problems of the primary school children during school closure under COVID-19. Methods: Participants were 217 parents residing in Suwon, South Korea, who had primary school children and responded to a web-based questionnaire on parental concerns from school closure under COVID-19, subjective stress, depression, whether having received mental health services, and family characteristics; children's sleep patterns, problem behaviors, media usage during the online-only class period, and changes in activity level following the pandemic. Results: During school closure, children gained body weight, spent less time in physical activities and more in media usage. Besides online learning content (97.2%), YouTube was highly used content (87.6%), and games followed (78.3%). Parental subjective stress index was highly associated with parental depression (Pearson correlation 0.439, P < 0.001), children's sleep problems (0.283, P < 0.001), tablet time (0.171, P = 0.012) and behavior problems (0.413, P < 0.001). Parental depression was associated with children's sleep problems (0.355, P < 0.001), TV time (0.153, P = 0.024), tablet time (0.159, P = 0.019), and behavior problems (0.524, P < 0.001). Parents who previously received mental services seemed to be more concerned about the problems their children already have getting worse because of COVID-19 than the disease itself. Children's sleep problem was associated with tablet (0.172, P = 0.011) and smartphone time (0.298, P < 0.001), but not its frequency. Conclusion During COVID-19-related school closures, many parents and children had various difficulties relating to mental health. Ongoing monitoring of mental health of highrisk groups and multiple support systems may need to be expanded to cover those parents having difficulty in caring for their children.

Background: As the coronavirus disease 2019 (COVID-19) has continued for a couple of years, the long-term effects of the pandemic and the subsequent school curriculum modification on the mental health of children and parents need to be investigated. To clarify the changes that can occur during one school year and to predict the risk factors for vulnerable groups, this study identified parameters relative to children’s screen time, their problematic behavior, and parental depression. Methods: A total of 186 participants were analyzed who were parents of elementary schoolchildren in South Korea. These parents were required to complete a web-based questionnaire twice. The questionnaires were conducted in June 2020 and September 2021. Participants’ general demographics including family income, children’s screen time, sleep patterns, problematic behavior, and parental depression were assessed via the parental questionnaire that included various measurement tools. Results: Children’s body mass index (BMI) increased significantly in 2021 (18.94 ± 3.75 vs. 18.14 ± 3.30, P < 0.001). Smartphone frequency of use per week (5.35 vs. 4.54, P < 0.001) and screen time per day (3.52 vs. 3.16, P < 0.001) significantly increased during the period of the COVID-19 pandemic. The television screen time (2.88 vs. 3.26, P < 0.001), frequency of viewing (3.77 vs. 4.77, P < 0.001), and children’s problematic behaviors significantly decreased (9.15 vs. 11.85,P < 0.001). A lower income household was a key predictor of increased smartphone frequency (B = 1.840, 95% confidence interval [CI], 0.923–2.757, P < 0.001) and smartphone screen time (B = 1.992, 95% CI, 1.458–2.525, P < 0.001). The results showed that the lower income household (B = 5.624, 95% CI, 2.927–8.320, P < 0.001) and a child’s psychiatric treatment history (B = 7.579, 95% CI, 5.666–9.492, P < 0.001) was the most significant predictor of problematic behaviors of children and parental depression (B = 3.476, 95% CI, 1.628–5.325, P < 0.001; B = 3.138, 95% CI, 1.827–4.450, P < 0.001). Conclusion This study suggested that children’s smartphone screen time and BMI increased during COVID-19 because of the school curriculum modification following school closures in South Korea. The increased children’s problematic behaviors and parental depression were predicted by lower-income households and the previous psychiatric history of children. These results indicate that multiple social support systems to the vulnerable group are needed during the ongoing pandemic and that a modified school setting is required.