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.

The purpose of the current study was to examine the risk factors of young children’s smartphone addiction in a longitudinal study design. Data collected from 313 participants (mean age, 4.5 ± 0.82 years; male, 49.8%) over 4 years for Kids Cohort for Understanding of Internet Addiction Risk Factors in Early Childhood were analyzed in this study. Mixed effect models were used to evaluate the influence of various variables on the repeated measures of smartphone addiction tendency in young children over time. The multi-level analysis showed that parents’ lack of control over children’s smartphone use (t = −4.523; 95% confidence interval [CI], −7.32, −1.72), and parents’ higher smartphone addiction proneness (t = 6.340;95% CI, 0.23, 0.440) predicted higher smartphone addiction tendency in young children.The responsibility of the parents to prevent their children from becoming addicted to smartphones should start in a very early age when they start using the smartphones.

The purpose of the current study was to examine the risk factors of young children’s smartphone addiction in a longitudinal study design. Data collected from 313 participants (mean age, 4.5 ± 0.82 years; male, 49.8%) over 4 years for Kids Cohort for Understanding of Internet Addiction Risk Factors in Early Childhood were analyzed in this study. Mixed effect models were used to evaluate the influence of various variables on the repeated measures of smartphone addiction tendency in young children over time. The multi-level analysis showed that parents’ lack of control over children’s smartphone use (t = −4.523; 95% confidence interval [CI], −7.32, −1.72), and parents’ higher smartphone addiction proneness (t = 6.340;95% CI, 0.23, 0.440) predicted higher smartphone addiction tendency in young children.The responsibility of the parents to prevent their children from becoming addicted to smartphones should start in a very early age when they start using the smartphones.

The purpose of the current study was to examine the risk factors of young children’s smartphone addiction in a longitudinal study design. Data collected from 313 participants (mean age, 4.5 ± 0.82 years; male, 49.8%) over 4 years for Kids Cohort for Understanding of Internet Addiction Risk Factors in Early Childhood were analyzed in this study. Mixed effect models were used to evaluate the influence of various variables on the repeated measures of smartphone addiction tendency in young children over time. The multi-level analysis showed that parents’ lack of control over children’s smartphone use (t = −4.523; 95% confidence interval [CI], −7.32, −1.72), and parents’ higher smartphone addiction proneness (t = 6.340;95% CI, 0.23, 0.440) predicted higher smartphone addiction tendency in young children.The responsibility of the parents to prevent their children from becoming addicted to smartphones should start in a very early age when they start using the smartphones.

The purpose of the current study was to examine the risk factors of young children’s smartphone addiction in a longitudinal study design. Data collected from 313 participants (mean age, 4.5 ± 0.82 years; male, 49.8%) over 4 years for Kids Cohort for Understanding of Internet Addiction Risk Factors in Early Childhood were analyzed in this study. Mixed effect models were used to evaluate the influence of various variables on the repeated measures of smartphone addiction tendency in young children over time. The multi-level analysis showed that parents’ lack of control over children’s smartphone use (t = −4.523; 95% confidence interval [CI], −7.32, −1.72), and parents’ higher smartphone addiction proneness (t = 6.340;95% CI, 0.23, 0.440) predicted higher smartphone addiction tendency in young children.The responsibility of the parents to prevent their children from becoming addicted to smartphones should start in a very early age when they start using the smartphones.

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.