Sleep habits and problems across gestational progress in Japanese women.

BACKGROUND: Pregnancy-related anatomic, physiologic, and hormonal factors can occur at different stages of pregnancy and affect sleep disturbances. Sleep problems and habits among Japanese women across gestational stages have not been described. This study aimed to elucidate sleep problems, including a high risk of sleep-disordered breathing and sleep habits, among Japanese women across gestational progress, including postpartum. METHODS: A questionnaire survey using the Pittsburgh Sleep Quality Index (PSQI) and Berlin Questionnaire was conducted for 683 pregnant women (223 in the second trimester, 453 in the third trimester) and 386 postpartum (within 1 week after delivery). RESULTS: The total PSQI score was 5.3 [2.6] in the second trimester, 6.1 [2.8] in the third trimester, and 6.8 [3.1] in the first week postpartum. The percentage of those at high risk for sleep-disordered breathing, as determined by the Berlin Questionnaire, was 11.8% in the second trimester, 21.3% in the third trimester, and 19.2% in the first week postpartum, with the highest percentage of those at high risk in the third trimester of pregnancy. CONCLUSION: The PSQI total score exceeded the cut-off value in the third trimester and the first week postpartum, suggesting sleep deterioration. Therefore, it is necessary to understand and support sleep in pregnant women to ensure safe delivery, postpartum recovery, and health.

Outdoor daylight exposure and longer sleep promote wellbeing under COVID-19 mandated restrictions.

Light is an important regulator of daily human physiology in providing time-of-day information for the circadian clock to stay synchronised with the 24-hr day. The coronavirus disease 2019 (COVID-19) pandemic led to social restrictions in many countries to prevent virus spreading, restrictions that dramatically altered daily routines and limited outdoor daylight exposure. We previously reported that sleep duration increased, social jetlag decreased, and mid-sleep times delayed during social restrictions (Global Chrono Corona Survey, N = 7,517). In the present study, we investigated in the same dataset changes in wellbeing and their link to outdoor daylight exposure, and sleep-wake behaviour. In social restrictions, median values of sleep quality, quality of life, physical activity and productivity deteriorated, while screen time increased, and outdoor daylight exposure was reduced by ~58%. Yet, many survey participants also reported no changes or even improvements. Larger reductions in outdoor daylight exposure were linked to deteriorations in wellbeing and delayed mid-sleep times. Notably, sleep duration was not associated with outdoor daylight exposure loss. Longer sleep and decreased alarm-clock use dose-dependently correlated with changes in sleep quality and quality of life. Regression analysis for each wellbeing aspect showed that a model with six predictors including both levels and their deltas of outdoor daylight exposure, sleep duration and mid-sleep timing explained 5%-10% of the variance in changes of wellbeing scores (except for productivity). As exposure to daylight may extenuate the negative effects of social restriction and prevent sleep disruption, public strategies during pandemics should actively foster spending more daytime outdoors.

Association of sleep duration on workdays or free days and social jetlag with job stress.

AIM: The aim of this study was to investigate the impact of sleep problems on job stress in office workers. METHODS: This study included 4645 office workers from 29 companies who completed the study questionnaires between April 2017 and April 2019 in Japan. Sleep duration was assessed based on the participants' subjective sleep schedule on workdays and free days. The midpoint of sleep on free days (sleep-corrected) and social jetlag were calculated in accordance with the Munich Chronotype Questionnaire. To assess job stress, we used the 57-item Brief Job Stress Questionnaire. RESULTS: Multivariate logistic regression analysis revealed that the following factors were significantly associated with high job stress in office workers: a sleep duration <6 h on workdays (OR = 1.77, 95% CI = 1.46-2.15, P < 0.001), a sleep duration <6 h on free days (OR = 1.40, 95% CI = 1.05-1.87, P = 0.022), a sleep duration of at least 8 h on free days (OR = 1.31, 95% CI = 1.06-1.60, P = 0.011), and more than 2 h of social jetlag (OR = 1.33, 95% CI = 1.04-1.70, P = 0.022). CONCLUSION: This study suggests that insufficient sleep, long sleep durations on free days, and social jetlag may be associated with high job stress in office workers.

Internet-based survey of factors associated with subjective feeling of insomnia, depression, and low health-related quality of life among Japanese adults with sleep difficulty.

BACKGROUND: This study was conducted to determine what symptom components or conditions of insomnia are related to subjective feelings of insomnia, low health-related quality of life (HRQOL), or depression. METHOD: Data from 7,027 Japanese adults obtained using an Internet-based questionnaire survey was analyzed to examine associations between demographic variables and each sleep difficulty symptom item on the Pittsburgh Sleep Quality Index (PSQI) with the presence/absence of subjective insomnia and scores on the Short Form-8 (SF-8) and Center for Epidemiologic Studies Depression Scale (CES-D). RESULTS: Prevalence of subjective insomnia was 12.2% (n = 860). Discriminant function analysis revealed that item scores for sleep quality, sleep latency, and sleep medication use on the PSQI and CES-D showed relatively high discriminant function coefficients for identifying positivity for the subjective feeling of insomnia. Among respondents with subjective insomnia, a low SF-8 physical component summary score was associated with higher age, depressive state, and PSQI items for sleep difficulty and daytime dysfunction, whereas a low SF-8 mental component summary score was associated with depressive state, PSQI sleep latency, sleeping medication use, and daytime dysfunction. Depressive state was significantly associated with sleep latency, sleeping medication use, and daytime dysfunction. CONCLUSION: Among insomnia symptom components, disturbed sleep quality and sleep onset insomnia may be specifically associated with subjective feelings of the disorder. The existence of a depressive state could be significantly associated with not only subjective insomnia but also mental and physical QOL. Our results also suggest that different components of sleep difficulty, as measured by the PSQI, might be associated with mental and physical QOL and depressive status.

Factors associated with duration before receiving definitive diagnosis of narcolepsy among Japanese patients affected with the disorder.

BACKGROUND: Narcolepsy (NA) is a sleep disorder characterized by excessive daytime sleepiness and an increased propensity of rapid eye movement sleep. If left untreated, NA can lead to academic underachievement or job loss because of dozing off or mistakes caused by inattentiveness due to sleepiness. PURPOSE: Although untreated narcolepsy patients may suffer from many social disadvantages due to excessive daytime sleepiness, mostly it takes a long time to receive a definitive diagnosis of the disorder. This retrospective study investigated factors related to the period until definitive diagnosis among patients with narcolepsy in Japan. METHODS: We enrolled 181 consecutive patients (108 men, 73 women; mean age 37.6 ± 16.6 years old; narcolepsy with cataplexy/narcolepsy without cataplexy = 131:50). Multivariate logistic regression analysis was performed with period until definitive diagnosis as the dependent variable and descriptive clinical variables as the independent variables. RESULTS: The mean period until receiving the diagnosis among the participants was 9.9 ± 10.1 years. More than half of the patients first learned about the disorder from information provided by the media. Multivariate logistic analysis indicated that adult onset (p < 0.01), onset in 1995 or later (p < 0.001), and first learning about the disorder from a sleep disorder specialist physician or a general practitioner (p < 0.001) were associated with a time taken for receiving a definitive diagnosis less than or equal to the median value (7 years). CONCLUSION: Improving access to information about the concept of the disorder and the medical institutions specialized in sleep disorders, especially via the Internet, would be necessary to promote early diagnosis of the disorder.

Sleep patterns in Metropolitan and Regional areas in Japan: Before and during COVID-19 social restrictions.

Sleep timing is an important output of the circadian system. The COVID-19-mandated social restrictions significantly altered commuting time and sleep duration regionally in Japan. This study aimed to elucidate sleep patterns, especially chronotype and social jetlag (SJL), due to changes in social time pressure through the social restrictions between the Metropolitan and Regional areas in Japan. As part of the Global Chrono Corona Survey 2020 (GCCS), the data were collected during social restrictions (SR), but pre-COVID-19 behaviours were also queried retrospectively. We analyzed a cohort of 729 respondents representing both the Metropolitan and the Regional areas separately for workdays and work-free days. While the areas showed no difference in SJL before SR, the differential decrease was larger in the Metropolitan area during SR, resulting in a significant difference in SJL between the areas. The outdoor light exposure before SR was 30 min longer in the Metropolitan areas than in the Regional; during SR both areas showed similarly low (below 1 h) outdoor light exposures. The variables associated with decreased SJL were the Metropolitan areas, work-from-home, a no-usage alarm clock on workdays, and chronotypes (mid-sleep time on free days corrected for sleep deficit accumulated over the workweek, MSFsc) during SR. The results suggest that relaxed social schedules, as reflected in the increased frequency of work-from-home and reduced alarm clock use, and moving towards earlier MSFsc during SR were linked to decreased SJL and were more prominent in the Metropolitan areas. This study provides insights into sleep patterns and the social time pressure markers, by comparison between residential groups in Japan.

A psychometric analysis of the Japanese version of the clinically useful depression outcome scale supplemented with questions for the DSM-5 anxious distress specifier (CUDOS-A).

AIM: The aim of the study was to identify the clinical significance of anxiety in those with depression, the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5) defined criteria for an anxious distress specifier for major depressive disorder (MDD). The Clinically Useful Depression Outcome Scale (CUDOS) supplemented with questions for the DSM-5 anxious distress specifier (CUDOS-A) is a self-report instrument to assess the clinical significance of anxiety in addition to assess symptoms and the severity of depression. This study aimed to evaluate the psychometric properties of the Japanese version of the CUDOS-A. METHODS: An observational, prospective study was conducted with 131 MDD outpatients and 200 healthy controls. The Japanese version of the CUDOS-A, along with other measures, was administered to assess depressive symptoms, anxiety, social function, and biological rhythm. Reliability and validity analyses were performed, including internal consistency, test-retest reliability, convergent validity, and contrasted-groups validity. RESULTS: The Japanese version of the CUDOS-A demonstrated excellent internal consistency (Cronbach's alpha = 0.96) and test-retest reliability (ICC = 0.78). Significant positive correlations were found between the CUDOS-A and measures of depression, anxiety, social function, and biological rhythm (all, p < 0.001), supporting its convergent validity. The CUDOS-A effectively differentiated between patients with MDD and healthy controls (p < 0.001), indicating good contrasted-groups validity. CONCLUSIONS: The Japanese version of the CUDOS-A is a useful measure for research and for clinical practice, enabling the efficient assessment of anxious distress in individuals with depression.

Delayed sleep-wake phase disorder and its related sleep behaviors in the young generation.

Delayed sleep-wake phase disorder (DSWPD) is a sleep disorder in which the habitual sleep-wake timing is delayed, resulting in difficulty in falling asleep and waking up at the desired time. Patients with DSWPD frequently experience fatigue, impaired concentration, sleep deprivation during weekdays, and problems of absenteeism, which may be further complicated by depressive symptoms. DSWPD is typically prevalent during adolescence and young adulthood. Although there are no studies comparing internationally, the prevalence of DSWPD is estimated to be approximately 3% with little racial differences between Caucasians and Asians. The presence of this disorder is associated with various physiological, genetic and psychological as well as behavioral factors. Furthermore, social factors are also involved in the mechanism of DSWPD. Recently, delayed sleep phase and prolonged sleep duration in the young generation have been reported during the period of COVID-19 pandemic-related behavioral restrictions. This phenomenon raises a concern about the risk of a mismatch between their sleep-wake phase and social life that may lead to the development of DSWPD after the removal of these restrictions. Although the typical feature of DSWPD is a delay in circadian rhythms, individuals with DSWPD without having misalignment of objectively measured circadian rhythm markers account for approximately 40% of the cases, wherein the psychological and behavioral characteristics of young people, such as truancy and academic or social troubles, are largely involved in the mechanism of this disorder. Recent studies have shown that DSWPD is frequently comorbid with psychiatric disorders, particularly mood and neurodevelopmental disorders, both of which have a bidirectional association with the pathophysiology of DSWPD. Additionally, patients with DSWPD have a strong tendency toward neuroticism and anxiety, which may result in the aggravation of insomnia symptoms. Therefore, future studies should address the effectiveness of cognitive-behavioral approaches in addition to chronobiological approaches in the treatment of DSWPD.

Social jetlag among Japanese adolescents: Association with irritable mood, daytime sleepiness, fatigue, and poor academic performance.

Social jetlag, a form of circadian misalignment, has been suggested to induce several clinical symptoms such as mental/physical health problems. However, evidence on the association of social jetlag with general daytime functioning (e.g., school life) is limited. This cross-sectional study aimed to 1) estimate the distribution of social jetlag exceeding one hour and 2) comprehensively explore the associations between social jetlag and irritable mood, daytime sleepiness, and poor academic performance among Japanese adolescents. The study included 4,782 students aged 12-15 years, from 13 junior high schools, who completed a self-administered questionnaire. Social jetlag was calculated as the difference in the midpoint of sleep between weekdays and weekends and was categorized as follow: negative, <1 h, 1-2 h, or ≥2 h. Outcomes were irritable mood, daytime sleepiness, and academic performance, which were analyzed with generalized linear mixed models to examine the relations with social jetlag, with adjustments for potential confounders like sleep quality. The distribution of social jetlag of ≥1 h was 51.1%, including 1-2 h (35.8%) and ≥2 h (15.3%). Its most frequently observed duration was 0 to <1 h (41.0%), followed by negative social jetlag (7.9%). The full adjusted model revealed that social jetlag of ≥1 h was associated with elevated risk of irritable mood, daytime sleepiness, and poor academic performance, while negative social jetlag was associated only with poor academic performance. Social jetlag was highly prevalent among Japanese adolescents and could be a major risk factor for irritable mood, daytime sleepiness, and poor academic performance.Abbreviations: BMI, Body mass index; DLMO, Dim light melatonin onset; CIs, Confidence intervals; MSF, The midpoints of sleep on free days; MSFsc, Sleep-corrected MSF; MSW, The midpoints of sleep on weekdays; PDSS, The Pediatric Daytime Sleepiness Scale.

Prevalence and Factors Associated With the Risk of Delayed Sleep-Wake Phase Disorder in Japanese Youth.

Background: Delayed sleep-wake phase disorder (DSWPD) is more prevalent among the younger generation. However, the prevalence of this disorder in Asia, particularly Japan, has not yet been elucidated. Furthermore, the impact of DSWPD morbidity on daytime functioning and factors associated with the presence of the disorder remain unclear. Methods: A web-based survey was conducted among youth aged 15-30 years. In total, 7,810 individuals completed the questionnaire. The questionnaire included items on sociodemographic variables as well as the Japanese version of the Biological Rhythms Interview of Assessment in Neuropsychiatry self-report (J-BRIAN-SR), which assesses the risk of DSWPD, sleep behaviors and possibly related lifestyle variables, productivity loss [WHO Health and Work Performance Questionnaire (HPQ)], and health-related quality of life (HRQOL). The risk of DSWPD was indicated by a J-BRIAN-SR score greater than or equal to 40 points and days of absence ≥4 days per month. After comparing these variables for participants at risk of DSWPD and those who were not, the factors associated with the risk of DSWPD were examined using logistic regression analysis, with sociodemographic and lifestyle variables as independent variables. Results: The overall prevalence of participants at risk DSWPDs was 4.3%. Compared with participants without DSWPD, those at risk of DSWPD presented significantly worse HPQ and HRQOL scores. The risk of DSWPD was positively associated with the presence of currently treated diseases, length of nighttime liquid crystal display (LCD) viewing, and being a high school/university students. It was negatively associated with habitual exercise. Conclusion: The risk of DSWPD seemed to be consistent with reports from Western countries, and individuals possibly affected by the disorder were thought to have deteriorated daytime functioning. In addition, lifestyle specific to youth, such as long-term LCD viewing at night and relatively loose social constraints, could be associated with the presence of DSWPD in this generation.

Changes in sleep behavior, sleep problems, and psychological distress/health-related quality of life of young Japanese individuals before and during the COVID-19 pandemic.

Social restrictions during the coronavirus disease (COVID-19) pandemic have impacted sleep behavior and sleep problems, and their related daytime functioning in young adults. However, no studies have examined such changes in young individuals from countries with mild infection intensity and social restrictions. Therefore, we focused on sleep behaviors and sleep issues in young people in Japan. This study was conducted before and after the pandemic (October 2019 and May 2020, respectively). In total, 2,222 (1,371 students and 851 workers) individuals participated and completed anonymous Web-based questionnaires concerning demographic characteristics, sleep behaviors, sleep problems using the Japanese version of the Epworth Sleepiness Scale (JESS) and the Athens Insomnia Scale (AIS-J), psychological distress using the Japanese version of the Kessler Psychological Distress Scale, and health-related quality of life (HRQoL) evaluated with the Short Form-8 (SF-8). A significantly delayed sleep phase was observed in the second survey compared to the first (p < .001) and was more pronounced in students than in workers (p < .001). The total sleep time, social jetlag degree, and JESS, AIS-J, and SF-8 scores were significantly improved after the pandemic (p < .001, p < .001, p < .001, p < .001, p < .05, and p < .001, respectively). Careful monitoring of whether these modest changes can lead to adjustment concerns is needed.

Short sleep duration and irregular bedtime are associated with increased behavioral problems among Japanese preschool-age children.

Sleep problems are known to be risk factors for subsequent emotional and behavioral difficulties in childhood and adolescence. To date, there has been no study investigating the relationships between sleep habits and behavioral problems in a large nonclinical sample of preschool age children. The aim of this study was to examine these relationships and factors associated with the sleep habits of preschool age (2 to 5 year old) children. Their mothers (n = 1,746) completed a multiple-choice questionnaire about the sleep habits and behavior problems of their children, as well as their own sleep habits and working hours at Tokyo metropolitan public nursery schools. The short sleep duration group showed significantly higher aggressive scores than the long sleep duration group among 2- to 3-year-old children, and the irregular bedtime group showed significantly higher aggressive and attention problem scores than the regular bedtime group among 4- to 5-year-old children. Univariate and multivariate logistic regression analyses revealed that children's late bedtime was associated with their mother's late waking-up time, and late schedule of both the mother's leaving and returning home. This study recognized an association between behavioral problems and poor sleep habits among preschool-age children. It is important for children to sleep regularly and adequately in order to decrease their behavior problems. In conclusion, appropriate management of children's sleep by their mothers is necessary for promoting sleep-related health of children.

Correlations among insomnia symptoms, sleep medication use and depressive symptoms.

AIM: To elucidate the factors associated with insomnia symptoms and the use of sleep medication, and the correlations among insomnia symptoms, sleep medication use and depressive symptoms in the general population. METHODS: This survey was conducted in a rural community of Japan. Questionnaires consisted of basic information, the Pittsburgh Sleep Quality Index, and a 12-item version of the Center for Epidemiological Studies Depression scale, and were administered to all community members aged 20 years or over. A total of 2822 respondents with valid answers were subjected to analysis. RESULTS: Occurrence of insomnia symptoms appeared to be associated with advancing age and existence of depressive symptoms. The extent of sleep medication use in the entire sample was 9%, and the value in the subjects with insomnia symptoms was 26%. Sleep medication use in insomniacs was associated with female sex and advancing age as well as higher scores in subcomponents of both poor subjective sleep quality and prolonged delay of sleep onset. Depressive symptoms were worst in the group with insomnia symptoms using sleep medication, and were significantly lower in the group without insomnia symptoms using sleep medication. CONCLUSIONS: Our study revealed that female sex, advancing age, depressive symptoms, poor sleep quality, and prolonged delay of sleep onset appeared as risk factors for sleep medication use. Insomnia symptoms were suspected to act as an exacerbating factor for depressive symptoms. However, our findings suggested that appropriate use of sleep medication could reduce depressive symptoms in the subjects with insomnia symptoms.

Sleep Debt and Social Jetlag Associated with Sleepiness, Mood, and Work Performance among Workers in Japan.

Although sleep debt and social jetlag (SJL) influence daytime dysfunctions, the effects of both sleep debt and SJL on them have not been analyzed. The aim of this study was to examine the mutual relationship between sleep debt and SJL on daytime sleepiness, mood, and work performance. This study was a cross-sectional study on sleep health conducted on the Japanese general population. A total of 4505 general workers (30% female, aged 43.57 ± 11.63 years) were selected and analyzed. Sleep debt was defined by sleep debt index (SDI), which is the discrepancy between desired and real sleep duration. SJL and SDI scores exhibited a positive but weak coefficient (r = 0.19). In a 4 (SJL) × 3 (SDI) two-way ANOVA, the interaction effects were notable for sleepiness and depression scores, while the group effects were notable for the work performance score. For sleepiness and depression scores, SDI >2 h was not significantly different from SJL. In addition, the impact of SDI was higher than that of SJL on sleepiness (ß = 0.17), depression (ß = 0.16), and work performance (ß = -0.10). The impact of sleep debt was more pronounced than SJL on daytime dysfunctions, although both sleep debt and SJL have negative impacts on them.

A Longitudinal Study of Subjective Daytime Sleepiness Changes in Elementary School Children Following a Temporary School Closure Due to COVID-19.

Excessive daytime sleepiness is increasingly being recognized as a major global health concern. However, there have been few studies related to sleepiness and its associated factors in elementary school children. In Japan, all schools were closed from February to May 2020 to prevent coronavirus disease 2019 (COVID-19) outbreaks. The aim of this study was to identify changes in the subjective sleepiness of pupils during the 1.5-year period and to elucidate factors associated with changes in sleepiness. Questionnaire surveys about pupils' sleep habits and the Japanese version of the Pediatric Daytime Sleepiness Scale (PDSS-J) were conducted longitudinally at one elementary school in June 2019, January 2020, and June 2020. The average ∆PDSS score was 0.94 ± 5.51 (mean ± standard deviation) from June 2019 to January 2020 and -1.65 ± 5.71 (t[498] = 6.13, p < 0.01) from January 2020 to June 2020. Univariate and multivariate logistic regression analyses revealed that decreasing social jetlag was associated with decreasing PDSS scores (OR = 0.77, 95% CI: 0.62-0.96, p = 0.02) during the school closure. A less restrictive school schedule secondary to a COVID-19-related school closure decreased sleepiness in children and was associated with decreasing social jetlag.

The Relationship between the Lunar Phase, Menstrual Cycle Onset and Subjective Sleep Quality among Women of Reproductive Age.

The aim of the present study was to investigate the association among lunar cycle, menstrual cycle onset, and subjective sleep quality. Menstrual cycle onset data from the six most recent menstrual cycles were obtained for 529 women (aged 25-39 years) using the smartphone app Luna Luna. We also collected questionnaire survey data on sleep quality from each participant. Overall, there was no association between the onset of menstrual cycle and lunar phase. Interestingly, the proportion of good sleepers with menstrual cycle beginning during the light period was significantly higher than that during the dark period, while the proportion of poor sleepers with menstrual cycle beginning during the dark period was significantly higher than that during the light period. When participants were categorized by the combination of lunar phases (light, dark, neutral periods) in the two most recent menstrual cycle onsets, the "both dark period" group and the "other (light and dark) period" group showed the lowest proportion of good sleepers. Menstrual cycle onset in the dark period was associated with a deterioration in subsequent subjective sleep quality, which was more apparent with consecutive onsets in the dark period or at a rapidly changing lunar phase.

A Cross-Sectional Study of Evening Hyperphagia and Nocturnal Ingestion: Core Constituents of Night Eating Syndrome with Different Background Factors.

This web-based cross-sectional survey aimed to elucidate the differences between the two core symptoms of night eating syndrome (NES): evening hyperphagia and nocturnal ingestion in the general Japanese population aged 16-79 years. Participants who consumed at least 25% of daily calories after dinner were defined as having evening hyperphagia. Those who consumed food after sleep initiation at least twice a week were determined to have nocturnal ingestion. Of the 8348 participants, 119 (1.5%) were categorized in the evening hyperphagia group, 208 (2.6%) in the nocturnal ingestion group, and 8024 in the non-NES group. Participants with evening hyperphagia and nocturnal ingestion had significantly higher anxiety scores (p < 0.05 and p < 0.001, respectively) and depression (p < 0.001 for both) than those without NES. Multiple logistic regression analysis revealed that evening hyperphagia was significantly and independently associated with higher body mass index, shorter sleep duration, later sleep-wake schedule, and higher insomnia score, while nocturnal ingestion was significantly and independently associated with younger age, smoking habit, living alone, earlier sleep-wake schedule, and higher insomnia score. Sleep duration and sleep-wake schedule characteristics in the two groups were opposite, suggesting differences in the sleep pathophysiology mechanisms.

Reliability and validity of the Japanese version of the Biological Rhythms Interview of assessment in neuropsychiatry-self report for delayed sleep-wake phase disorder.

OBJECTIVE: The Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) might be applicable for assessing delayed sleep-wake phase disorder (DSWPD). We aimed to investigate the reliability and validity of the Japanese version of the BRIAN self-report (J-BRIAN-SR) in DSWPD patients and determine a cutoff score to identify the presence of the disorder. METHODS: We enrolled 60 newly diagnosed DSWPD outpatients and 64 age-matched healthy controls. We used Cronbach's alpha for internal reliability to evaluate J-BRIAN-SR. We confirmed the reliability of the A test and re-test using Pearson's correlation coefficient in the controls. We used confirmatory factor analysis to evaluate the factor structure of J-BRIAN-SR and referenced the Morningness-Eveningness Questionnaire (MEQ) to check concurrent validity. We analyzed the receiver operating characteristic curve (ROC) to determine the J-BRIAN-SR cutoff point for the presence of DSWPD. RESULTS: The 18-component scores of the J-BRIAN-SR had an overall reliability coefficient (Cronbach's alpha) of 0.82. We confirmed a high test-retest reliability using an intraclass correlation coefficient (r = 0.84). The correlation between J-BRIAN-SR and MEQ was 0.38 (p = 0.003). The J-BRIAN-SR that we extracted by exploratory factor analysis consisted of three factors. A score of 40 points provided a sensitivity of 80.0% and a specificity of 75.6% for the positivity of DSWPD. CONCLUSIONS: The results of the present study revealed that J-BRIAN-SR is a valid and reliable instrument for screening and evaluating the severity of DSWPD. Our findings will be useful to physicians and patients in Japan and those in clinical settings.

Short sleep duration and long spells of driving are associated with the occurrence of Japanese drivers' rear-end collisions and single-car accidents.

Sleepiness and fatigue are important risk factors for traffic accidents. However, the relation between the accident type and lack of sleep as well as spells of driving has not been examined sufficiently. This study aimed to clarify that short sleep duration and long spells of driving are more associated with rear-end collisions and single-car accidents as compared with accidents of other types in cases of people who cause accidents. After removing drunken driving as a cause of accidents, 1772 parties involved in accidents were questioned. The quantities of rear-end collisions and single-car accidents were, respectively, 240 and 293. Logistic regression analysis showed that short nocturnal sleep (<6 h) and 10-min increments of spells of driving were significantly associated not only with rear-end collisions but also with single-car accidents as compared with accidents of other types. Furthermore, younger age (

Exploring the daily activities associated with delayed bedtime of Japanese university students.

University students show delayed sleep-wake patterns, i.e., later bed- and rise-times, and this pattern is known to be associated with various malfunctions. There may be a variety of daily activities associated with their delayed sleep patterns, such as watching TV. However, it is unclear to what extent each activity possesses an impact on their sleep patterns. The purpose of this study was to determine the daily activities associated with delayed bedtime in Japanese university students who live with or without their families. Three hundred and thirty-one participants were required to record the timing and duration of their sleep and daily activities, and the data from the 275 students (160 men and 115 women; 19.01 +/- 1.66 years) who completely filled forms were used for analysis. The results of multiple regression analyses suggested that interpersonal communication late at night is one of the major factors leading to the delayed bedtime of students living away from home. Among those living with their families, indoor activities such as watching TV and using the Internet were related to their delayed bedtimes. Attending classes and having a morning meal were related to the earlier bedtimes of the students living away from home, but there were no activities associated with those of the students living with their families. These results suggest that ensuring attendance at morning classes and having appropriate mealtimes, as well as restricting the use of visual media and socializing activities at night, are necessary for preventing late bedtimes in university students.