Weekend Oversleep Research Articles

A descriptive study of sleep patterns and knowledge among department of juvenile services staff

Abstract Study Objectives Little is known about sleep health among staff in the US juvenile justice system. Poor sleep health is associated with negative mental and physical health, which may impact daily interactions and treatment of detained youth. The current study explored sleep–wake patterns and sleep health knowledge of Department of Juvenile Services (DJS) staff in Maryland (MD). Methods DJS Staff (N = 218) were invited to complete a survey that queried staff on their own sleep–wake patterns, job role and schedule, and knowledge of youth sleep needs. Descriptive analyses and multivariate analyses of variance (MANCOVA) were conducted to summarize workers’ sleep–wake patterns and examine differences by staff position and schedule. Results Fifty-one percent of staff served as RAs who directly supervise the youth. Just over half (55%) worked in detention and 45% in treatment facilities. Staff reported sleeping 7.24 hours (SD = 4.10) on workdays and 8.59 hours (SD = 2.69) on non-workdays. RA staff working night/rotating versus day shifts reported the most sleep irregularity with larger weekend oversleep times. A little more than half of the staff (53.9%) were knowledgeable regarding youth sleep health with differences by position type. Conclusions Findings show that DJS staff are meeting recommended sleep duration guidelines but are still experiencing sleep schedule and time in bed irregularity. Knowledge variability of youth sleep health across staff may necessitate focused educational programming. Overall, this study may inform future development and prioritization of sleep and circadian health interventions and educational campaigns for staff who work with detained juveniles. This paper is part of the Sleep and Circadian Health in the Justice System Collection.

Poor Sleep Quality, Eveningness, and Anxiety Are Associated With Internet/Smartphone Addiction in Korean Adolescents

Objective: Internet addiction and smartphone addiction are emerging mental health concerns in adolescents. To determine the factors related to these conditions, we investigated their associations with sleep quality, chronotype, sleep patterns, daylight exposure, depression, and anxiety.Methods: Self-rated questionnaires, including the Internet Addiction Proneness Scale-Short Form, Smartphone Addiction Scale–short version, Insomnia Severity Index, Morningness–Eveningness Questionnaire, Epworth Sleepiness Scale, sleep-related questionnaires, and Hospital Anxiety and Depression Scale, were administered in a study population of 1,610 Korean high school students. Multiple linear regression analyses were performed to evaluate the associations with internet addiction and smartphone addiction.Results: Multiple linear regression showed significant associations of internet addiction with poor sleep quality (β=0.094, p<0.001), eveningness (β=-0.071, p=0.006), less daylight exposure (β=-0.066, p=0.005), anxiety (β=0.252, p<0.001), and older age (β=0.295, p<0.001). Smartphone addiction was significantly associated with poor sleep quality (β=0.076, p=0.005), eveningness (β=-0.164, p<0.001), excessive daytime sleepiness (β=0.109, p<0.001), longer time in bed on weekdays (β=0.057, p=0.024), shorter weekend oversleep (β=-0.081, p=0.005), anxiety (β=0.192, p<0.001), and younger age (β=-0.145, p<0.001).Conclusion: Our findings suggest that poor sleep quality, eveningness, and anxiety can serve as predictors of both internet addiction and smartphone addiction in adolescents. Internet addiction seems to be negatively associated with daylight exposure, whereas smartphone addiction showed significant associations with sleep patterns. Additional studies regarding the causal relations between these factors are needed.

A Comprehensive Review of the Literature on Sleep Difficulties and Suicidality in Youth to Inform an Integrative Developmental Model and Future Directions.

Suicide is currently the second leading cause of death among youth. Identification of modifiable near-term risk factors can inform suicide prevention strategies. One promising, readily assessed factor is sleep. We critically review the literature on sleep and suicidal thoughts and behaviors among youth. Most studies examining the youth sleep-suicidality relationship are from epidemiological samples in which both sleep problems and suicidality were assessed over variable timeframes using limited items from scales not designed to measure these constructs. Nonetheless, these data overwhelmingly support an association between suicidality and a range of sleep difficulties (e.g., insomnia, short/long sleep, weekend oversleep), above and beyond depressive symptoms. Limited studies include clinical samples or prospective designs. We review potential mechanisms and present a developmentally-informed integrative model. Literature supports a clear association between sleep difficulties and youth suicidality. Future directions include prospective longitudinal studies and targeted prevention efforts.

Morning preference is associated with subjective happiness among Japanese female workers: A moderation analysis by sleep characteristics from the SLEPT study

ABSTRACT Research on mental health in working populations has predominantly focussed on negative outcomes, while studies on the positive aspects of life remain very limited, especially in Japan. Although morningness has recently been considered a factor for being happy, the role of sleep characteristics as it relates to the association between morningness and happiness has not been substantiated. The aim of this study is to investigate the associations between diurnal preference and level of subjective happiness in healthy, full-time, daytime workers in Japan. We also tested the moderation effect of sleep parameters on the relationship between diurnal preference and subjective happiness. This is an exploratory analysis from the cross-sectional data of the SLeep Epidemiology Project at the University of Tsukuba (SLEPT Study). Subjective happiness was evaluated using a single-item question. Diurnal preference was assessed using the Morningness-Eveningness Questionnaire (MEQ), in which higher scores indicate greater tendency to have morning preference. The participants underwent assessment of sleep parameters for 7 consecutive days using a waist-worn actigraphy device and kept a sleep diary. Sleep parameters investigated were subjective sleep quality, sleep disturbance, daytime sleepiness, weekend oversleep, total sleep time, sleep onset time, wake time, and sleep efficiency. A total of 205 males (average 42.6 ± 10.4 years) and 272 females (41.1 ± 9.8 years) were eligible for analysis. Hierarchical liner regression analysis was used to show the relationships of subjective happiness with MEQ score, and the sleep parameters. Further, moderation analysis was conducted by adding the interaction between MEQ score and the sleep parameters. After adjusting for age, psychological distress, self-rated health, and occupational stress, we found that subjective happiness was significantly associated with higher MEQ score and sleep efficiency but only in female. The moderating role of sleep parameters was not found. We discussed the implications of the obtained results and a possible strategy to maintain and improve subjective happiness of female workers who have evening preference.

Association of Outdoor Artificial Light at Night With Mental Disorders and Sleep Patterns Among US Adolescents

Indoor nighttime light exposure influences sleep and circadian rhythms and is known to affect mood-associated brain circuits in animals. However, little is known about the association between levels of nighttime outdoor light and sleep and mental health in the population, especially among adolescents. To estimate associations of outdoor artificial light at night (ALAN) with sleep patterns and past-year mental disorder among US adolescents. This population-based, cross-sectional study of US adolescents used the National Comorbidity Survey-Adolescent Supplement, a nationally representative cross-sectional survey conducted from February 2001 through January 2004. A probability sample of adolescents aged 13 to 18 years was included. Analyses were conducted between February 2019 and April 2020. Levels of outdoor ALAN, measured by satellite, with means calculated within census block groups. ALAN values were transformed into units of radiance (nW/cm2/sr). Self-reported habitual sleep patterns (weeknight bedtime, weeknight sleep duration, weekend bedtime delay, and weekend oversleep) and past-year mood, anxiety, behavior, and substance use disorders, measured via an in-person structured diagnostic interview. Parent-reported information was included in behavior disorder diagnoses. Among 10 123 adolescents (4953 boys [51.3%]; mean [SE] age, 15.2 [0.06] years [weighted]; 6483 for behavior disorder outcomes), ALAN was positively associated with indicators of social disadvantage, such as racial/ethnic minority status (median [IQR] ALAN: white adolescents, 12.96 [30.51] nW/cm2/sr; Hispanic adolescents: 38.54 [47.84] nW/cm2/sr; non-Hispanic black adolescents: 37.39 [51.88] nW/cm2/sr; adolescents of other races/ethnicities: 30.94 [49.93] nW/cm2/sr; P < .001) and lower family income (median [IQR] ALAN by family income-to-poverty ratio ≤1.5: 26.76 [52.48] nW/cm2/sr; >6: 21.46 [34.38] nW/cm2/sr; P = .005). After adjustment for several sociodemographic characteristics, as well as area-level population density and socioeconomic status, this study found that higher ALAN levels were associated with later weeknight bedtime, and those in the lowest quartile of ALAN reported the longest weeknight sleep duration. Those in the highest quartile of ALAN went to bed 29 (95% CI, 15-43) minutes later and reported 11 (95% CI, 19-2) fewer minutes of sleep than those in the lowest quartile. ALAN was also positively associated with prevalence of past-year mood and anxiety disorder: each median absolute deviation increase in ALAN was associated with 1.07 (95% CI, 1.00-1.14) times the odds of mood disorder and 1.10 (95% CI, 1.05-1.16) times the odds of anxiety disorder. Further analyses revealed associations with bipolar disorder (odds ratio [OR], 1.19 [95% CI, 1.05-1.35]), specific phobias (OR, 1.18 [95% CI, 1.11-1.26]), and major depressive disorder or dysthymia (OR, 1.07 [95% CI, 1.00-1.15]). Among adolescent girls, differences in weeknight bedtime by ALAN (third and fourth quartiles vs first quartile) were greater with increasing years since menarche (F3, 8.15; P < .001). In this study, area-level outdoor ALAN was associated with less favorable sleep patterns and mood and anxiety disorder in adolescents. Future studies should elucidate whether interventions to reduce exposure to ALAN may positively affect mental and sleep health.

Ten-Year Secular Trends in Sleep/Wake Patterns in Shanghai and Hong Kong School-Aged Children: A Tale of Two Cities.

To compare the secular trends of sleep/wake patterns in school-aged children in Hong Kong and Shanghai, two major metropolitan cities in China with two different policies that school start time was delayed in Shanghai, but advanced in Hong Kong in 10 years' time. Participants were from two waves of cross-sectional school-based surveys of children aged 6 to 11 years. In Shanghai, 4,339 and 13,795 children participated in the 2005 and 2014 surveys, respectively. In Hong Kong, 6,231 and 4,585 children participated in the 2003 and 2012 surveys, respectively. Parents reported their children's bedtime and wakeup time, and thus sleep duration, short sleep (≤ 9 hours) and weekend oversleep (difference in sleep duration between weekday and weekend > 2 hours) were determined. Hong Kong children had later bedtime and wakeup time and slept consistently less than their Shanghai counterparts at both survey time points. The shorter sleep duration was particularly marked during weekdays. Over the interval period, weekday sleep duration significantly decreased from 9.2 to 8.9 hours as wakeup time became earlier for Hong Kong children, but increased from 9.4 to 9.6 hours as wakeup time became later for children in Shanghai. Children from both cities slept longer on the weekends. Prevalence of weekend oversleep significantly increased in Hong Kong children, but no interval change was found in Shanghai children. The findings indicate subcultural differences in sleep/wake patterns in Shanghai and Hong Kong school-aged children. In particular, sleep duration had increased for Shanghai children, but decreased for Hong Kong children over 10 years. The benefits and barriers of delaying school start time for optimizing sleep health in school-aged children should be further explored.

Association of asthma and sleep insufficiency among South Korean adolescents: analysis of web-based self-reported data from the Korean youth risk behavior web-based survey

Objectives: Weekend oversleep or catch-up sleep is common among adolescents, but relatively few data are available with regard to its effects on asthma. Our aim was to investigate whether weekend oversleep is associated with ever having asthma among Korean adolescents. Methods: We analyzed web-based self-reported data from the Korean Youth Risk Behavior Web-based Survey in 25,927 physician-diagnosed adolescent asthma cases and 266,160 non-asthma cases. Self-report questionnaires were used to assess socioeconomic status, health behaviors, psychological factors and sleep patterns. Multiple logistic regression after adjusting for factors was used to determine the association between sleep and asthma. Results: The asthma group slept less (≤5 hours: 23.9% vs. 22.8%) had a later weekend bedtime (≥1:00 AM: 58.1% vs. 57.8%), and an earlier weekend wake time (≤7:00 AM: 18.1% vs. 17.0%) compared to the non-asthma group. After multiple logistic regression, a sleep duration ≤5 hours (odds ratio (OR), 1.09; 95% confidence interval (CI), 1.04–1.14) and weekend “early bird” (weekend wake time ≤7:00 AM: OR, 1.03; 95% CI, 1.00–1.07) were significantly associated with an increased frequency of asthma. Long weekend catch-up sleep (weekend sleep duration minus weekday sleep duration ≥2 hours) was significantly associated with a decreased frequency of asthma (OR, 0.98; 95% CI, 0.94–0.99). Conclusion: Long weekend catch-up sleep, as an indicator of insufficient weekday sleep, is associated with a decreased frequency of asthma in Korean adolescents.

Impact of Sleep Duration and Weekend Oversleep on Body Weight and Blood Pressure in Adolescents.

Weekend oversleep or catchup sleep is a frequent occurrence in children, but there are relatively little data concerning its impact on weight and blood pressure. The aim of this study was to assess the association between sleep duration and oversleep, and weight and blood pressure in adolescents. Sleep duration, weight and blood pressure of 327 children (51.4% boys, mean age 13.3 ± 1.7 years) who had polysomnograms performed during both exam cycles of the Tucson Children's Assessment of Sleep Apnea study (TuCASA) were analyzed. Sleep duration on school nights and non-school nights was used to compute a weighted average of child and parent reported overall sleep duration respectively. Oversleep was defined as the difference between self and parent reported weekend sleep and weekday sleep separately. Simple correlations between overall sleep duration, sleep on school and non-school nights and oversleep, and blood pressure, standardized body mass index (BMI), snoring, respiratory disturbance index (RDI) and age were calculated. Significant bivariate associations then were used to develop multivariate partial correlation models. Unadjusted negative correlations with BMI were noted for parent reported total sleep duration at the 1st exam cycle, parent and child reported total sleep and school night sleep duration, and parent reported non-school night sleep duration at the 2nd exam cycle. Additionally, for BMI, positive correlations were observed for log RDI at both exam cycles and snoring at the 2nd exam cycle. For blood pressure, there were positive associations with age, parent reported oversleep, caffeine consumption and snoring. Additionally, for blood pressure, negative relationships were observed with parent reported total sleep duration at the 1st exam cycle, and parent and child reported total sleep and school night sleep durations at the 2nd exam cycle. Partial correlations found that BMI was negatively correlated with parent reported total sleep duration at the 1st exam cycle and parent reported total sleep duration at the 2nd exam cycle, and positively correlated with snoring and log RDI at both exam cycles. Systolic blood pressure was only associated with age and snoring. Diastolic blood pressure was positively correlated with age and caffeine consumption, and negatively correlated with parent reported total and school night sleep duration. Oversleep and child reported sleep duration were not represented in any of these models. Lower amounts of sleep especially on school nights is associated with higher body weight and blood pressure. Oversleep was not associated with either body weight or blood pressure.

Sleep Patterns and Mental Health Correlates in US Adolescents

To investigate systematically the associations of sleep patterns with a range of mental disorders and other outcomes among a nationally representative sample of US adolescents. Using the National Comorbidity Survey Adolescent Supplement, a nationally representative cross-sectional survey of 10 123 US adolescents 13-18 years of age, we assessed associations between adolescent-reported sleep patterns (tertiles of weeknight bedtime, weeknight sleep duration, weekend bedtime delay, and weekend oversleep) and past-year mental disorders based on the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, smoking, injury, suicidality, and perceived mental and physical health, assessed via direct diagnostic interview. The average weeknight bedtime was at 22:37 and sleep duration was 7.72 hours. Average weekend bedtime delay was 1.81 hours and average weekend oversleep was 1.17 hours. Later weeknight bedtime, shorter weeknight sleep duration, greater weekend bedtime delay, and both short and long periods of weekend oversleep were associated with increased odds of mood, anxiety, substance use, and behavioral disorders, as well as suicidality, tobacco smoking, and poor perceived mental and physical health. ORs ranged from 1.27 to 2.15. The only outcomes not associated with any sleep patterns were past-year injury and eating disorder. Suboptimal sleep patterns were associated with an array of mental disorders and other health-related outcomes among adolescents. Abnormal sleep patterns may serve as markers of prodromal or untreated mental disorders among adolescents, and may provide opportunities for prevention and intervention in mental disorders.

Academic performance among adolescents with behaviorally induced insufficient sleep syndrome.

The present study investigated academic performance among adolescents with behaviorally induced insufficient sleep syndrome (BISS) and attempted to identify independent predictors of academic performance among BISS-related factors. A total of 51 students with BISS and 50 without BISS were recruited from high schools in South Korea based on self-reported weekday sleep durations, weekend oversleep, and the Epworth Sleepiness Scale (ESS). Participants reported their academic performance in the form of class quartile ranking. The Korean version of the Composite Scale (KtCS) for morningness/eveningness, the Beck Depression Inventory (BDI) for depression, and the Barratt Impulsiveness Scale-II (BIS-II) for impulsivity were administered. Adolescents with BISS reported poorer academic performance than adolescents without BISS (p = 0.02). Adolescents with BISS also exhibited greater levels of eveningness (p < 0.001), depressive symptoms (p < 0.001), and impulsiveness (p < 0.01). Longer weekend oversleep predicted poorer academic performance among adolescents with BISS even after controlling for ESS, KtCS, BDI, and BIS-II (β = 0.42, p < 0.01). BISS among adolescents is associated with poor academic performance and that sleep debt, as represented by weekend oversleep, predicts poorer academic performance independent of depression, impulsiveness, weekday sleep duration, daytime sleepiness, and morningness/eveningness among adolescents with BISS.

Determinants of Sleep Duration Among High School Students in Part‐Time Employment

ABSTRACTAdolescents who work while attending school are reported to sleep less than those who do not. This study aimed to identify factors associated with short sleep duration in students who work during the school year. A cross‐sectional survey aiming to describe working conditions and occupational safety and health was completed by representative samples of Quebec high school students aged 12–19 years from three administrative regions (n = 3,871). A multiple stepwise regression analysis was performed with sleep duration as the dependent variable, and sociodemographic, school, occupational, and health factors as potential explanatory variables. Significant factors associated with shorter sleep duration were later bedtimes (p &lt; .001), shorter weekend oversleep (p &lt; .001), higher physical work factors related to handling efforts (p &lt; .001), and female gender (p &lt; .01). Addressing work conditions of student workers may help prevent sleep deprivation. Special efforts should also target girls combining work and study.

Objective and Subjective Socioeconomic Gradients Exist for Sleep Quality, Sleep Latency, Sleep Duration, Weekend Oversleep, and Daytime Sleepiness in Adults

Socioeconomic gradients exist for multiple health outcomes. Lower objective socioeconomic position (SEP), whether measured by income, education, or occupation, is associated with inadequate sleep. Less is known about whether one's perceived ranking of their social status, or subjective SEP, affects sleep. This study examined whether a subjective socioeconomic gradient exists for sleep while controlling for objective SEP. Participants (N = 177; age, M = 45.3 years, SD = 6.3 years) completed the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, MacArthur Ladder, and other self-report measures to assess sleep and objective SEP. Subjective SEP trumped objective SEP as a better predictor of sleep duration, daytime sleepiness, and weekend oversleep. These findings highlight the need to expand our framework to better understand the mechanisms underlying socioeconomic gradients and sleep.

Longitudinal bi-directional relationships between sleep and youth substance use.

Despite the known deficits in sleep that occur during adolescence and the high prevalence of substance use behaviors among this group, relatively little research has explored how sleep and substance use may be causally related. The purpose of this study was to explore the longitudinal bi-directional relationships between sleep duration, sleep patterns and youth substance use behaviors. Participants included 704 mostly white (86.4 %) youth, 51 % female, with a baseline mean age of 14.7 years. Self-reported substance use behaviors included past month alcohol, cigarette, and marijuana use. Sleep measures included sleep duration on weekends and weekdays, total sleep, weekend oversleep, and weekend sleep delay. Cross-lagged structural equation models, accounting for clustering at the school level, were run to determine the longitudinal association between sleep and substance use adjusting for socio-demographic characteristics, pubertal status, body mass index z-score, and depressive symptoms. Cigarette use and weekend sleep were bi-directionally related as were marijuana use and total sleep. No other bi-directional associations were identified. However, alcohol use predicted shorter weekend oversleep and marijuana use predicted increased weekend sleep and weekend oversleep. Sleep patterns and duration also predicted adolescents' cigarette, alcohol, and marijuana use. Sleep, both patterns and duration, and substance use among youth are intertwined. Future research is needed to explore these bi-directional relationships, as well as other important contextual factors that may moderate these associations.

Insufficient Sleep and Suicidality in Adolescents

To investigate the association between the behaviorally induced insufficient sleep and suicidality among adolescents. A population-based, cross-sectional survey. General community. A sample of 8,530 students (grades 7-11) was recruited in the Republic of Korea. The participants were 8,010 students who completed all questionnaires. N/A. The survey included the Beck Scale for Suicidal Ideation (SSI), the Beck Depression Inventory (BDI), a modified Epworth Sleepiness Scale (ESS), and questionnaires about sleep (weekday/weekend sleep schedule/duration, insomnia and snoring). Adolescents with behaviorally induced insufficient sleep syndrome (BISS) had higher SSI scores than those who slept ≥ 7 hours on weekdays, even after controlling for age, sex, and BDI score (F = 11.71, P < 0.001). After controlling for age and sex, longer weekend oversleep and shorter weekday sleep duration predicted a higher SSI score (β = 0.19, P < 0.001; β = 0.37, P < 0.001). The association between weekend oversleep and SSI score remained significant even after additionally controlling for BDI and ESS scores and presence of insomnia and snoring (β = 0.07, P < 0.01). BISS was found to be associated with increased suicidality. Weekend oversleep was associated with suicidality independently of depression, daytime sleepiness, snoring, and insomnia. The study findings suggest that chronic sleep restriction among adolescents may increase suicidal risk.

Proactive People Are Morning People1

Proactivity is the willingness and ability to take action to change a situation to one's advantage and has been studied in a wide range of contexts. The role of chronotype on proactivity has not been assessed. Individual differences in circadian rhythms have been widely acknowledged and are accepted as an interesting facet of human personality. Morning people were more proactive than evening types, and people with small differences in rise time between weekdays and free days were also more proactive persons. Sleep length (on weekdays and on free days) and total time spent in weekend oversleep did not show any relationship with proactivity. These results suggest that morning people are more proactive than are evening types.

Sleep-Wake Patterns and Sleep Disturbance among Hong Kong Chinese Adolescents

To determine sleep-wake patterns and evaluate sleep disturbance in Hong Kong adolescents; to identify factors that are associated with sleep disturbance; and to examine the relationship of sleep-wake variables and academic performance. A school-based cross-sectional survey. Sample included 1629 adolescents aged 12 to 19 years. Self-report questionnaires, including sleep-wake habit questionnaire, Sleep Quality Index, Morningness/ Eveningness scale, Epworth Sleepiness Scale, Perceived Stress Scale, academic performance, and personal data were administered. The average school-night bedtime was 23:24, and total sleep time was 7.3 hr. During weekends, the average bedtime and rise time was delayed by 64 min and 195 min, respectively. The prevalence of sleep disturbances occurring > or = 3 days per week in the preceding 3 months were: difficulty falling asleep (5.6%), waking up during the night (7.2%), and waking up too early in the morning (10.4%). The prevalence of > or = 1 of these three symptoms was 19.1%. Stepwise regression analyses revealed that circadian phase preference was the most significant predictor for school night bedtime, weekend oversleep, and daytime sleepiness. Perceived stress was the most significant risk factor for sleep disturbance. Students with marginal academic performance reported later bedtimes and shorter sleep during school nights, greater weekend delays in bedtime, and more daytime sleepiness than those with better grades. The prevalence of sleep deprivation and sleep disturbance among Hong Kong adolescents is comparable to those found in other countries. An intervention program for sleep problems in adolescents should be considered.

Differences in Sleep and Circadian Preference between Eastern and Western German Adolescents

Only a few studies focus on comparisons to reveal differences in sleep and circadian preferences in adolescents. This study used the same instrument to compare adolescents in Eastern and Western Germany. In all, 674 pupils between 11 and 16 yrs participated. The questionnaire asked questions about wake times and bed times (on weekend and weekdays), and the Composite Scale of Morningness (CSM) was completed to assess diurnal preferences. Locality (East/West Germany) had no effect on rise and bed times during the week and on sleep length on the weekend. Western pupils rose later on weekends and went to bed later on weekends. While sleep length on weekdays was shorter in West Germany, weekend oversleep was longer and misalignment was higher. Diurnal preferences (CSM scores) suggested a higher eveningness in West Germany. As interaction effects were insignificant, changes throughout adolescence seem similar in East and West Germany. These data suggest that given similar school start times, Western German pupils are at higher risk because they are later chronotypes. The finding of earlier rise and bed times of the East German pupils is consistent with the hypothesis that sunlight acts as the entrainment for the biological clock of adolescents, as sunrise is earlier in Eastern Germany.

Sleep and Risk-Taking Behavior in Adolescents

The primary purpose of this study was to examine the relationship between adolescents' sleep-wake patterns and risk-taking behavior. A second goal was to replicate the results obtained by Wolfson and Carskadon (1998) regarding adolescents' sleep habits. Three hundred eighty-eight adolescents (217 males, 171 females) completed the Sleep Habits Survey and the Youth Risk Behavior Survey. The results indicated that adolescents who reported longer weekend delay and higher levels of sleep problems also reported significantly higher levels of risk-taking behaviors, and students' weekend delay was also related to their academic performance in this sample. As in the sample studied by Wolfson and Carskadon (1998), the adolescents in this study exhibited changes in both weekday and weekend sleep habits across grade/age. However in the present study, only school-night total sleep time and weekend delay were related to adolescents' daytime functioning, with no significant relationships being found between weekend oversleep and daytime functioning. This provides partial support for the findings of Wolfson and Carskadon (1998). Overall, sleep-wake patterns were found to relate to risk-taking behavior during adolescence in this study.

Age-Related Changes in Sleep/Wake Patterns Among Korean Teenagers

As children go through the transition from childhood to adolescence, many shifts occur in sleep/wake patterns related to intrinsic and extrinsic developmental changes. These shifts have been shown to result in corresponding shifts in sleep phase (later sleep onset) and sleep deprivation among teenagers in Western societies. However, the effect of these developmental changes on the sleep habits of Korean teenagers has not been analyzed. This study aims to quantify age-related changes in sleep/wake patterns among Korean teenagers and elucidate cultural and other factors causing these changes. The School Sleep Habits Survey was administered in homeroom classes to students in grades 5 to 12 (mean age: 13.7 +/- 2.4 years) selected via a 2-way stratification sampling method. The survey included items regarding usual sleep/wake patterns over the previous 2 weeks as well as measures of daytime sleepiness, sleep/wake-problem behavior, depressed mood, and morningness/eveningness. A total of 1457 students (52.9% male) completed the survey. The higher the grade, the later bedtime was found to be on both school days and weekends. There was a similar relationship between increasing grade and earlier wake time on school days, but higher grades were associated with later wake time on weekends. Total sleep time decreased by approximately 3 hours on school nights and 1 hour on weekend nights from grades 5 to 12. Adolescents were severely sleep deprived, with mean school-night total sleep times of 6.02, 5.62, and 4.86 hours for 10th-, 11th-, and 12th-graders, respectively. In the higher grades, there was a greater discrepancy between school nights and weekends in terms of bedtime and wake time, and the magnitude of weekend oversleep increased. Older students also reported more daytime sleepiness, more sleep/wake-problem behavior, more depressed mood, and more eveningness preference. The chief reasons students cited for their sleep deprivation differed across grades: Academic demands and entertainment (such as Internet and television) were reported by 5th- and 6th-graders, entertainment and then academic demands by 7th-, 8th-, and 9th-graders, and early school start time and academic demands by 10th-, 11th- and 12th-graders. This study clearly demonstrates that Korean adolescents do not get adequate sleep and that they have profound discrepancies in their sleep/wake patterns between school and weekend nights. Compared with previous studies from other countries, Korean students display even greater sleep deprivation and also more irregular sleep/wake patterns. This study also demonstrates that academic demands/stress and early school start time are the most important contributing factors for sleep deprivation among Korean adolescents. These findings stress the need to promote awareness of the magnitude of adolescent sleep deprivation and its detrimental effects in Korean society.