Associations between sleep habits and mental health status and suicidality in a longitudinal survey of monozygotic twin adolescents

Role of sleep problem on suicidal behaviour and non-suicidal self-injury among adolescents in Pokhara, Nepal

INTRODUCTION

Sleep is a fundamental human requirement, considered one of the major contributing factors to physical and mental health, especially among adolescents. Poor quality sleep has many potential consequences including non-suicidal self-injury (NSSI), suicidal thoughts or behaviour and complete suicide. The NSSI and suicidal behaviour are increasing in Nepal. Thus, this study aimed to assess the role of sleep problem on suicidal behaviour and non-suicidal self-injury among adolescents in Pokhara metropolitan, Nepal.

METHODS

A cross-sectional analytical study was conducted among 673 adolescents using a multistage cluster sampling technique from private and public schools in Pokhara Metropolitan. Self-administered questionnaire was used for data collection. Collected data was entered and managed in EpiData (version 3.1) and analysed in IBM SPSS (version 23). Binary logistic regression was used to identify the association of sleep problem with NSSI and suicidal behaviour.

RESULTS

The study found that sleep problem (65.2%, 439), suicidal behaviour (18.6%, 125) and NSSI (57.9%, 390) were prevalent among adolescents in study setting. The presence of sleep problem significantly influenced the suicidal behavior (AOR = 3.88, 95% CI = 2.27-6.63) alongside the sex of student (AOR = 1.96, 95% CI = 1.28-3.00), adolescents from family having monthly income less than NPR 40,000 (AOR = 1.97 95% CI = 1.16-3.35) and private schools students (AOR = 2.99, 95% CI = 1.84-4.86). Likewise, sleep problem was also associated with non-suicidal self-injury (AOR = 3.24, 95% CI = 2.26-4.65), in addition to attending private school (AOR = 2.52, 95% CI = 1.71-3.72).

CONCLUSION

This study concludes that sleep problem is prevalent among the adolescents and increase the risk of NSSI and suicidal behaviour. Therefore, parents and teachers need to assess their conditions and help them maintain sound sleep. Additionally, suicide prevention strategies need to be adopted to mitigate further risk.

Association of sleep and generalized anxiety disorder in Korean adolescents

BACKGROUND

Generalized anxiety disorder (GAD) is a common anxiety disorder among adolescents, significantly impacting their concentration and learning capabilities. The connection between emotional well-being and sleep is well-established, and Korean adolescents are particularly prone to inadequate sleep. This study aimed to determine the association between sleep duration and GAD in Korean adolescents.

METHODS

This study was conducted using data from 106,513 adolescents aged 12-18 years. Data from the 2020-2022 Korea Youth Risk Behavior Survey were used. Sleep duration was classified into five groups, based on an average sleep duration of 7-7.9 h in adolescents. Social jet lag was defined as a misalignment between an individual's biological and social clocks. Differences in sleep duration between weekdays and weekends, social jet lag, and bedtime were each classified into three categories. Multiple logistic regression analysis was performed to evaluate the association between sleep duration and GAD.

RESULTS

Comparing the five groups classified based on sleep duration, adolescents in the groups that slept less experienced a significant increase in the odds of developing GAD (adjusted odds ratio [aOR]: boys: 1.10 in the 6.0-6.9-h group, 1.14 in the 5.0-5.9-h group, and 1.23 in the ≤ 4.9-h group; girls: 1.05 in the 6.0-6.9-h group, 1.19 in the 5.0-5.9-h group, 1.22 in the ≤ 4.9-h group). Adolescents with poor sleep quality experienced more frequent instances of inadequate sleep (aOR: boys: 2.51; girls: 2.43).

CONCLUSIONS

GAD is strongly associated with insufficient sleep. Consequently, it is imperative to assess and address GAD in adolescents with irregular sleep patterns.

The role of victimisation and sleep quality in self-harm and depression among sexual minority adolescents. A prospective cohort study

Sexual minority adolescents (SMA) have a disproportionately high prevalence of victimisation, self-harm, and depressed mood, relative to the general population. Yet, the contributing and mechanistic factors are unclear. We aim to explore the directional relationship between victimisation and self-harm and depressed mood, with poor sleep quality as a possible mediator. A secondary data analysis was conducted using a nationally representative birth cohort in the United Kingdom, where participants self-identified as sexual minority (N = 1922, aged 11-13, 67.1% female) and their parents completed questionnaires and interviews when the participants were aged 11, 14 and 17. Logistic and linear regression were used to test whether victimisation prospectively predicted self-harm and depressed mood with mediation analyses conducted to assess if sleep onset latency and nocturnal awakening mediated their relationships. After adjusting for demographic factors and baseline self-harm and depressed mood, victimisation at age 11 significantly predicted self-harm (OR = 1.40, p < .01) and depressed mood (B = 0.024, SE = 0.01, p < .05) at age 17. In the mediation analyses, frequent nocturnal awakening at age 14, but not sleep onset latency, significantly mediated the effect of victimisation at age 11 on self-harm (indirect effect B = 0.008, SE = 0.004, 95%CI = 0.001-0.017) and depressed mood (indirect effect B = 0.005, SE = 0.002 95%CI = 0.001-0.010) at age 17. Our findings supported that victimisation contributed to negative mental health among SMA. Poor sleep quality could be an indicator of maladjustment with victimisation, which further increased vulnerability to negative mental health. Victimisation and sleep quality could be important assessment targets in mental health campaign among sexual minority adolescents.

Normal Sleep in Children and Adolescence

Adequate sleep is essential for healthy development in childhood and adolescence. Healthy sleep contributes to good physical health, immune function, mental health, and academic performance. The regulation and architecture of sleep change greatly across childhood and adolescence, and the ability to obtain sufficient sleep is impacted by a range of factors that change with maturation. This article describes normal sleep across childhood and adolescence and discusses some of the most common barriers to adequate sleep, including early school start times, technology use, and changes to circadian rhythms, and sleep homeostasis across puberty.

When Night Falls Fast: Sleep and Suicidal Behavior Among Adolescents and Young Adults

Sleep disturbances have been linked to suicidal ideation and behaviors in adolescents. Specifically, insomnia and nightmares are associated with current suicide risk and predict future ideation. Associations between hypersomnia, sleep apnea, and suicide remain inconclusive. Potential biological mechanisms underlying these relationships include executive functioning deficits and hyperarousal. Related psychological factors may include thwarted belongingness, perceived burdensomeness, and negative appraisals. Assessing suicide risk in patients with sleep disturbances, and vice versa, is needed. Therapeutic interventions such as cognitive behavior therapy for insomnia and imagery rehearsal treatment, as well as pharmacologic treatments, show promise in treating sleep disorders and suicidal behavior.

Within-Person Variability Score-Based Causal Inference: A Two-Step Estimation for Joint Effects of Time-Varying Treatments

Behavioral science researchers have shown strong interest in disaggregating within-person relations from between-person differences (stable traits) using longitudinal data. In this paper, we propose a method of within-person variability score-based causal inference for estimating joint effects of time-varying continuous treatments by controlling for stable traits of persons. After explaining the assumed data-generating process and providing formal definitions of stable trait factors, within-person variability scores, and joint effects of time-varying treatments at the within-person level, we introduce the proposed method, which consists of a two-step analysis. Within-person variability scores for each person, which are disaggregated from stable traits of that person, are first calculated using weights based on a best linear correlation preserving predictor through structural equation modeling (SEM). Causal parameters are then estimated via a potential outcome approach, either marginal structural models (MSMs) or structural nested mean models (SNMMs), using calculated within-person variability scores. Unlike the approach that relies entirely on SEM, the present method does not assume linearity for observed time-varying confounders at the within-person level. We emphasize the use of SNMMs with G-estimation because of its property of being doubly robust to model misspecifications in how observed time-varying confounders are functionally related to treatments/predictors and outcomes at the within-person level. Through simulation, we show that the proposed method can recover causal parameters well and that causal estimates might be severely biased if one does not properly account for stable traits. An empirical application using data regarding sleep habits and mental health status from the Tokyo Teen Cohort study is also provided.

Sleep quality and internet addiction among junior college students; The mediating role of depression: A cross-sectional study

This study investigated the mediating effect of depression on the relationship between sleep quality and internet addiction in Taiwanese junior college students. We recruited 590 (53 males, 537 females) students, aged from 15 to 22 years from a day school of a junior college in northern Taiwan. We used a cross-sectional study design. The Chen Internet Addiction Scale, Chinese Version of the Pittsburgh Sleep Quality Index, and Adolescent Depression Scale were used as measurement instruments. Using the IBM SPSS Statistics 26 software package, descriptive statistics, reliability analysis, correlation analysis, and inferential statistics were used to evaluate the participants' demographics and relationships between the study variables. The mediation model was tested using the Z test. The prevalence of internet addiction in junior college students was 21.2 %. The indirect effects were determined using Sobel's test and bootstrapping confirming that depression completely mediated the relationship between sleep quality and internet addiction. The findings would help to build holistic and comprehensive prevention and intervention programs that should be developed to reduce the addictive behaviors of adolescents.

Interactive effects of sleep and physical activity on depression among rural university students in China

Background

Decreased sleep quality and physical activity among university students have become important concerns, while depressive symptoms are on the rise, especially in rural areas. Previous studies have confirmed the association between sleep quality and physical activity and depressive symptoms, but the effect of their interaction on depressive symptoms has been less studied. For this reason, the present study analyzed the interaction between sleep quality and physical activity on depressive symptoms to provide reference and assistance for mental health promotion and intervention for university students in rural areas of China.

Methods

In this study, we investigated sleep quality, physical activity, and depressive symptoms in 11,423 university students in rural areas of China. The association of sleep quality and physical activity with depressive symptoms was analyzed by using univariate analysis and logistic regression analysis. And further analyzed the association between the interaction effect of sleep quality and physical activity and depressive symptoms.

Results

The proportion of university students with depressive symptoms in rural China was 33.3%, with a higher proportion of girls students (36.7%) having depressive symptoms than boys students (28.8%). Logistic regression analysis of the interaction between sleep quality and physical activity and depressive symptoms in university students showed that university students with poor sleep quality and MVPA>60 min/d (OR = 4.40,95% CI: 3.75-5.05) had the highest risk of depressive symptoms (p < 0.001). University students with moderate sleep quality and MVPA of 30-60 min/d (OR = 1.18, 95% CI: 0.75-1.61) had the lowest risk of depressive symptoms (p < 0.001). Moreover, there was no gender difference in this result.

Conclusion

The prevalence of depressive symptoms was higher among university students in rural areas of China. There was an interaction between sleep quality and MVPA on depressive symptoms, maintaining a good quality of sleep and an appropriate length of MVPA has a contributory effect on mental health, and the same trend was found for both boys and girls students. It is recommended that university students in rural areas of China should first maintain proper sleep quality while maintaining 30-60 min of MVPA per day, which may reduce the risk of depressive symptoms.

Insomnia, sleep duration, and risk of anxiety: A two-sample Mendelian randomization study

BACKGROUND

The effect of insomnia and sleep duration on risk of anxiety has been assessed based on traditional epidemiological studies. However, the inconsistent conclusions do not establish causal associations. This study aimed to explore the causal associations of insomnia, short sleep, and long sleep with anxiety.

METHODS

We used summary statistics from three large-scale genome-wide association studies (GWAS) of European ancestry to perform a two-sample Mendelian randomization (MR) study. MR analyses were mainly conducted with the inverse-variance-weighted (IVW) method. To evaluate the robustness of our findings, we performed the weighted-median approach, the MR-Egger method, and the MR-robust adjusted profile score (MR-RAPS) method for sensitivity analyses.

RESULTS

There was a statistically significant association of genetically predicted insomnia with anxiety using the IVW method (OR = 1.36, 95% CI = 1.23-1.51, P < 0.001). Genetically predicted short sleep was potentially associated with anxiety using IVW method (OR = 1.67, 95% CI = 1.08-2.60, P = 0.022). However, sensitivity analyses did not find the causal association of short sleep with anxiety (all P > 0.053). We did not observe a statistically significant causal association of genetically predicted long sleep with anxiety (OR = 0.91, 95% CI = 0.48-1.74, P = 0.775).

CONCLUSIONS

We found strong evidence that insomnia but not short sleep and long sleep has a causal effect on anxiety. The characteristics of insomnia should be incorporated into anxiety prevention and intervention strategies, which have important public health significance.

Device-measured sleep onset and duration in the development of depressive symptoms in adolescence

BACKGROUND

Sleep deprivation in adolescence is increasing in prevalence and may be linked to subsequent depression. Findings regarding associations between sleep duration, sleep onset time, and the development of depressive symptoms over time in adolescents are mixed, and rely on subjective measures of sleep.

METHODS

Sleep onset and duration were assessed using a combined heart rate monitor and accelerometer and self-report in 688 participants from the ROOTS study at age 15. Participants reported depressive symptoms at ages 14.5, 16, and 17.5, using the Mood and Feelings Questionnaire. Latent growth curve modelling was used to model development of depressive symptoms and test associations with baseline sleep onset and duration.

RESULTS

Cross-sectionally, falling asleep later and shorter sleep duration were both associated with higher depressive symptoms in males and females, using both device-measured and self-reported sleep. There were no longitudinal associations between baseline sleep duration and change in depressive symptoms. A later sleep onset-time was associated with a decrease in depressive symptoms over time, in females only, using device-measured sleep only.

LIMITATIONS

The current sample was more economically advantaged and ethnically white than the UK average, and with lower MFQ symptoms than the original cohort, which may reduce generalisability.

CONCLUSIONS

Adolescents who fall asleep later or sleep less have higher levels of depressive symptoms cross-sectionally, but do not show increases in depressive symptoms over time. Interventions targeting sleep onset and duration in adolescence may improve mental health in the short-term but the possibility of reverse causality should be explored further.

The quality of sleep and daytime sleepiness and their association with quality of school life and school achievement among students

BACKGROUND

Sleep quality is an important factor in adolescents' health; physical as well as psychological. The aim of this study was to determine sleep quality and daytime sleepiness and their effect on the quality of school life (QSL) and achievement.

MATERIALS AND METHODS

This cross-sectional study was conducted in high schools. The data collection was done on a random sample of 500 students from 15 to 19 years. The questionnaires included the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality and the Epworth Sleepiness Scale to measure daytime sleepiness as well as QSL. Data were analyzed by SPSS 25. Linear and logistic regressions were used to obtain adjusted and unadjusted odds ratios as well as predictors.

RESULTS

The mean PSQI score was 6.2 ± 2.4. It was realized that 377 participants (75.4%) were poor sleepers; 6.2% had excessive daytime sleepiness. There was a significant association between age and quality of sleep (P < 0.04). No association between gender and quality of sleep or between the quality of sleep and school achievement was found. Linear regression exhibited a significant relationship between the quality of sleep and daytime sleepiness (β = 0.218; t = 4.982, P = 0.000). There was a significant, inverse correlation between sleepiness and the total score of QSL (P = 0.000). Stepwise linear regression analysis exhibited that daytime sleepiness (P = 0.002) and school achievement (P = 0.001) were predictors of QSL.

CONCLUSION

According to the study results, sleepiness affects school performance and QSL, and on the other hand, daytime sleepiness is under the effect of sleep quality.

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

Purpose of Review

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.

Recent Findings

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.

Summary

Literature supports a clear association between sleep difficulties and youth suicidality. Future directions include prospective longitudinal studies and targeted prevention efforts.

Associations between Sleep and Mental Health in Adolescents: Results from the UK Millennium Cohort Study

(1) Background: There is a growing interest in investigating the relationship between sleep and mental health development in adolescents. This study aims to further investigate this relationship by identifying the specific associations between several sleep problems in adolescents and several mental health areas, and the role of gender in these associations. (2) Methods: Data from the Millennium cohort survey containing 11,553 individuals at 13–14 years old was included. Nighttime sleep duration and bedtime during weekdays and weekends, night awakening frequency, and sleep onset latency were assessed using self-reported questionnaires. Affective symptom and emotional and behavioural problems were examined with self-reported questionnaires. (3) Results: Regression analyses and path analysis models suggested that frequent night awakening was associated with all the outcomes, and hyperactivity/inattention was the outcome that presented a higher number of significant associations with sleep patterns. Long sleep onset latency and late bedtime at school days were associated with higher risk of emotional and behavioural difficulties. Further, poor sleep seems to manifest more externally in males, while more internally in females. (4) Conclusions: Specific sleep problems should be considered when assessing mental health in adolescence, which would allow more targeted prevention and intervention strategies. Further, special attention should be given to gender differences when addressing sleep and mental health.

How does the COVID-19 affect mental health and sleep among Chinese adolescents: a longitudinal follow-up study

OBJECTIVE

The Corona Virus Disease-19 (COVID-19) pandemic has evolved into the largest public health event in the world. Earlier COVID-19 studies have reported that the pandemic caused widespread impacts on mental health and sleep in the general population. However, it remains largely unknown how the prevalence of mental health problems and sleep disturbance developed and interacted in adolescents at different times in the epidemic.

METHODS

831 teenagers (aged 14-19) underwent a longitudinal follow-up study to evaluate the prevalence of mental health problems and sleep disturbance among adolescents before, during, and after the COVID-19 breakout in China and to explore the interaction between mental health and sleep across the three measurements. The chronotype, anxiety and depression level, sleep quality, and insomnia were investigated during each measurement.

RESULTS

The adolescents had delayed sleep onset and sleep offset time, longer sleep duration during the quarantine than before and after the epidemic, whereas their chronotype tended to morning type during the epidemic. Yet, the highest prevalence of anxiety, depression, poor sleeper, and insomnia symptoms were observed before but not during the COVID-19 breakout. The females and adolescents who were eveningness type showed significantly higher anxiety and depression levels, poorer sleep quality, and severe insomnia status than the males and the intermediate and morning types. Sleep disturbance was positively associated with mental problems among three measurements. Pre-measured depression level significantly predicted sleep disturbance level at follow-ups.

CONCLUSION

These findings suggested that adolescents' high prevalence of mental health and sleep problems occurred before the COVID breakout and decreased during and after the epidemic. Gender and chronotype were significant risk factors associated with affective and sleep disturbances. Depression positively predicted later sleep problems, but not vice versa.

Associations of sleep phenotypes with severe intentional self-harm: a prospective analysis of the UK Biobank cohort

STUDY OBJECTIVES

We aimed to investigate the prospective associations of sleep phenotypes with severe intentional self-harm (ISH) in middle-aged and older adults.

METHODS

A total of 499,159 participants (mean age: 56.55 ± 8.09 years; female: 54.4%) were recruited from the UK Biobank between 2006 and 2010 with follow-up until February 2016 in this population-based prospective study. Severe ISH was based on hospital inpatient records or a death cause of ICD-10 codes X60-X84. Patients with hospitalized diagnosis of severe ISH before the initial assessment were excluded. Sleep phenotypes, including sleep duration, chronotype, insomnia, sleepiness, and napping, were assessed at the initial assessments. Cox regression analysis was used to estimate temporal associations between sleep phenotypes and future risk of severe ISH.

RESULTS

During a follow-up period of 7.04 years (SD: 0.88), 1,219 participants experienced the first hospitalization or death related to severe ISH. After adjusting for demographics, substance use, medical diseases, mental disorders, and other sleep phenotypes, short sleep duration (HR: 1.50, 95% CI: 1.23-1.83, P < .001), long sleep duration (HR: 1.56, 95% CI: 1.15-2.12, P = .004), and insomnia (usually: HR: 1.57, 95% CI: 1.31-1.89, P < .001) were significantly associated with severe ISH. Sensitivity analyses excluding participants with mental disorders preceding severe ISH yielded similar results.

CONCLUSION

The current study provides the empirical evidence of the independent prediction of sleep phenotypes, mainly insomnia, short and long sleep duration, for the future risk of severe ISH among middle-aged and older adults.

Associations of sleep with psychological problems and well-being in adolescence: causality or common genetic predispositions?

BACKGROUND

Whereas short and problematic sleep are associated with psychological problems in adolescence, causality remains to be elucidated. This study therefore utilized the discordant monozygotic cotwin design and cross-lagged models to investigate how short and problematic sleep affect psychological functioning.

METHODS

Adolescent twins (N = 12,803, 13-20 years, 42% male) completed questionnaires on sleep and psychological functioning repeatedly over a two-year interval. Monozygotic twin pairs were classified as concordant or discordant for sleep duration and trouble sleeping. Resulting subgroups were compared regarding internalizing problems, externalizing problems, and subjective well-being.

RESULTS

Cross-sectional analyses indicated associations of worse psychological functioning with both short sleep and problematic sleep, and cross-lagged models indicate bidirectional associations. Longitudinal analyses showed that an increase in sleep problems experienced selectively by one individual of an identical twin pair was accompanied by an increase of 52% in internalizing problem scores and 25% in externalizing problem scores. These changes were significantly different from the within-subject changes in cotwins with unchanged sleep quality (respectively, 3% increase and 5% decrease). Psychological functioning did, however, not worsen with decreasing sleep duration.

CONCLUSIONS

The findings suggest that sleep quality, rather than sleep duration, should be the primary target for prevention and intervention, with possible effect on psychological functioning in adolescents.

Normal Sleep in Children and Adolescence

Adequate sleep is essential for healthy development in childhood and adolescence. Healthy sleep contributes to good physical health, immune function, mental health, and academic performance. The regulation and architecture of sleep change greatly across childhood and adolescence, and the ability to obtain sufficient sleep is impacted by a range of factors that change with maturation. This article describes normal sleep across childhood and adolescence and discusses some of the most common barriers to adequate sleep, including early school start times, technology use, and changes to circadian rhythms, and sleep homeostasis across puberty.

When Night Falls Fast: Sleep and Suicidal Behavior Among Adolescents and Young Adults

Sleep disturbances have been linked to suicidal ideation and behaviors in adolescents. Specifically, insomnia and nightmares are associated with current suicide risk and predict future ideation. Associations between hypersomnia, sleep apnea, and suicide remain inconclusive. Potential biological mechanisms underlying these relationships include executive functioning deficits and hyperarousal. Related psychological factors may include thwarted belongingness, perceived burdensomeness, and negative appraisals. Assessing suicide risk in patients with sleep disturbances, and vice versa, is needed. Therapeutic interventions such as cognitive behavior therapy for insomnia and imagery rehearsal treatment, as well as pharmacologic treatments, show promise in treating sleep disorders and suicidal behavior.

Confidence interval-based sample size determination formulas and some mathematical properties for hierarchical data

The use of hierarchical data (also called multilevel data or clustered data) is common in behavioural and psychological research when data of lower-level units (e.g., students, clients, repeated measures) are nested within clusters or higher-level units (e.g., classes, hospitals, individuals). Over the past 25 years we have seen great advances in methods for computing the sample sizes needed to obtain the desired statistical properties for such data in experimental evaluations. The present research provides closed-form and iterative formulas for sample size determination that can be used to ensure the desired width of confidence intervals for hierarchical data. Formulas are provided for a four-level hierarchical linear model that assumes slope variances and inclusion of covariates under both balanced and unbalanced designs. In addition, we address several mathematical properties relating to sample size determination for hierarchical data via the standard errors of experimental effect estimates. These include the relative impact of several indices (e.g., random intercept or slope variance at each level) on standard errors, asymptotic standard errors, minimum required values at the highest level, and generalized expressions of standard errors for designs with any-level randomization under any number of levels. In particular, information on the minimum required values will help researchers to minimize the risk of conducting experiments that are statistically unlikely to show the presence of an experimental effect.

Adolescents' sleep quality in relation to peer, family and school factors: findings from the 2017/2018 HBSC study in Flanders

PURPOSE

While a multitude of studies focused on biological and behavioral determinants of adolescents' sleep quality, a paucity of research examined the impact of social factors. The current study therefore examines the relationship between adolescents' sleep quality and peer, family and school factors.

METHODS

Data of Flemish participants in the 2017/2018 Health Behavior in School-aged Children survey (HBSC) were used, which is representative of the adolescent population (11-18 years) in Flanders. Adolescents' sleep quality was linked to individual-level data on peer relationships (i.e., peer support), family relationships (i.e., family support, perceived family wealth, caregiving responsibilities) and school relationships (i.e., teacher support, school support, school pressure) and contextual-level data on the school culture. Three-level multilevel models were fitted to account for the clustering of individuals (N = 8153) within classes (N = 769) and classes within schools (N = 177).

RESULTS

The individual-level results indicated that adolescents' sleep quality was positively related to family support, teacher support, student support and perceived family wealth. In contrast, adolescents' sleep quality was negatively related to caregiving responsibilities and school pressure. In addition, the contextual-level results pointed out that adolescents tended to report better sleep quality in less-demanding schools.

CONCLUSION

These findings highlight the need to consider social factors in promoting better sleep in adolescence.

The Value of Twins for Health and Medical Research: A Third of a Century of Progress

In 1984, Hrubec and Robinette published what was arguably the first review of the role of twins in medical research. The authors acknowledged a growing distinction between two categories of twin studies: those aimed at assessing genetic contributions to disease and those aimed at assessing environmental contributions while controlling for genetic variation. They concluded with a brief section on recently founded twin registries that had begun to provide unprecedented access to twins for medical research. Here we offer an overview of the twin research that, in our estimation, best represents the field has progress since 1984. We start by summarizing what we know about twinning. We then focus on the value of twin study designs to differentiate between genetic and environmental influences on health and on emerging applications of twins in multiple areas of medical research. We finish by describing how twin registries and networks are accelerating twin research worldwide.

Poor Sleep Associates With Recent Nonsuicidal Self-Injury Engagement in Adolescents

Objective/Background: Poor sleep has been shown to have multiple negative outcomes during adolescence, in both academic and mental health domains. Several studies have identified the association between poor sleep and suicide risk in adolescents. However, onset of and engagement in nonsuicidal self-injury (NSSI) is also common in this age group, but this behavior has rarely been studied in association with sleep in adolescent samples. In the current study, it was expected that poorer sleep and more symptoms of insomnia would associate with a greater likelihood of recent NSSI engagement and greater NSSI severity. Participants: Data were collected from 387 community adolescents (mean age = 14.19, SD = 1.08), 9% of whom reported NSSI in the past 6 months. The gender breakdown was about even (52% female) and the majority of the sample was White (88.5%). Methods: Adolescent participants were recruited from middle and high schools for a study on mental health and risk behaviors. Researchers visited schools and administered self-report questionnaires to students in large groups. Measures assessed NSSI engagement and severity features, overall sleep quality, and insomnia symptoms. Results: Results indicated that greater insomnia symptoms, but not overall sleep quality, were significantly associated with greater likelihood of recent NSSI engagement. Sleep variables were not significantly associated with NSSI severity among adolescents with recent NSSI. Conclusions: Insomnia symptoms seem to be associated with recent engagement in NSSI. Adolescents who report symptoms of insomnia should also be assessed for self-harm behavior.

Association of socioeconomic and lifestyle-related risk factors with mental health conditions: a cross-sectional study

Background

There is rising public concern over the widening health inequalities in many countries. The aim of this study was to clarify the associations of socioeconomic status (SES)-related variables, such as levels of household disposable income and employment status, and lifestyle factors with mental health conditions among Japanese adults aged 40 to 69.

Methods

A cross-sectional study of 3085 participants (1527 males and 1558 females) was undertaken by using a self-administered questionnaire that included the Japanese version of the 12-item General Health Questionnaire (GHQ-12) and questions related to socioeconomic and lifestyle factors.

Results

The prevalence of poor mental health conditions, represented by a GHQ-12 score of 4 or more, was 33.4% among males and 40.4% among females. Males whose annual household disposable income was less than 2 million yen had significantly higher GHQ-12 scores than those with an annual household disposable income above 2 million yen. As per binary logistic regression analyses, short sleep duration and the absence of physical exercise were significantly related to poor mental health conditions among both males and females. Among females, a household disposable income of less than 2 million yen could be a risk factor for poor mental health conditions. Age and habitual drinking were inversely associated with poor mental health conditions.

Conclusions

Low levels of household disposable income and unhealthy lifestyle factors were significantly associated with mental health conditions. These results suggest the importance of improving unhealthy lifestyle behaviours and developing effective health promotion programmes. In addition, there is a need for social security systems for people from different socioeconomic backgrounds.

The Relationship between Sleep Habits and Mental Health in Iranian Elementary School Children

Objectives

Sleep is one of the basic elements which affects the growth and development and mental health of the child. The aim of this study was to determine the relationship between sleep habits and mental health in elementary school children in Nahavand/Iran.

Methods

In this correlation study, 240 children aged 6-11 years old were selected by cluster random sampling from schools of Nahavand city in Iran, 2017. Data were collected through questionnaires included demographic information, children’s sleep habits (CSHQ) and children sickness indications (CSI-4). Questionnaires were completed by one of parents as self-report. The data were analyzed using Pearson’s correlation and regression analysis.

Results

Based on results, Trouble in sleeping was reported by 36% and mental health disorders by 24.5% of elementary schools children. The regression analysis showed sleep habits had significant associations with the mental health score. In other words, improper sleep habits were associated with higher scores of illness symptoms of mental health that are indicative of poor mental health.

Discussion

Sleep disorder is one of the problems of elementary schools children, which related to their mental health. Sleep health training for parents and trainers in schools can help to improve the mental health of children by reforming proper sleep habits.

Interactive effect of sleep duration and physical activity on anxiety/depression in adolescents

Although effects of sleep duration and physical activity (PA) have been demonstrated on mental health in adolescents, their interactive effect has not been studied. This cross-sectional study first examines this interactive effect on anxiety/depression in adolescents. A total of 983 Japanese students aged 12-17 were studied, using a self-report questionnaire. The interaction of sleep duration and amount of PA and their main effects on anxiety/depression, assessed using the 12-item General Health Questionnaire (GHQ-12), were investigated employing multiple regression, adjusting for grade and sex. Sleep duration and amount of PA were classified as being adequate or not, according to the duration and amount recommended by the National Sleep Foundation and World Health Organization, respectively. As a result, the interaction between sleep duration and amount of PA and their main effects were statistically significant. GHQ-12 score was significantly better in adolescents with either adequate sleep or adequate PA, not both, than those with neither adequate sleep nor adequate PA. The score, however, seemed no further improved in those with both adequate sleep and PA. The present study suggests that effects of sleep and PA on mental health need to be studied with consideration to their interaction.

Sleep patterns and their association with depression and behavior problems among Chinese adolescents in different grades

We aimed to examine sleep patterns and their association with depression and behavior problems among Chinese adolescents in different grades. A cross-sectional study was conducted in 10 cities of mainland China. A total of 8,998 Chinese adolescents (49.3% males) aged 9-20 years completed a self-administered questionnaire that included questions on sleep patterns, depressive symptoms, behavior problems, and demographic characteristics. The percentage of adolescents who slept less than 7 hr on weekdays increased with grade, while the percentage of adolescents who slept less than 7 hr on weekends remained the same. The gap in sleep length between weekdays and weekends increased from 0.6 hr in grade 5 to 2.3 hr in Grade 12. The regression analysis showed that poor sleep habits were linked to greater emotional and behavioral problems. The associations of sleep length with those problems differed by symptom and grade. Sleeping less related to depression in all grades. More behavior problems were observed in primary school students who had less sleep and in senior high school students who had more sleep than their peers. The preference for going to bed late stably related to both adolescent depression and behavior problems in all grades, although it posed a greater risk for students in higher grades.

The association between changes in depression/anxiety and trajectories of psychotic-like experiences over a year in adolescence

BACKGROUND

Recent cross-sectional studies suggest that psychotic-like experiences (PLEs) are associated with depression and anxiety in adolescents. While longitudinal studies have observed that adolescents suffer more severe symptoms of depression/anxiety when PLEs persist, it remains unclear whether depression/anxiety worsens or improves with PLE emergence or remission, respectively. In this prospective school-based study, we investigated the association between longitudinal changes in depression/anxiety and one-year PLE trajectories in adolescence.

METHODS

Nine hundred and twelve adolescents participated in the baseline assessment of PLEs and depression/anxiety; 887 (97.3%) adolescents completed the follow-up assessment one year later. Multilevel analysis was conducted to evaluate the change in depression/anxiety, evaluated using the General Health Questionnaire-12 (GHQ-12), during the year according to PLE trajectory, adjusting for baseline depression/anxiety, gender, age, substance use and victimization.

RESULTS

Sixteen percent of adolescents reported PLEs at baseline, with 56% of them remitting at follow-up. At follow-up, PLEs were experienced by 6.6% of adolescents not experiencing PLEs at baseline (incident PLE group). After adjusting for covariates, GHQ-12 score worsened significantly during the year in students with incident trajectories (regression coefficient for time, α₁=1.91, 95% CI: 1.04-2.77), but in those showing remission, GHQ-12 score did not significantly improve (α₁=-0.20, 95% CI: -0.97-0.56).

CONCLUSIONS

Greater awareness about PLEs and their trajectories in school health care settings may be a key towards the prevention and treatment of adolescent depression and anxiety.

The Relationship between Sleep Time and Mental Health Problems According to the Strengths and Difficulties Questionnaire in Children after an Earthquake Disaster: The Fukushima Health Management Survey

A cross-sectional study was performed on the adverse effects of sleep time on the mental health of children after the Great East Japan Earthquake and subsequent nuclear reactor accident in March 2011. The target participants were children aged 4–15 years living inside the government-designated evacuation zone as of 11 March 2011 (n = 29,585). The participants’ parents/guardians completed the Strengths and Difficulties Questionnaire (SDQ) and sleep time data were obtained from the 2011 Fukushima Health Management Survey. A total of 18,745 valid responses were returned. We excluded questionnaires with incomplete answers leaving 13,272 responses for the final analysis. First, we divided the children into three age groups for analysis. Second, we divided each age group into four or five groups based on sleep time per day. We used SDQ scores ≥16 to indicate a high risk of mental health problems. In the 4–6-year-old group, those with a sleep time of <9 h had a higher risk. In the 7–12-year-old group, those with ≥10 h of sleep time had a higher risk. In the 13–15-year-old group, those with ≥9 h of sleep time had a higher risk. Shorter sleep time was associated with a higher risk of mental health in 4–6-year-olds. On the other hand, oversleeping was associated with a high risk of mental health in 7–15-year-olds.

Diet quality, dietary patterns and short sleep duration: a cross-sectional population-based study

OBJECTIVE

To examine the cross-sectional association between habitual diet quality, dietary patterns and sleep duration.

METHODS

A cross-sectional study of 838 men and 1065 women participating in a large, population-based cohort study, the Geelong Osteoporosis Study. A diet quality score (DQS) was derived from answers to a food-frequency questionnaire, and a factor analysis identified habitual dietary patterns. Self-reported sleep duration was dichotomized into 'short sleep duration' (< 7 h/night) and 'adequate sleep duration' (≥ 7 h/night). Sleep duration was also grouped into predetermined cut-off ranges (< 5, 5.01-6, 6.01-7, 7.01-8, 8.01-9, 9.01-10 and ≥ 10.01 h /night) to explore the relationship between sleep duration, DQS and dietary patterns.

RESULTS

363 (34.0%) women and 339 (36.1%) men were identified with short sleep duration. After adjustments for age, socioeconomic status, education, physical activity and body mass index, each standard deviation increase in the factor score for traditional dietary pattern was associated with a 13% reduced odds for short sleep duration in men. In women, each standard deviation increase in DQS score was associated with a 21% reduced odds for short sleep duration. In women, adequate sleep was related to higher modern dietary pattern scores when compared both with excessive sleep duration (> 9 h) and shorter sleep duration (< 7 h).

CONCLUSION

Diet quality score was associated with adequate sleep duration (≥ 7 h) and reduced odds for short sleep duration (< 7 h) in Australian women.

Sleep Habits, Sleep Problems, Sleep Hygiene, and Their Associations With Mental Health Problems Among Adolescents

BACKGROUND

Studies in adults suggested that sleep could be a significant contributor to mental health. However, little is known about their relationship in adolescents.

OBJECTIVE

The present study aimed to examine the overall associations of full-spectrum sleep behaviors, including sleep habits, sleep problems, and sleep hygiene, with mental health problems among adolescents in Shanghai, China.

DESIGN

A stratified, cluster random sample of 4,823 adolescents aged 11 to 20 years participated in a cross-sectional survey. The Adolescent Sleep Disturbance Questionnaire and the modified Adolescent Sleep Hygiene Scale were used to examine sleep behaviors. The Strengths and Difficulties Questionnaire was used to evaluate mental health problems.

RESULTS

Five sleep variables were found to be associated with adolescents' mental health. The five factors covered three sleep domains: sleep habits (later bedtime during weekdays), sleep problems (maintaining sleep difficulties, disorders of arousal), and sleep hygiene (poor emotion at bedtime, unstable sleep schedule).

CONCLUSIONS

The clinical significance of the findings lies in the emphasis of comprehensive screening of sleep in the predicting, diagnosis, nursing, and intervention of adolescents' mental health problems.

Insomnia partially mediated the association between problematic Internet use and depression among secondary school students in China

Background and aims This study aims to examine the mediating effects of insomnia on the associations between problematic Internet use, including Internet addiction (IA) and online social networking addiction (OSNA), and depression among adolescents. Methods A total of 1,015 secondary school students from Guangzhou in China participated in a cross-sectional survey. Levels of depression, insomnia, IA, and OSNA were assessed using the Center for Epidemiological Studies-Depression Scale, Pittsburgh Sleep Quality Index, Young's Diagnostic Questionnaire, and Online Social Networking Addiction Scale, respectively. Logistic regression models were fit to test the associations between IA, OSNA, insomnia, and depression. The mediation effects of insomnia were tested using Baron and Kenny's strategy. Results The prevalence of depression at moderate level or above (CES-D ≥ 21), insomnia, IA, and OSNA were 23.5%, 37.2%, 8.1%, and 25.5%, respectively. IA and OSNA were significantly associated with depression (IA: AOR = 2.79, 95% CI: 1.71, 4.55; OSNA: AOR = 3.27, 95% CI: 2.33, 4.59) and insomnia (IA: AOR = 2.83, 95% CI: 1.72, 4.65; OSNA: AOR = 2.19, 95% CI: 1.61, 2.96), after adjusting for significant background factors. Furthermore, insomnia partially mediated 60.6% of the effect of IA on depression (Sobel Z = 3.562, p < .002) and 44.8% of the effect of OSNA on depression (Sobel Z = 3.919, p < .001), respectively. Discussion The high prevalence of IA and OSNA may be associated with increased risk of developing depression among adolescents, both through direct and indirect effects (via insomnia). Findings from this study indicated that it may be effective to develop and implement interventions that jointly consider the problematic Internet use, insomnia, and depression.

Daily Time-Use Patterns and Obesity and Mental Health among Primary School Students in Shanghai: A Population-Based Cross-Sectional Study

Physical activity, screen viewing, sleep, and homework among children have been independently linked to health outcomes. However, few studies have assessed the independent associations between time spent in daily activities and children's physical and mental health. This study describes time spent in four activities among primary school students in Shanghai, and examines the relationship between daily time-use patterns and obesity and mental health. The representative sample consists of 17,318 children aged 6-11 years in Shanghai. Time spent in moderate to vigorous physical activities (MVPA), screen viewing, sleep, and homework was measured by validated questionnaires. Logistic regressions were performed. We also fitted generalized additive models (GAM) and performed two-objective optimization to minimize the probability of poor mental health and obesity. In 2014, 33.7% of children spent ˂1 hour/day on MVPA, 15.6% spent ≥ 2 hours/day on screen viewing, 12.4% spent ˂ 9 hours/day on sleep, and 27.2% spent ≥ 2 hours/day on homework. The optimization results suggest that considering the 24-hour time limit, children face trade-offs when allocating time. A priority should be given to the duration of sleep and MVPA. Screen exposure should be minimized to save more time for sleep and other beneficial activities.

The Associations among Psychological Distress, Coping Style, and Health Habits in Japanese Nursing Students: A Cross-Sectional Study

Background: Nursing students in many countries have been reported to experience high levels of stress and psychological distress. Health habits could potentially mediate the association between coping styles and psychological status. The purpose of this study was to evaluate the mediation effect of health habits in the relationship between stress coping styles and psychological distress in Japanese nursing students. Methods: A total of 181 nursing students completed anonymous self-reported questionnaires comprised of the General Health Questionnaire-12 (GHQ-12), the Brief Coping Orientation questionnaire, and an additional questionnaire on health behavior. A mediation analysis using path analysis with bootstrapping was used for data analysis. Results: Multivariate linear regression analysis showed that psychological distress was significantly and positively associated with “Avoidance coping” (β = 0.39, p < 0.001), and was negatively associated with “Active coping” (β = −0.30, p < 0.001), “exercise habit” (β = −0.25, p = 0.001), and “sleeping” (β = −0.24, p = 0.002). In the path model, “Active coping” and “Avoidance coping” had significant or marginally significant associations with “exercise habits” (active: β = 0.19, p = 0.008, avoidance: β = −0.12, p = 0.088), and psychological distress (active: β = −0.25, p < 0.001, avoidance: β = 0.363, p < 0.001). However, these coping style variables did not have a significant association with “sleep”. In general, the size of the correlations was below 0.4. Conclusions: Exercise habits mediated the relationship between coping styles and psychological distress to a greater extent than sleep. The present study suggests the possibility that complex interactions between health habits and coping styles may influence the psychological status of nursing students.

Suicidality in sleep disorders: prevalence, impact, and management strategies

Sleep disturbances are associated with suicide-related thoughts and behaviors, and the incidence of sleep concerns and suicide has increased recently in the US. Most published research exploring the sleep-suicidality relation is focused on select sleep disorders, with few reviews offering a comprehensive overview of the sleep-suicidality literature. This narrative review broadly investigates the growing research literature on sleep disorders and suicidality, noting the prevalence of suicide ideation and nonfatal and fatal suicide attempts, the impact of several sleep disorders on suicide risk, and potential sleep-disorder management strategies for mitigating suicide risk. Aside from insomnia symptoms and nightmares, there exist opportunities to learn more about suicide risk across many sleep conditions, including whether sleep disorders are associated with suicide risk independently of other psychiatric conditions or symptoms. Generally, there is a lack of randomized controlled trials examining the modification of suicide risk via evidence-based sleep interventions for individuals with sleep disorders.

Japanese Sleep Questionnaire for Elementary Schoolers (JSQ-ES): validation and population-based score distribution

OBJECTIVE

The Japanese Sleep Questionnaire for Elementary Schoolers (JSQ-ES) was developed to measure the sleep habits and disturbances of Japanese children. The current study aimed to present psychometric properties and describe the score distribution of the JSQ-ES. In addition, it examined correlations between the sleep and daytime behavior of school-aged children.

METHOD

Guardians of 4369 elementary school children and 100 children diagnosed with sleep disorders in two clinics completed the JSQ-ES.

RESULTS

Exploratory factor analysis and confirmatory factor analysis suggested a nine-factor structure. The JSQ-ES internal consistency was 0.876 and 0.907 for the community and clinical groups, respectively. Score distribution differences were observed between the two groups. A cut-off point of 80 was identified for the total JSQ-ES score.

CONCLUSIONS

Exploratory factor analysis and confirmatory factor analysis suggested a nine-factor structure: (1) restless legs syndrome; (2) sleep-disordered breathing; (3) morning symptoms; (4) nighttime awakenings; (5) insomnia; (6) excessive daytime sleepiness; (7) daytime behavior; (8) sleep habits; and (9) irregular/delayed sleep phase. The study verified that the JSQ-ES is a valid and reliable instrument with which to evaluate Japanese sleep habits using a large population-based sample. The JSQ-ES may be useful in both clinical and academic settings.

Poor sleep quality and nightmares are associated with non-suicidal self-injury in adolescents

Non-suicidal self-injury (NSSI) is prevalent and is associated with increased risk of suicidal behavior in adolescents. This study examined which sleep variables are associated with NSSI, independently from demographics and mental health problems in Chinese adolescents. Participants consisted of 2090 students sampled from three high schools in Shandong, China and had a mean age of 15.49 years. Participants completed a sleep and health questionnaire to report their demographic and family information, sleep duration and sleep problems, impulsiveness, hopelessness, internalizing and externalizing problems, and NSSI. A series of regression analyses were conducted to examine the associations between sleep variables and NSSI. Of the sample, 12.6 % reported having ever engaged in NSSI and 8.8 % engaged during the last year. Univariate logistic analyses demonstrated that multiple sleep variables including short sleep duration, insomnia symptoms, poor sleep quality, sleep insufficiency, unrefreshed sleep, sleep dissatisfaction, daytime sleepiness, fatigue, snoring, and nightmares were associated with increased risk of NSSI. After adjusting for demographic and mental health variables, NSSI was significantly associated with sleeping <6 h per night, poor sleep quality, sleep dissatisfaction, daytime sleepiness, and frequent nightmares. Stepwise logistic regression model demonstrated that poor sleep quality (OR = 2.18, 95 % CI = 1.37-3.47) and frequent nightmares (OR = 2.88, 95 % CI = 1.45-5.70) were significantly independently associated with NSSI. In conclusion, while multiple sleep variables are associated with NSSI, poor sleep quality and frequent nightmares are independent risk factors of NSSI. These findings may have important implications for further research of sleep self-harm mechanisms and early detection and prevention of NSSI in adolescents.

Effects of Sleep Quality on the Association between Problematic Mobile Phone Use and Mental Health Symptoms in Chinese College Students

Problematic mobile phone use (PMPU) is a risk factor for both adolescents’ sleep quality and mental health. It is important to examine the potential negative health effects of PMPU exposure. This study aims to evaluate PMPU and its association with mental health in Chinese college students. Furthermore, we investigated how sleep quality influences this association. In 2013, we collected data regarding participants’ PMPU, sleep quality, and mental health (psychopathological symptoms, anxiety, and depressive symptoms) by standardized questionnaires in 4747 college students. Multivariate logistic regression analysis was applied to assess independent effects and interactions of PMPU and sleep quality with mental health. PMPU and poor sleep quality were observed in 28.2% and 9.8% of participants, respectively. Adjusted logistic regression models suggested independent associations of PMPU and sleep quality with mental health (p < 0.001). Further regression analyses suggested a significant interaction between these measures (p < 0.001). The study highlights that poor sleep quality may play a more significant role in increasing the risk of mental health problems in students with PMPU than in those without PMPU.

Sleep disturbances in adolescents with ADHD: A systematic review and framework for future research

BACKGROUND

Biological mechanisms underlying symptom and prognostic heterogeneity in Attention-Deficit/Hyperactivity Disorder (ADHD) are unclear. Sleep impacts neurocognition and daytime functioning and is disrupted in ADHD, yet little is known about sleep in ADHD during adolescence, a period characterized by alterations in sleep, brain structure, and environmental demands as well as diverging ADHD trajectories.

METHODS

A systematic review identified studies published prior to August 2016 assessing sleep in adolescents (aged 10-19years) with ADHD or participating in population-based studies measuring ADHD symptoms.

RESULTS

Twenty-five studies were identified (19 subjective report, 6 using actigraphy/polysomnography). Findings are mixed but overall suggest associations between sleep disturbances and 1) ADHD symptoms in the population and 2) poorer clinical, neurocognitive, and functional outcomes among adolescents with ADHD. Common limitations of studies included small or non-representative samples, non-standardized sleep measures, and cross-sectional methodology.

CONCLUSIONS

Current data on sleep in adolescent ADHD are sparse and limited by methodological concerns. Future studies are critical for clarifying a potential role of sleep in contributing to heterogeneity of ADHD presentation and prognosis. Potential mechanisms by which sleep disturbances during adolescence may contribute to worsened symptom severity and persistence of ADHD into adulthood and an agenda to guide future research are discussed.

Sleep Duration Associated with the Lowest Risk of Depression/Anxiety in Adolescents

STUDY OBJECTIVES

To investigate sleep duration associated with the least depression/anxiety in adolescence.

METHODS

Grades 7-12 Japanese students (n = 18,250, aged 12-18 y) from public junior high/high schools were studied in a cross-sectional design. Due to missing/implausible data, 15,637 out of the 18,250 students were statistically analyzed. Relationship between sleep duration on school nights and depression/anxiety, measured using self-report questionnaires, including the General Health Questionnaire-12 (GHQ-12), were studied by sex and grade, controlling for bedtime regularity.

RESULTS

When sleep duration was classified by 1-h intervals, rate of adolescents with a GHQ-12 score ≥ 4 was the lowest in males and females who slept 8.5-9.5 h and 7.5-8.5 h, respectively, (designated "references") in both grades 7-9 and 10-12. The rate was significantly higher than the references in both males and females who slept < 7.5 h, regardless of grade (P < 0.05, logistic regression). GHQ-12 tended to be worse in adolescents (2.0%-13.5%) who slept longer than the references. Sleep duration for the minimum GHQ-12 score was estimated to be 8.8 and 8.5 h in males, and 8.0 and 7.5 h in females, in grades 7-9 and 10-12, respectively, using the General Additive Model.

CONCLUSIONS

Sleep duration of ≥ 8.5 h on school nights may be associated with the lowest risk of depression/anxiety on average in male adolescents. Although the duration was estimated to be shorter in females (≥ 7.5 h) than males, this should be interpreted carefully. Most adolescents may currently be sleeping less than the optimal duration.

COMMENTARY

A commentary on this article appears in this issue on page 1491.

Nocturnal Wakefulness Is Associated With Next-Day Suicidal Ideation in Major Depressive Disorder and Bipolar Disorder

OBJECTIVE

Self-reported sleep disturbances may confer elevated risk for suicidal ideation, suicide attempts, and death. However, limited research has evaluated polysomnographically determined sleep disturbance as an acute physiologic risk factor for suicidal thoughts. This study sought to investigate the relationship between nocturnal wakefulness in association with next-day suicidal ideation using overnight polysomnography assessment from data collected between 2006 and 2013.

METHODS

Sixty-five participants with DSM-IV-diagnosed major depressive disorder or bipolar depression underwent overnight polysomnography monitoring in a sleep laboratory. The Hamilton Depression Rating Scale (HDRS) was administered the morning after polysomnography recording to assess next-day suicidal ideation, severity of depressive symptoms, and subjective sleep disturbances.

RESULTS

Using a generalized linear mixed model, a significant time-by-ideation interaction was found indicating greater nocturnal wakefulness at 4:00 am among participants with suicidal ideation (F4,136 = 3.65, P = .007). Increased time awake during the 4:00 am hour (4:00 to 4:59) was significantly associated with elevated suicidal thoughts the next day (standardized β = 0.31, P = .008). This relationship persisted after controlling for age, gender, diagnosis, and severity of depressive symptoms.

CONCLUSIONS

Greater nocturnal wakefulness, particularly in the early morning hours, was significantly associated with next-day suicidal thoughts. Polysomnographically documented sleep disruption at specific times of night may represent an acute risk factor of suicidal ideation that warrants additional research.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00024635.

Sleep in adolescent depression: physiological perspectives

Depression and disturbed sleep are intimately and bidirectionally related. During adolescence, the incidence of both insomnia and major depression increases simultaneously, in a gender-specific manner. The majority of depressed adolescents suffer from different types of subjective sleep complaints. Despite these complaints, the results from polysomnographic studies in depressed adolescents remain inconsistent. In general, similar features to those seen among adults with depressive disorder (e.g. abnormalities in rapid eye movement sleep and difficulties in sleep onset) have been reported, but expressed to a lesser degree. The inconsistency in findings may be linked with maturational factors, factors related to the stage of illness and greater heterogeneity in the clinical spectrum of depression among adolescents. The exact neurobiological mechanisms by which sleep alterations and depression are linked during adolescence are not fully understood. Aberrations in brain maturation, expressed at different levels of organization, for example gene expression, neurotransmitter and hormone metabolism, and activity of neuronal networks have been suggested. The circadian systems may change in adolescent depression beyond that observed during healthy adolescent development (i.e. beyond the typical circadian shift towards eveningness). A number of therapeutic approaches to alleviate sleep disruption associated with depression have been proposed, but research on the efficacy of these interventions in adolescents is lacking. Knowledge of the neurobiological links between sleep and depression during adolescence could lead to new insights into effective prevention and treatment of depression.

Low physical activity and high screen time can increase the risks of mental health problems and poor sleep quality among Chinese college students

OBJECTIVE

To test the independent and interactive associations of physical activity (PA) and screen time (ST) with self-reported mental health and sleep quality among Chinese college students.

METHOD

Data were collected in October, 2013. The gender, age, residential background, body mass index (BMI), perceived family economy and perceived study burden were obtained from a total of 4747 college students (41.6% males and 58.4% females). The outcomes were self-reported PA status, ST, anxiety, depression, psychopathological symptoms and sleep quality. Analyses were conducted with logistic regression models.

RESULTS

Overall, 16.3%, 15.9% and 17.3% of the students had psychological problems, such as anxiety, depression and psychopathological symptoms, respectively. The prevalence of poor sleep quality was 9.8%. High ST was significantly positively associated with anxiety (OR=1.38, 95%CI: 1.15-1.65), depression (OR=1.76, 95%CI: 1.47-2.09), psychopathological symptoms (OR=1.69, 95%CI: 1.43-2.01) and poor sleep quality (OR=1.32, 95%CI: 1.06-1.65). High PA was insignificantly negatively associated with anxiety, depression, psychopathological symptoms and poor sleep. Low PA and high ST were independently and interactively associated with increased risks of mental health problems and poor sleep quality (p<0.05 for all).

CONCLUSION

Interventions are needed to reduce ST and increase PA in the lifestyles of young people. Future research should develop and measure the impacts of interventions and their potential consequences on sleep, health, and well being.

Chronically restricted or disrupted sleep as a causal factor in the development of depression

Sleep problems are a common complaint in the majority of people suffering from depression. While sleep complaints were traditionally seen as a symptom of mood disorders, accumulating evidence suggests that in many cases the relationship may be reverse as well. A long list of longitudinal studies shows that sleep complaints often precede the onset of depression and constitute an independent risk factor for the development of the disorder. Additionally, experimental studies in animals show that chronically restricted or disrupted sleep may gradually induce neurobiological changes that are very similar to what has been reported for depressed patients. The mechanisms through which insufficient sleep increases the risk for depression are poorly understood but may include effects of sleep disturbance on neuroendocrine stress systems, serotonergic neurotransmission, and various interacting signaling pathways involved in the regulation of neuronal plasticity and neurogenesis. Because sleep is considered to play a crucial role in regulating neuronal plasticity and synaptic strength, chronically insufficient sleep may contribute to depression through an impairment of these plasticity processes leading to altered connectivity and communication within and between brain regions involved in the regulation of mood.

Sleep characteristics, chronotype and winter depression in 10-20-year-olds in northern European Russia

The purpose of this work was to examine the relationships between geographical coordinates and the prevalence of winter depression (SADW ), and to compare the sleep characteristics and chronotype of youths with and without SADW . We conducted a cross-sectional study of self-reported sleep characteristics, chronotype and winter depression in northern European Russia. Two questionnaires, the Munich Chronotype Questionnaire (MCTQ) and the Seasonal Pattern Assessment Questionnaire (SPAQ), were administered to a total of 3435 adolescents aged 10-20 years (1517 males and 1918 females). The prevalence of SADW in the study population was 8.4% and sub-SADW 11.8%. Four variables predicted the likelihood of SADW in youths: sex [higher in females: odds ratio (OR): 1.87, P < 0.0001], age (increases with age: OR: 1.09, P < 0.001), latitude (higher in the North: OR: 1.49, P < 0.029) and position in the time zone (higher in the West: OR: 1.61, P < 0.001). Later sleeping and waking, longer sleep latencies, more severe sleep inertia, shorter total sleep times and lower sleep efficiencies were observed in both males and females with SADW . The influence of SADW on sleep characteristics was more pronounced on school days. Significant phase delays of the sleep-wake rhythm and severe social jetlag (the difference between the mid-point of sleep phase at weekends and on workdays) were observed in females with SADW , but not in males. There are significant differences in sleep characteristics and chronotype between people with SADW and no-SAD. We demonstrate that both latitude of residence and location within the time zone are significant predictors of SADW in young inhabitants of the North.

Sleep in infancy and childhood: implications for emotional and behavioral difficulties in adolescence and beyond

PURPOSE OF REVIEW

Extensive scientific efforts have been made in an attempt to identify early markers of behavioral and emotional problems. In this context, sleep has received considerable research attention, as it appears to be closely linked to developmental psychopathology. The present review synthesizes some of the most recent findings regarding the concurrent and longitudinal associations between psychopathology and behavioral manifestations of sleep in childhood and adolescence.

RECENT FINDINGS

Recent evidence suggests that compromised sleep is associated with both internalizing and externalizing problems in childhood and adolescence. Moreover, sleep problems have been shown to predict the development of various emotional and behavioral problems, including depression, anxiety, attention-deficit hyperactivity disorder, risk-taking and aggression. Yet, inconsistencies are apparent, particularly among findings that are based on objective sleep measurement.

SUMMARY

Taken together, most recent findings suggest that poor sleep in childhood and adolescence constitutes a risk factor for psychopathological symptoms. Accordingly, the importance of early detection and intervention should be a primary goal in clinical settings. In the research domain, the underlying mechanism of these associations should receive future research attention, in an attempt to broaden the understanding of the relationship between sleep and psychopathology.