Associations between diurnal preference, sleep quality and externalizing behaviours: a behavioural genetic analysis

[Effects of Television Screen Exposure on the Mental Health of Middle-aged and Older Adults]

Objective

To explore the relationship between the duration of TV screen exposure and mental illnesses in middle-aged and older adults.

Methods

The study was based on a cohort of 500 000 participants from UK Biobank. A prospective cohort of participants with TV screen exposure was established based on the exposure factor of the participants' daily TV watching time. The outcome was defined as psychological problem-related outcomes. The follow-up period extended from the time of baseline assessment of the participants to December 31, 2019. Cox proportional hazard model was used to calculate the hazard ratio (HR) of suicide attempts and mental illnesses in the population covered by the study.

Results

A total of 410 946 participants were followed up for an average of 10.8 years and 33 071 of them experienced an outcome events. Compared with the group of participants who had 0-1 h of daily TV time, the group of participants who watched TV for more than 5 h per day had an HR of 1.37 (95% confidence interval [CI]: 1.31-1.44). In stratified analysis, we found that, compared with individuals aged 45 years and over, individuals who were 38-44 years old were at a higher risk of developing mental illness when they watched TV for long periods of time (>5 h HR 1.83, 95% CI: 1.55-2.15). Long periods of outdoor activities reduced the risk of mental illness for individuals who watched TV for long periods of time (>5 h HR 1.26, 95% CI: 1.16-1.37). Having less than 5 hours of sleep increased the mental health risks of individuals who watched TV for long periods of time (>5 h HR 1.56, 95% CI: 1.34-1.81) and when sleep duration increased, TV watching showed decreased impact on mental health risks (>5 h HR dropped from 1.56 to 1.19).

Conclusion

Our findings suggest that TV viewing for long periods of time increases the risk of mental illness. Increaseing outdoor activity time and sleep time reduces the negative impact of watching TV on mental health.

The role of anxiety and callous-unemotional traits in the relationship between externalizing behaviors and sleep problems in clinic-referred youth

In a growing body of literature, poor sleep quality has been associated with externalizing problems. In adults, anxiety was found to mediate the relationship, and callous-unemotional (CU) traits were found to moderate it. We sought to examine these relationships in a child population. We examined these relationships in 239 clinic-referred youth (age 6-17) in Singapore with externalizing behavior problems. Parent- but not child-rated sleep problems were associated with increased parent-rated externalizing problems. This association was partially mediated by anxiety. Unlike in adults, CU traits did not moderate the relationship. Sleep problems were associated with externalizing problems regardless of the level of CU traits. It is possible externalizing behaviors may lead children to internalize experiences, leading to anxiety about their behaviors. Another possibility is externalizing behaviors may lead to more stressful life experiences due to negative reactions children with externalizing behaviors receive from parents, teachers, or peers. Regardless, the partial mediation found indicates anxiety may be an important factor to consider in future interventions focused on improving sleep as a means to reduce externalizing problems.

Development of morning-eveningness in adolescence: implications for brain development and psychopathology

BACKGROUND

Morning-evening preference is defined as an individual's preference for a morning- or evening-oriented rhythm. Across adolescence, a preference for eveningness becomes more predominant. Although eveningness is cross-sectionally associated with internalizing and externalizing psychopathology, few studies have examined developmental changes in eveningness and its potential biological substrates. Here, we investigated the longitudinal relationships among the trajectory of eveningness preference, internalizing and externalizing psychopathology and white matter development, across adolescence.

METHODS

Two-hundred and nine adolescents (49% male) were assessed longitudinally at four separate time points between 12 and 19 years of age. Morning-evening preference and internalizing and externalizing symptoms were assessed at each time point. Diffusion-weighted images were acquired on a subset of participants at the final two time points to estimate changes in global mean fractional anisotropy (FA). Linear mixed models were performed to estimate the change in eveningness over time. A series of linear regression models assessed the influence of change in eveningness on psychopathology and white matter development at age 19.

RESULTS

Across the sample, a preference for eveningness became more predominant by 19 years of age. Greater individual-level change towards eveningness significantly predicted greater severity in externalizing, but not internalizing, symptoms at 19 years of age. In contrast, change in psychopathology from 12 to 19 years of age was not associated with morning-eveningness at age 19. A change towards eveningness predicted an attenuated increase in FA between 17 and 19 years of age.

CONCLUSIONS

This study suggests that developmental changes in morning-evening preference may predict both neurodevelopmental and psychological outcomes in adolescents.

Behaviour genetics and sleep: A narrative review of the last decade of quantitative and molecular genetic research in humans

During the last decade quantitative and molecular genetic research on sleep has increased considerably. New behavioural genetics techniques have marked a new era for sleep research. This paper provides a summary of the most important findings from the last ten years, on the genetic and environmental influences on sleep and sleep disorders and their associations with health-related variables (including anxiety and depression) in humans. In this review we present a brief summary of the main methods in behaviour genetic research (such as twin and genome-wide association studies). We then discuss key research findings on: genetic and environmental influences on normal sleep and sleep disorders, as well as on the association between sleep and health variables (highlighting a substantial role for genes in individual differences in sleep and their associations with other variables). We end by discussing future lines of enquiry and drawing conclusions, including those focused on problems and misconceptions associated with research of this type. In this last decade our knowledge about genetic and environmental influences on sleep and its disorders has expanded. Both, twin and genome-wide association studies show that sleep and sleep disorders are substantially influenced by genetic factors and for the very first time multiple specific genetic variants have been associated with sleep traits and disorders.

Commentary: The potential of sleep research to contribute to our understanding on antisocial behaviour - a reflection on Brown, Beardslee, Frick, Steinberg and Cauffman (2022)

A growing body of work indicates that sleep problems are associated with antisocial behaviour in young people. This opens up the opportunity for interventions that improve sleep to reduce antisocial behaviour. Brown et al. (2022) provide important new leads that can help to target interventions, highlighting that the relationship may be most relevant to aggressive offending and that it is consistent across adolescence and young adulthood. The within-individual design adopted in this study has a number of methodological strengths. This commentary evaluates the effectiveness of the approach in terms of accounting for confounding effects and addressing temporal ordering. Directions for future research to build on the target paper are considered.

Adolescent delinquent behavior and sleep deficiency: a test of multiple mechanisms using sibling comparison designs

The aim of the study was to investigate the association between adolescent delinquency and sleep deficiency. A comprehensive set of potential mechanisms underlying this association were also examined. Using data from the National Longitudinal Study of Adolescent to Adult Health, the present study employed sibling fixed effects models to account for unobservable family-level confounders, such as genetic predisposition, parenting style, parental ability, and school and neighborhood environments. In Sobel mediation tests, the following mechanism variables were explored: substance use, school-based relationships, and parent-child relationships. An increase in delinquency (measured by the total number of types of delinquent behavior engaged) was associated with an increased risk of sleep deficiency one year later. Sibling fixed effects models with a lagged dependent variable revealed that this association is robust to adjustment for family-level heterogeneity as well as prior sleep deficiency. Substance use was the most salient pathway linking delinquency to sleep deficiency (17% for binge drinking and 26% for marijuana use), followed by student-teacher relationships (17%) and father-child relationships (16%). The results of this study suggest that policymakers and practitioners may consider developing interventions to help delinquent adolescents avoid substance use and restore disruptions of student-teacher and father-child relationships.

The association of sleep quality and aggression: A systematic review and meta-analysis of observational studies

Poor sleep quality is closely related to aggression, but despite the promise of new therapeutic possibilities, a systematic synthesis of observational research on the association between sleep quality and aggression is lacking. This systematic review and meta-analysis examined the association between sleep quality and aggression, using the academic databases PubMed and PsycINFO. Subjective and objective measures of sleep quality were included, as well as multiple measures of aggression, assessing aggressive and externalizing behavior, anger, hostility and irritability. Ninety-two observational articles, containing 96 studies, encompassing a total of 58.154 children, adolescents and adults were sourced out of 7161 references identified. Methodological quality was moderate or strong in 76% of studies. Data for meta-analysis was available from 74 studies. Poorer sleep quality was associated with higher aggression in 80.8% of studies. Pooled results showed a correlation of 0.28 (95%CI 0.25-0.31; I² = 90.1%) and odds ratio of 3.61 (95%CI 1.13-11.51; I² = 88.3%). Effect estimates and heterogeneity varied according to population type and measurement instruments, but not according to article quality or age group. Our findings confirm that poor sleep quality is consistently associated with higher aggression. As most evidence is cross-sectional, more prospective and high-quality experimental evidence is required to elucidate cause-effect and optimize prevention and treatment of aggression.

Association between symptoms of sleep apnea and problem behaviors in young adult twins and siblings

BACKGROUND

Sleep apnea is one of the most common sleep disorders and it is related to multiple negative health consequences. Previous studies have shown that sleep apnea is influenced by genetic factors. However, studies have not investigated the genetic and environmental influences of symptoms of sleep apnea in young adults. Furthermore, the underpinnings of the relationship between apnea symptoms and internalizing/externalizing problems are unknown. The objectives of this study were to estimate the magnitude of: (1) genetic and environmental influences on self-reported apnea symptoms; (2) the relationship between self-reported apnea symptoms and internalizing/externalizing traits; (3) genetic and environmental influences on the associations between self-reported apnea symptoms, internalizing behaviors and externalizing behaviors.

METHODS

In a twin/sibling study, univariate and multivariate models were fitted to estimate both individual variance and sources of covariance between symptoms of sleep apnea and internalizing/externalizing behaviors.

RESULTS

Our results show that genetic influences account for 40% of the variance in sleep apnea symptoms. Moreover, there are modest associations between depression, anxiety and externalizing behaviors with apnea symptoms (ranging from r = 0.22-0.29). However, the origins of these associations differ. For example, whereas most of the covariation between symptoms of depression and sleep apnea can be explained by genes (95%), there was a larger role for the environment (53%) in the association between symptoms of anxiety and sleep apnea.

CONCLUSIONS

Genetic factors explain a significant proportion of variance in symptoms of apnea and most of the covariance with depression.

COVID-19 Pandemic on Fire: Evolved Propensities for Nocturnal Activities as a Liability Against Epidemiological Control

Humans have been using fire for hundreds of millennia, creating an ancestral expansion toward the nocturnal niche. The new adaptive challenges faced at night were recurrent enough to amplify existing psychological variation in our species. Night-time is dangerous and mysterious, so it selects for individuals with higher tendencies for paranoia, risk-taking, and sociability (because of security in numbers). During night-time, individuals are generally tired and show decreased self-control and increased impulsive behaviors. The lower visibility during night-time favors the partial concealment of identity and opens more opportunities for disinhibition of self-interested behaviors. Indeed, individuals with an evening-oriented chronotype are more paranoid, risk-taking, extraverted, impulsive, promiscuous, and have higher antisocial personality traits. However, under some circumstances, such as respiratory pandemics, the psychobehavioral traits favored by the nocturnal niche might be counter-productive, increasing contagion rates of a disease that can evade the behavioral immune system because its disease cues are often nonexistent or mild. The eveningness epidemiological liability hypothesis presented here suggests that during the COVID-19 pandemic, the evening-oriented psychobehavioral profile can have collectively harmful consequences: there is a clash of core tendencies between the nocturnal chronotype and the recent viral transmission-mitigating safety guidelines and rules. The pandemic safety protocols disrupt much normal social activity, particularly at night when making new social contacts is desired. The SARS-CoV-2 virus is contagious even in presymptomatic and asymptomatic individuals, which enables it to mostly evade our evolved contagious disease avoidance mechanisms. A growing body of research has indirectly shown that individual traits interfering with social distancing and anti-contagion measures are related to those of the nocturnal chronotype. Indeed, some of the social contexts that have been identified as superspreading events occur at night, such as in restaurants, bars, and nightclubs. Furthermore, nocturnal environmental conditions favor the survival of the SARS-CoV-2 virus much longer than daytime conditions. We compare the eveningness epidemiological liability hypothesis with other factors related to non-compliance with pandemic safety protocols, namely sex, age, and life history. Although there is not yet a direct link between the nocturnal chronotype and non-compliance with pandemic safety protocols, security measures and future empirical research should take this crucial evolutionary mismatch and adaptive metaproblem into account, and focus on how to avoid nocturnal individuals becoming superspreaders, offering secure alternatives for nocturnal social activities.

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.

Sleep duration: A review of genome-wide association studies (GWAS) in adults from 2007 to 2020

A modest body of research exists in the area of human sleep genetics, which suggests that specific sleep phenotypes are, like many other complex traits, somewhat heritable. Until 2007 research into sleep genetics relied solely on twin studies, but in the last 13 years with the advent of huge biobanks and very large-scale genome-wide association studies, the field of molecular sleep genetics has seen important advances. To date, the majority have focused on self-reported sleep duration, but in recent years genome-wide association studies of objectively-measured sleep have emerged. These genetic studies have discovered multiple common genetic variants and as such, have provided insight into potential biological pathways, causal relationships between sleep duration and important disease outcomes using Mendelian randomisation. They have also shown that the heritability of these traits may not be as high as previously estimated. This article is the first to provide a detailed review of these recent advances in the genetic epidemiology of sleep duration. Studies were identified using both the GWAS Catalog and PubMed for completeness. Focus is on the genome-wide association studies published to date, including whether and how they have elucidated important biology and advanced knowledge in the area of sleep and health.

Children's sleep, impulsivity, and anger: shared genetic etiology and implications for developmental psychopathology

BACKGROUND

Prior research has established links between poor sleep and problems in emotion regulation. Impulsivity and anger/frustration are core features of child psychopathology. Further, sleep problems are commonly associated with psychopathology. This study examined shared and unique genetic and environmental influences on sleep, impulsivity, and anger/frustration in the middle childhood period with potential ramifications for psychopathology.

METHODS

Families (29.9% monozygotic, 38.6% same-sex dizygotic, 31.5% opposite-sex dizygotic) from a longitudinal twin study participated (N = 613 twins). Twins (M_age  = 8.37, SD = 0.66; 49% female; 58% non-Latinx European American, 30% Latinx) wore actigraph watches for seven days to assess sleep. Primary caregivers (95.3% mothers) completed standardized questionnaires to assess twins' temperament (impulsivity, anger/frustration).

RESULTS

Univariate ACE twin structural equation models indicated strong genetic influences (76%) on impulsivity, whereas the largest proportion of variance in anger/frustration was attributed to the shared environment (56%). Bivariate model fitting indicated that sleep-impulsivity and sleep-anger/frustration associations in children are genetic; thus, a mutual underlying genetic factor likely contributes to the commonality in these associations.

CONCLUSIONS

Given evidence that sleep problems, impulsivity, and anger/frustration are mechanisms associated with psychopathology, our findings suggest a genetic commonality and the need to focus on shared and unique risk factors when understanding etiology. Early intervention and prevention efforts should target both sleep problems and high levels of impulsivity and anger/frustration in children, which may have implications for later psychopathology.

Later Chronotype Is Associated with Higher Alcohol Consumption and More Adverse Childhood Experiences in Young Healthy Women

This study aimed at examining potential associations of mid sleep timing (chronotype) and social jetlag with intake of alcohol and caffeine, depressive symptoms, and body mass index (BMI) in a sample of healthy young women. Furthermore, it was explored whether these behavioral sleep–wake parameters are associated with adverse childhood experiences (ACEs). In total, 146 women (21.7 ± 1.7 years) took part in a two-week assessment on daily consumption of alcohol and caffeine. They completed questionnaires on ACEs, chronotype, sleep quality and depressive symptoms. Partial correlations and Chi-Square tests were calculated to assess the relationships between the assessed variables. Results show an association on a trend level for chronotype (r = 0.162, p = 0.053) and a significant association for social jetlag (r = 0.169, p = 0.044) with average alcohol intake. Furthermore, participants with above-median ACEs were more likely to be late chronotypes compared to the below-median group (X2(2) = 6.595, p = 0.037). We could replicate the association among late chronotype, social jetlag and higher alcohol consumption in a sample of healthy, young women. Furthermore, our results suggest a relationship between ACEs and chronotype. Although it can be hypothesized that it is rather ACEs that have an impact on chronotype, further research is needed to explore this relationship more and to shed more light on the direction of the association between chronotype and ACEs as well as on underlying mechanisms and possible mediators.

Sleep Quantity and Problems as Mediators of the Eveningness-Adjustment Link during Childhood and Adolescence

Chronotype, or morningness/eveningness, has been associated with adjustment in both children and adolescents. Specifically, eveningness has been linked to adjustment difficulties; however, the mechanism underlying this association is poorly understood. The purpose of this study was to test whether the associations between eveningness and adjustment difficulties could be explained by an unfavorable impact of eveningness on sleep. Links from chronotype to internalizing problems and problem behaviors via sleep quantity and sleep problems were tested in a sample from the European Longitudinal Study of Pregnancy and Childhood (N = 3485; 48.8% female), both when the participants were children (7 years at T1, 11 at T2) and when they were adolescents (15 years at T1, 18 at T2). The findings provided evidence that eveningness predicted greater sleep problems and lower sleep quantity; however, only sleep problems predicted internalizing problems and problem behaviors. Sleep quantity did not mediate the eveningness-adjustment link, and sleep problems did so only in children. The findings show that sleep problems appear to be more important in explaining the eveningness-adjustment link rather than altered sleep quantity, commonly associated with eveningness.

Heritability of siesta and night-time sleep as continuously assessed by a circadian-related integrated measure

Siesta is a relevant aspect of sleep due to its posited relationship with health or cognitive function. However, unlike night-time sleep, studies about daytime-sleep determinants and characteristics are scarce, and the genetic/environmental structure of siesta is still unknown. Our aim was to explore the relative contribution of genetic and environmental factors to variation in sleep-wake rhythm, measured by a continuous assessment of temperature-activity-position (TAP), which allows for diurnal sleep analysis. The sample comprised 53 pairs of female twins (28 MZ and 25 DZ), selected from the Murcia Twin Register. Mean age of participants was 52 (SD: 6.03). Zygosity was determined by DNA. We conducted separate univariate analyses to study the sources of variance of daytime and night-time sleep parameters. About 60% of the sample reported to take siesta at least once a week. Heritability of taking siesta and daytime sleep duration was 65 and 61% respectively. Other sleep parameters obtained by TAP showed heritability estimates between 36 and 69%, suggesting a relevant impact of genetic factors on sleep rhythm. This is the first study to investigate the relative contribution of genetic factors to siesta. By using TAP, we introduce a novel approach to the study of diurnal sleep characteristics.

Externalizing Behaviors and Callous-Unemotional Traits: Different Associations With Sleep Quality

Study Objectives

Sleep quality is associated with different aspects of psychopathology, but relatively little research has examined links between sleep quality and externalizing behaviors or callous-unemotional traits. We examined: (1) whether an association exists between sleep quality and externalizing behaviors; (2) whether anxiety mediates this association; (3) whether callous-unemotional traits are associated with sleep quality.

Methods

Data from two studies were used. Study 1 involved 1556 participants of the G1219 study aged 18-27 years (62% female). Questionnaire measures assessed sleep quality, anxiety, externalizing behaviors, and callous-unemotional traits. Study 2 involved 338 participants aged 18-66 years (65% female). Questionnaires measured sleep quality, externalizing behaviors, and callous-unemotional traits. In order to assess objective sleep quality, actigraphic data were also recorded for a week from a subsample of study 2 participants (n = 43).

Results

In study 1, poorer sleep quality was associated with greater externalizing behaviors. This association was partially mediated by anxiety and moderated by levels of callous-unemotional traits. There was no significant relationship between sleep quality and callous-unemotional traits. In study 2, poorer sleep quality, as assessed via self-reported but not objective measures, was associated with higher levels of externalizing behaviors. Furthermore, in study 2, better sleep quality (indicated in both questionnaires and actigraphy measures: lower mean activity, and greater sleep efficiency) was associated with higher levels of callous-unemotional traits.

Conclusions

Self-reports of poorer sleep quality are associated with externalizing behaviors, and this association is partially mediated by anxiety. Callous-unemotional traits are not associated with poor sleep and may even be related to better sleep quality. This is an exceptional finding given that poor sleep quality appears to be a characteristic of most psychopathology.

Adolescent daytime sleepiness as a risk factor for adult crime

BACKGROUND

While recent cross-sectional research has documented a relationship between sleep problems and antisocial behavior, the longitudinal nature of this relationship is unknown. This study tests both the hypothesis that adolescent daytime sleepiness is associated with later adult criminal offending, and also tests a biopsychosocial mediation model in which social adversity predisposes to sleepiness, which in turn predisposes to attentional impairment, and to adult crime.

METHODS

Schoolboys aged 15 years rated themselves on self-report sleepiness. Age 15 antisocial behavior was assessed by teacher ratings and self-reports, while convictions for crime were assessed at age 29. Attentional capacity at age 15 was assessed by autonomic orienting, with arousal assessed by the electroencephalogram (EEG).

RESULTS

Sleepy adolescents were more likely to be antisocial during adolescence, and were 4.5 times more likely to commit crime by age 29. The sleepiness-adult crime relationship withstood control for adolescent antisocial behavior. Self-report sleepiness predicted to adult crime over and above objective measures of daytime sleepiness (EEG theta activity) and age 15 antisocial behavior. Poor daytime attention partly mediated the sleep-crime relationship. Mediation analyses also showed that social adversity predisposed to daytime sleepiness which was associated with reduced attention which in turn predisposed to adult crime.

CONCLUSIONS

Findings are the first to document a longitudinal association between sleepiness in adolescence and crime in adulthood. The longitudinal nature of this relationship, controlling for age 15 antisocial behavior, is consistent with the hypothesis that adolescent sleepiness predisposes to later antisociality. Findings are also consistent with the notion that the well-established link between social adversity and adult crime is partly explained by sleepiness. Results suggest that a very brief and simple assessment of subjective daytime sleepiness may have prognostic clinical value, and that interventions to reduced sleepiness could be a useful avenue for future crime prevention.

An examination of the etiologic overlap between the genetic and environmental influences on insomnia and common psychopathology

BACKGROUND

Insomnia is comorbid with internalizing and externalizing psychiatric disorders. However, the extent to which the etiologic influences on insomnia and common psychopathology overlap is unclear. There are limited genetically informed studies of insomnia and internalizing disorders and few studies of overlap exist with externalizing disorders.

METHODS

We utilized twin data from the Virginia Adult Twin Studies of Psychiatric and Substance Use Disorders (total n = 7,500). Insomnia, internalizing disorders (major depressive disorder [MDD], generalized anxiety disorder [GAD]), and alcohol abuse or dependence (AAD) were assessed at two time points, while antisocial personality disorder (ASPD) was assessed once. Cholesky decompositions were performed in OpenMx and longitudinal measurement models were run on available phenotypes to reduce measurement error.

RESULTS

The latent additive genetic influences on insomnia overlapped significantly (56% for females, 74% for males) with MDD and were shared completely (100%) with GAD. There was significant overlap of latent unique environmental influences, with overlap ranging from 38 to 100% across disorders. In contrast, there was less genetic overlap between insomnia and externalizing disorders, with 18% of insomnia's heritability shared with AAD and 23% with ASPD. Latent unique environmental overlap between insomnia and both externalizing disorders was negligible.

CONCLUSIONS

The evidence for substantial genetic overlap between insomnia and stable aspects of both internalizing disorders suggests that there may be few insomnia-specific genes and investigation into unique environmental factors is important for understanding insomnia development. The modest overlap between insomnia and externalizing disorders indicates that these disorders are genetically related, but largely etiologically distinct.

Sleep and Mental Health in Undergraduate Students with Generally Healthy Sleep Habits

Whereas previous research has indicated that sleep problems tend to co-occur with increased mental health issues in university students, relatively little is known about relations between sleep quality and mental health in university students with generally healthy sleep habits. Understanding relations between sleep and mental health in individuals with generally healthy sleep habits is important because (a) student sleep habits tend to worsen over time and (b) even time-limited experience of sleep problems may have significant implications for the onset of mental health problems. In the present research, 69 university students with generally healthy sleep habits completed questionnaires about sleep quality and mental health. Although participants did not report clinically concerning mental health issues as a group, global sleep quality was associated with mental health. Regression analyses revealed that nighttime sleep duration and the frequency of nighttime sleep disruptions were differentially related to total problems and clinically-relevant symptoms of psychological distress. These results indicate that understanding relations between sleep and mental health in university students with generally healthy sleep habits is important not only due to the large number of undergraduates who experience sleep problems and mental health issues over time but also due to the potential to intervene and improve mental health outcomes before they become clinically concerning.

Annual Research Review: Sleep problems in childhood psychiatric disorders--a review of the latest science

BACKGROUND

Hippocrates flagged the value of sleep for good health. Nonetheless, historically, researchers with an interest in developmental psychopathology have largely ignored a possible role for atypical sleep. Recently, however, there has been a surge of interest in this area, perhaps reflecting increased evidence that disturbed or insufficient sleep can result in poor functioning in numerous domains. This review outlines what is known about sleep in the psychiatric diagnoses most relevant to children and for which associations with sleep are beginning to be understood. While based on a comprehensive survey of the literature, the focus of the current review is on the latest science (largely from 2010). There is a description of both concurrent and longitudinal links as well as possible mechanisms underlying associations. Preliminary treatment research is also considered which suggests that treating sleep difficulties may result in improvements in behavioural areas beyond sleep quality.

FINDINGS

To maximise progress in this field, there now needs to be: (a) greater attention to the assessment of sleep in children; (b) sleep research on a wider range of psychiatric disorders; (c) a greater focus on and examination of mechanisms underlying associations; (d) a clearer consideration of developmental questions and (e) large-scale well-designed treatment studies.

CONCLUSIONS

While sleep problems may sometimes be missed by parents and healthcare providers; hence constituting a hidden risk for other psychopathologies - knowing about these difficulties creates unique opportunities. The current excitement in this field from experts in diverse areas including developmental psychology, clinical psychology, genetics and neuropsychology should make these opportunities a reality.

CHRONOTYPE ASSOCIATIONS WITH DEPRESSION AND ANXIETY DISORDERS IN A LARGE COHORT STUDY

BACKGROUND

The chronotype, being a morning or an evening type, can influence an individual's psychological health. Studies have shown a link between depressed mood and being an evening type; however, most studies have used symptom scales and not diagnostic criteria, and confounding factors such as sleep patterns and somatic health factors have often not been considered. This study aims to examine the association between chronotype and depressive (major depressive disorder (MDD), dysthymia) and anxiety (generalized anxiety disorder, panic disorder, agoraphobia, and social phobia) disorders diagnosed using clinical interviews, while taking into account relevant sociodemographic, clinical, somatic health, and sleep parameters.

METHODS

Data from a large cohort, the Netherlands Study of Depression and Anxiety were used (n = 1,944), which included 676 currently depressed and/or anxious patients, 831 remitted patients, and 437 healthy controls. Chronotype was assessed using the Munich Chronotype Questionnaire.

RESULTS

Our results showed that current depressive and/or anxiety disorders were associated with a late chronotype (β = .10, P = .004) even when adjusting for sociodemographic, somatic health, and sleep-related factors (β = .09, P = .03). When examining each type of disorder separately, MDD only, but not dysthymia or specific anxiety disorders, was associated with the late chronotype. The late chronotype also reported significant diurnal mood variation (worse mood in the morning).

CONCLUSIONS

Our findings show a clear association between MDD and late chronotype (being an evening type), after controlling for a range of pertinent factors. A late chronotype is therefore associated with a current status of MDD and deserves the relevant clinical attention when considering treatments.

Poor actigraphic and self-reported sleep patterns predict delinquency and daytime impairment among at-risk adolescents

OBJECTIVE

To evaluate associations between actigraphic sleep patterns, subjective sleep quality, and daytime functioning (ie, sleepiness, symptoms of depression, and delinquency and other conduct problems) in at-risk adolescents.

DESIGN

Prospective, observational cohort study.

SETTING

Providence, RI, predominantly home and school and 2 visits to the Brown Center for the Study of Children at Risk.

PARTICIPANTS

A diverse group of low-income 13-year-olds (n = 49) with and without prenatal drug exposure.

INTERVENTIONS

None.

MEASUREMENTS

Actigraphy, sleep diaries, and sleep and health questionnaires.

RESULTS

Above and beyond the effects of prenatal drug exposure and postnatal adversity, actigraphic daytime sleep was a significant predictor of daytime sleepiness and delinquency. Subjective sleep quality was a significant predictor of daytime sleepiness, delinquency, and depressive symptoms. Later bed times predicted increased delinquency.

CONCLUSIONS

There was a unique effect of actigraphic daytime sleep duration, subjective nighttime sleep quality, and bedtime on daytime functioning (ie, sleepiness, symptoms of depression, and delinquency and other conduct problems) of at-risk adolescents. In these vulnerable youth, these problematic sleep patterns may contribute to feeling and behaving poorly. Intervention studies with at-risk teens should be conducted to further explore the role of these sleep parameters on daytime functioning.

The impact of sleep duration on adolescent development: a genetically informed analysis of identical twin pairs

Recent work provides evidence that reduced sleep duration has detrimental effects on a range of developmentally related outcomes during adolescence. Yet, the potential confounding influence of genetic and shared environmental effects has not been sufficiently addressed. This study addresses this issue by analyzing cross-sectional data from the twin sub-sample of the first wave of the National Longitudinal Study of Adolescent Health [N ≈ 287 MZ (monozygotic) twin pairs; 50% male; 22% Black; mean age = 15.75]. Associations between sleep duration (measured through two different strategies, one tapping number of hours slept at night and the other measuring weeknight bedtimes) and seven outcomes (self-control, depressive symptoms, suicidal ideation, body mass index, violent delinquency, non-violent delinquency, and drug use) were estimated. Consistent with prior research, associations between sleep duration and several outcomes were statistically significant when using standard social science analytic methods. Yet, when employing a methodology that accounts for genetic and shared environmental influences, some of these associations were reduced to non-significance. Still, two consistent associations remained in that participants who reported sleeping fewer hours at night (or who reported later bedtimes) exhibited lower levels of self-control and more depressive symptoms. Implications of the findings and directions for future research are discussed.

Clinical Implications of Impaired Sleep

Despite its pervasiveness in primary care, deficient sleep often is underappreciated as a cue to other health risks. Accordingly, this review discusses contemporary evidence-based perspectives on impaired sleep and its associations with other lifestyle medicine concerns, including obesity, cardiovascular conditions, psychological problems, and health-compromising habits. The potential clinical benefits of promoting sleep health also will be considered.

Monozygotic twin differences in non-shared environmental factors associated with chronotype

Twin studies have highlighted that a large proportion of variability in chronotype is accounted for by individual-specific environmental factors (non-shared environmental influences). However, little research has aimed to identify specific non-shared environmental influences on chronotype. Although epidemiological studies have shed light on possible environmental influences on chronotype, a substantial amount of research has highlighted the importance of genetic influences on exposure toward specific environments, a process termed gene-environment correlation. It is possible that associations between the environment and chronotype are in part determined by genetics, rather than being purely environmental in origin. One way of exploring the contribution of purely non-shared environmental components on associations between chronotype and the environment is to use the monozygotic twin differences design. This design allows us to tease apart the influences of genetics and the environment to identify purely environmental components. One hundred eighty-nine monozygotic twin pairs (mean age 19.81 years, SD = 1.26, range = 18-22 years, 66.1% female) completed the Horne and Östberg Morningness-Eveningness Questionnaire as a measure of chronotype and questionnaires assessing the following candidate non-shared environmental influences: dependent and independent negative life events, educational attainment, employment status, relationship status, deviant peers, affiliation with deviant peers, general health, smoking, drug use, and alcohol use. Linear regression analyses indicated the presence of gene-environment correlation for the majority of associations between chronotype and candidate environmental influences. When controlling for genetic and shared environmental effects, within monozygotic twin-pair differences in chronotype were associated with within monozygotic twin-pair differences in dependent negative life events (β = -0.27, p < 0.001), educational attainment (β = -0.14, p < 0.05), smoking status (β = 0.22, p < 0.01), and drug use (β = -0.16, p < 0.01). These results suggest that some of the association between these variables is purely environmental in nature. The associations between the remaining environmental variables and chronotype, however, may be intertwined with underlying genetic factors. These findings add to our understanding of genetic and environmental mechanisms underlying the biological clock.

The Genesis 12–19 (G1219) Study: A Twin and Sibling Study of Gene–Environment Interplay and Adolescent Development in the UK

The Genesis 12–19 (G1219) Study is an ongoing longitudinal study of a sample of UK twin pairs, non-twin sibling pairs, and their parents. G1219 was initially designed to examine the role of gene–environment interplay in adolescent depression. However, since then data have continued to be collected from both parents and their offspring into young adulthood. This has allowed for longitudinal analyses of depression and has enabled researchers to investigate multiple phenotypes and to ask questions about intermediate mechanisms. The study has primarily focused on emotional development, particularly depression and anxiety, which have been assessed at multiple levels of analysis (symptoms, cognitions, and relevant environmental experiences). G1219 has also included assessment of a broader range of psychological phenotypes ranging from antisocial behaviors and substance use to sleep difficulties, in addition to multiple aspects of the environment. DNA has also been collected. The first wave of data collection began in the year 1999 and the fifth wave of data collection will be complete before the end of 2012. In this article, we describe the sample, data collection, and measures used. We also summarize some of the key findings to date.