Heritability of insomnia symptoms in youth and their relationship to depression and anxiety

Examining the connection between weekend catch-up sleep and depression: Insights from 2017 to 2020 NHANES information

BACKGROUND

Depression, a prevalent mental disorder, has shown an increasing trend in recent years, imposing a significant burden on health and society. Adequate sleep has been proven to reduce the incidence of depression. This study seeks to explore how Weekend Catch-up Sleep (WCS) is connected with the prevalence of depression in the American population.

METHODS

The National Health and Nutrition Examination Survey (NHANES) provides representative data for the U.S.

POPULATION

We utilized data from the 2017-2018 and 2019-2020 cycles. Depression was operationally defined as a PHQ-9 score exceeding 10. WCS duration was categorized into five groups: no change in sleep duration (=0 h), decreased sleep duration (<0), short catch-up sleep duration (>0 h, ≤1 h), moderate catch-up sleep duration (>1 h, <2 h), and long catch-up sleep duration (≥2 h).

RESULTS

Among the 8039 individuals, the distribution of WCS duration was as follows: no change (WCS = 0 h) in 2999 individuals (37.3 %), decreased sleep (WCS < 0 h) in 1199 individuals (14.9 %), short catch-up sleep (0 h < WCS ≤ 1 h) in 1602 individuals (19.9 %), moderate catch-up sleep (1 h < WCS < 2 h) in 479 individuals (6.0 %), and long catch-up sleep (WCS ≥ 2 h) in 1760 individuals (21.9 %). Acting by adjustment for all covariates in a multiple regression analysis, we discovered that persons with 1 to 2 h of weekend catch-up sleep had a substantially low prevalence of depression concerning those with WCS = 0 (OR 0.22, 95 % CI 0.08-0.59, P = 0.007).

CONCLUSION

The prevalence of depression in individuals engaging in weekend catch-up sleep for 1 to 2 h is lower than those who do not catch up on weekends. This discovery on the treatment and prevention of depression provides a new perspective. However, further prospective research and clinical trials are needed for a comprehensive investigation.

Depression, anxiety, and insomnia symptoms among Chinese college students: A network analysis across pandemic stages

BACKGROUND

As the stages of the COVID-19 pandemic evolved, the symptoms of depression, anxiety, and insomnia have increasingly manifested among Chinese college students. The aim of this study is to investigate the relationships between these symptoms through network analysis among Chinese college students during COVID-19.

METHOD

A three-wave cross-sectional survey was conducted at 22 colleges in Guangdong Province, involving 381,152 students during three specific time intervals: T1 (baseline, February 3 to 10, 2020), T2 (19 months after baseline, June 10 to 18, 2021), and T3 (37 months after baseline, March 15 to April 22, 2023). Depression (PHQ-9), anxiety (GAD-7), and insomnia (YSIS) were used separately. We analyzed two key network indices: "Expected influence" and "Bridge expected influence". Network stability was assessed through a case-dropping bootstrap program.

RESULT

The effective sample sizes for the three periods were as follows: T1 - 164,101 (103,645 females, 63.2 %), T2 - 86,767 (52,146 females, 60.1 %), and T3 - 130,284 (76,720 females, 58.9 %). Across these three periods, the key central symptoms were "Fatigue" (PHQ4), "Restlessness" (GAD5), "Uncontrollable worrying" (GAD2), "Worry too much" (GAD3) and "Sleep insufficiency" (YSIS6). Notably, "Fatigue" (PHQ4), "Restlessness" (GAD5) and "Irritability" (GAD6) consistently served as bridge symptoms. In the T1 and T2 period, "Motor" (PHQ8) acted as a bridge symptom but weakened in T3.

CONCLUSION

Throughout the three periods, the mental health issues among Chinese college students displayed characteristics of somatization within the depression-anxiety-insomnia comorbidity network. Over time, anxiety symptoms appeared to become more prominent. Consequently, this study highlights the importance of accurately identifying and promptly intervening in these core symptoms of mental health among college students, as these symptoms may evolve across different stages of a pandemic.

Subtyping at-risk adolescents for predicting response toward insomnia prevention program

BACKGROUND

Previous study has shown that a brief cognitive-behavioral prevention insomnia program could reduce 71% risk of developing insomnia among at-risk adolescents. This study aimed to evaluate the differential response to insomnia prevention in subgroups of at-risk adolescents.

METHODS

Adolescents with a family history of insomnia and subthreshold insomnia symptoms were randomly assigned to a 4-week insomnia prevention program or nonactive control group. Assessments were conducted at baseline, 1 week, and 6- and 12-month after the intervention. Baseline sleep, daytime, and mood profiles were used to determine different subgroups by using latent class analysis (LCA). Analyses were conducted based on the intention-to-treat approach.

RESULTS

LCA identified three subgroups: (a) insomnia symptoms only, (b) insomnia symptoms with daytime sleepiness and mild anxiety, and (c) insomnia symptoms with daytime sleepiness, mild anxiety, and depression. The incidence rate of insomnia disorder over the 12-month follow-up was significantly reduced for adolescents receiving intervention in subgroup 3 compared with the controls (hazard ratio [HR] = 0.37; 95% confidence interval [CI]: 0.13-0.99; p = .049) and marginally for subgroup 2 (HR = 0.14; 95% CI: 0.02-1.08; p = .059). In addition, adolescents who received intervention in subgroups 2 and 3 had a reduced risk of excessive daytime sleepiness (subgroup 2: adjusted OR [AdjOR] = 0.45, 95% CI: 0.23-0.87; subgroup 3: AdjOR = 0.32, 95% CI: 0.13-0.76) and possible anxiety (subgroup 2: AdjOR = 0.47, 95% CI: 0.27-0.82; subgroup 3: AdjOR = 0.33, 95% CI: 0.14-0.78) compared with the controls over the 12-month follow-up.

CONCLUSIONS

Adolescents at risk for insomnia can be classified into different subgroups according to their psychological profiles, which were associated with differential responses to the insomnia prevention program. These findings indicate the need for further phenotyping and subgrouping at-risk adolescents to develop personalized insomnia prevention.

Network analysis of sleep bruxism in the EPISONO adult general population

Sleep bruxism (SB) has been associated with biological and psychosocial factors. The assessment of SB includes self-report, clinical evaluation, and polysomnography. This study aimed to investigate the associations of self-reported SB with other sleep disorders and demographic, psychological, and lifestyle factors in the adult general population, and to investigate whether self-reported SB and polysomnographically (PSG) confirmed SB provide similar outcomes in terms of their associated factors. We recruited 915 adults from the general population in Sao Paulo, Brazil. All participants underwent a one-night PSG recording and answered questions about sex, age, BMI, insomnia, OSA risk, anxiety, depression, average caffeine consumption, smoking frequency, and alcohol consumption frequency. We investigated the link between SB and the other variables in univariate, multivariate, and network models, and we repeated each model once with self-reported SB and once with PSG-confirmed SB. Self-reported SB was only significantly associated with sex (p = 0.042), anxiety (p = 0.002), and depression (p = 0.03) in the univariate analysis, and was associated with insomnia in the univariate (p < 0.001) and multivariate (β = 1.054, 95%CI 1.018-1.092, p = 0.003) analyses. Network analysis showed that self-reported SB had a direct positive edge to insomnia, while PSG-confirmed SB was not significantly associated with any of the other variables. Thus, sleep bruxism was positively associated with insomnia only when self-reported, while PSG-confirmed SB was not associated with any of the included factors.

Sleep Disorders and Fatigue among Patients with MS: The Role of Depression, Stress, and Anxiety

Sleep disorders and fatigue represent prominent symptoms frequently experienced by individuals with multiple sclerosis (MS). Some psychological factors such as depression, stress, and anxiety seem to have a relationship with such problems. This study aimed to examine the role of depression, stress, and anxiety in predicting sleep disorders and fatigue among patients with MS. Employing a cross-sectional descriptive-correlational design, the study involved a sample size of 252 participants selected through purposive sampling based on inclusion and exclusion criteria. We utilized a demographic information questionnaire along with the Mini-Sleep Questionnaire (MSQ), Fatigue Severity Scale (FSS), and Depression, Anxiety, and Stress Scale (DASS-21) to collect data and analyzed them applying SPSS22, incorporating statistical measures including Pearson correlation and regression. The results of the Pearson correlation coefficient showed that sleep disorders had a positive and significant relationship with depression (r = 0.56; P < 0.001), stress (r = 0.40; P < 0.001), and anxiety (r = 0.52; P < 0.001). There was no significant relationship between age and the development of sleep disorders in total score (r = -0.001; P < 0.985), but age had a relationship with insomnia (r = -0.146; P < 0.021) and oversleeping (r = 0.153; P < 0.015). Age and fatigue did not have a significant relationship as well (r = -0.044; P < 0.941). In addition, fatigue had a positive and significant relationship with depression (r = 0.52; P < 0.001), stress (r = 0.48; P < 0.001), and anxiety (r = 0.54; P < 0.001). The results of the regression analysis also showed that depression, stress, and anxiety predict 0.37% of the total variance of sleep disorders (F = 48.34; P < 0.001) and 0.35% of the total variance of fatigue (F = 44.64; P < 0.001). Our findings suggest that depression, stress, and anxiety play a significant role in predicting sleep disorders and fatigue among patients with MS. This study has been reported in accordance with the TREND checklist for nonrandomized trials.

Potential genetic and epigenetic mechanisms in insomnia: A systematic review

Insomnia is a stress-related sleep disorder conceptualised within a diathesis-stress framework, which it is thought to result from predisposing factors interacting with precipitating stressful events that trigger the development of insomnia. Among predisposing factors genetics and epigenetics may play a role. A systematic review of the current evidence for the genetic and epigenetic basis of insomnia was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) system. A total of 24 studies were collected for twins and family heritability, 55 for genome-wide association studies, 26 about candidate genes for insomnia, and eight for epigenetics. Data showed that insomnia is a complex polygenic stress-related disorder, and it is likely to be caused by a synergy of genetic and environmental factors, with stress-related sleep reactivity being the important trait. Even if few studies have been conducted to date on insomnia, epigenetics may be the framework to understand long-lasting consequences of the interaction between genetic and environmental factors and effects of stress on the brain in insomnia. Interestingly, polygenic risk for insomnia has been causally linked to different mental and medical disorders. Probably, by treating insomnia it would be possible to intervene on the effect of stress on the brain and prevent some medical and mental conditions.

Sleep disturbances and depression are bidirectionally associated among college student athletes across COVID-19 pandemic exposure classes

College athletes may be vulnerable to sleep disturbances and depression during the COVID-19 pandemic as a result of large shifts in social and athletic obligations. In a national sample of college athletes, we examined the associations between sleep disturbances and depression across two timepoints, using COVID-19 exposure as a moderator. Data were collected from 2098 NCAA Division I, II, and III college athletes during two timepoints, from April 10 to May 23, and from August 4 to September 15, 2020. First, a latent class analysis was conducted with five indicators of levels of COVID-19 exposure to determine different exposure profiles. Second, to examine the directionality of associations between sleep disturbance and depression, a cross-lagged panel model was added to the latent class membership structural equation model; this allowed for testing of moderation by COVID exposure class membership. Four highly homogeneous, well-separated classes of COVID-19 exposure were enumerated: Low Exposure (57%); Quarantine Only (21%); High Other, Low Self Exposure (14%); and High Exposure (8%). COVID-19 exposure class membership did not significantly moderate associations between sleep disturbances and depression. However, student athletes significantly differed in T2 depression by their COVID-19 exposure class membership. Depression and sleep disturbances were positively correlated at both timepoints (r _T1 = 0.39; r _T2 = 0.30). Additionally, cross-lagged associations were found such that T2 depression was associated with T1 sleep disturbances (β = 0.14) and vice versa (β = 0.11). These cross-lagged associations were not significantly affected by athletes' level of COVID-19 exposure during the beginning of the pandemic.

Association of changes in sleep duration and quality with incidence of depression: A cohort study

BACKGROUND

The longitudinal relationship between sleep duration, sleep quality, and their changes with the risk of depressive symptoms is unclear. We examined the association between sleep duration, sleep quality, and their changes with incident depressive symptoms.

METHODS

A total of 225,915 Korean adults without depression at baseline with a mean age of 38.5 years were followed for an average of 4.0 years. Sleep duration and quality were assessed using the Pittsburgh Sleep Quality Index. The presence of depressive symptoms was assessed using the Center for Epidemiologic Studies Depression scale. Flexible parametric proportional hazard models were used to determine hazard ratios (HRs) and 95 % confidence intervals (CIs).

RESULTS

In total, 30,104 participants with incident depressive symptoms were identified. Multivariable-adjusted HRs (95 % CIs) for incident depression comparing sleep durations of ≤5, 6, 8, and ≥9 h with 7 h were 1.15 (1.11-1.20), 1.06 (1.03-1.09), 0.99 (0.95-1.03), and 1.06 (0.98-1.14), respectively. A similar trend was observed in patients with poor sleep quality. Compared with participants with persistently good sleep quality, participants with persistently poor sleep quality or who developed poor sleep quality were associated with the risk of incident depressive symptoms [HRs (95 % CIs) of 2.13 (2.01-2.25) and 1.67 (1.58-1.77), respectively].

LIMITATIONS

Sleep duration was assessed using self-reported questionnaire and the study population may not reflect general population.

CONCLUSIONS

Sleep duration, sleep quality and their changes were independently associated with incident depressive symptoms in young adults, suggesting that inadequate sleep quantity and quality play a role in depression risk.

Sex differences in sleep quality and psychological distress: Insights from a middle-aged twin sample from Spain

There is a moderate association between poor sleep and psychological distress. There are marked sex differences in the prevalence of both variables, with females outnumbering males. However, the origin of these sex differences remains unclear. The objectives of this study were to: (1) study genetic and environmental influences on the relationship between poor sleep quality and psychological distress; and (2) test possible sex differences in this relationship. The sample comprised 3544 participants from the Murcia Twin Registry. Univariate and multivariate twin models were fitted to estimate the magnitude of genetic and environmental influences on both individual variance and covariance between poor sleep quality and psychological distress. Sleep quality and psychological distress were measured using the Pittsburgh Sleep Quality Index and the EuroQol five-dimensions questionnaire, respectively. The results reveal a strong genetic association between poor sleep quality and psychological distress, which accounts for 44% (95%CI: 27%-61%) of the association between these two variables. Substantial genetic (rA = 0.50; 95%CI: 0.32, 0.67) and non-shared environmental (rE = 0.41; 95%CI: 0.30, 0.52) correlations were also found, indicating a moderate overlap between genetic (and non-shared environmental) factors influencing both phenotypes. Equating sexes in sex-limitation models did not result in significant decreases in model fit. Despite the remarkable sex differences in the prevalence of both poor sleep quality and psychological distress, there were no sex differences in the genetic and environmental influences on these variables. This suggests that genetic factors play a similar role for men and women in explaining individual differences in both phenotypes and their relationship.

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.

Longitudinal associations between parent, child, family factors and dyssomnias in children from birth to 8 years: The CIKEO study

BACKGROUND

Dyssomnias, are the most common parent-reported sleep complaints in young children. The present study investigated the prevalence, one-year development (incidence and persistence) of dyssomnia in early childhood, and the parent, child, and family factors associated with dyssomnia.

METHODS

Longitudinal data of 700 children aged 0-8, gathered in the CIKEO cohort study in the Netherlands were analyzed. Dyssomnias were defined as the presence of night awakenings ≥3 times per night or sleep-onset latency of >30 min. Least absolute shrinkage and selection operator (LASSO) was used to identify the parental, child, and family factors associated with the incidence and persistence of dyssomnias in children.

RESULTS

The mean age of the children (47 % girls) was 3.2 ± 1.9 years at baseline and 4.4 ± 1.8 years at follow-up. The prevalence of dyssomnias was 13.3 % and 15.4 % at baseline and follow-up, respectively. The incidence and persistence rates of dyssomnias at follow-up were 12.0 % and 37.6 %, respectively. New incidence of insomnia was associated with being a girl, having medical conditions, experiencing stressful life events, and lower parenting self-efficacy at baseline (P < 0.05). Higher levels of parental psychological distress were associated with the persistence of dyssomnias in children (P < 0.05).

CONCLUSIONS

Dyssomnias are common with a moderate persistent rate in young children. Several parental, child, and family factors in relation to the incidence and persistence of dyssomnias were identified. Preventive programs and interventions targeting modifiable factors, particularly parental psychological distress, parenting self-efficacy, and resilience to stressful life events, might benefit child sleep.

Sleep Duration and Internalizing Symptoms in Children

OBJECTIVE

Emotional problems such as anxiety and low mood have been associated with sleep problems in children. The study's objectives were to 1) assess the association between sleep duration and internalizing symptoms (anxiety and low mood) in children aged 5-12 years (y), and 2) evaluate whether insufficient sleep according to the National Sleep Foundation (NSF) guidelines is associated with internalizing symptoms.

METHODS

A cross-sectional study of N =796 children aged 5-12y, recruited from primary care physicians' offices in Toronto, Canada was conducted through the TARGet Kids! research network. Using linear regression, we investigated 1) the cross-sectional association between parent reported 24-hour sleep duration (hours) and parent reported symptoms using the Strengths and Difficulties Questionnaire (SDQ), controlling for child age, sex, family income, maternal education, family composition, and standardized body-mass index (zBMI). The analysis was repeated using insufficient sleep per NSF guideline as the independent variable.

RESULTS

Sleep duration was inversely associated with internalizing symptoms, B estimate = -0.33 (95%CI -0.57, -0.07), p=0.012. Twenty-eight (14%) children aged 5 y, and 36 (6%) of those aged 6-12y, experienced insufficient sleep. There was a trend toward association between insufficient sleep and internalizing symptoms, B estimate = 0.64 (-0.09, 1.38), p=0.086.

CONCLUSION

The relationship between insufficient sleep and internalizing symptoms among children requires further elucidation. Children who show internalizing symptoms may benefit from interventions supporting sleep.

Comparison of the Differences in State-Trait Anxiety Inventory Scores and Insomnia Histories between Monozygotic and Dizygotic Twins: A Cross-Sectional Study Using KoGES HTS Data

The heritability of anxiety and its association with insomnia have been suggested. This study investigated the coincidence of anxiety and insomnia in monozygotic twins compared to dizygotic twins. The Korean Genome and Epidemiology Study 2005–2014 was used. The ≥20-year-old cohort population was composed of 1300 twin participants. A total of 980 monozygotic twins and 232 dizygotic twins were compared for the concordance for the history of insomnia in both twin pairs (coincidence of insomnia) and the difference in state of anxiety and trait of anxiety scores. The odds ratios (ORs) for the coincidence of insomnia in monozygotic twins compared to dizygotic twins were analyzed using multiple logistic regression analysis. The estimated values (EV) of the difference of state and trait of anxiety scores were analyzed using a linear regression model. The coincidence of insomnia was not high in monozygotic twins compared to dizygotic twins. The difference in the state of anxiety score was comparable between monozygotic twins and dizygotic twins. However, the difference in anxiety scores was higher in dizygotic twins than in monozygotic twins. The monozygotic twin group did not demonstrate higher coincidence of insomnia or the state of anxiety than the dizygotic twin group. However, the monozygotic twin group indicated higher coincidence of the trait of anxiety than the dizygotic twins. The current results implied the potential contribution of heritable factors for the trait of anxiety.

The brain structure and genetic mechanisms underlying the nonlinear association between sleep duration, cognition and mental health

Sleep duration, psychiatric disorders and dementias are closely interconnected in older adults. However, the underlying genetic mechanisms and brain structural changes are unknown. Using data from the UK Biobank for participants primarily of European ancestry aged 38-73 years, including 94% white people, we identified a nonlinear association between sleep, with approximately 7 h as the optimal sleep duration, and genetic and cognitive factors, brain structure, and mental health as key measures. The brain regions most significantly underlying this interconnection included the precentral cortex, the lateral orbitofrontal cortex and the hippocampus. Longitudinal analysis revealed that both insufficient and excessive sleep duration were significantly associated with a decline in cognition on follow up. Furthermore, mediation analysis and structural equation modeling identified a unified model incorporating polygenic risk score (PRS), sleep, brain structure, cognition and mental health. This indicates that possible genetic mechanisms and brain structural changes may underlie the nonlinear relationship between sleep duration and cognition and mental health.

Trajectories of Insomnia Symptoms From Childhood Through Young Adulthood

OBJECTIVES

Insomnia symptoms are transdiagnostic to physical and mental health disorders. Given the lack of population-based cohorts with objective sleep measures and long-term follow-ups, little is known about the chronicity of childhood insomnia symptoms. We determined the developmental trajectories of insomnia symptoms, their evolution into adult insomnia, and the role of objective sleep duration in the transition to adulthood.

METHODS

A total of 502 children (median 9 years old, 71.7% response rate) were studied 7.4 years later as adolescents (median 16 years old) and 15 years later as adults (median 24 years old). Insomnia symptoms were ascertained as moderate-to-severe difficulties initiating and/or maintaining sleep via parent- or self reports at all 3 time points, adult insomnia via self-report in young adulthood, and objective short-sleep duration via polysomnography in childhood and adolescence.

RESULTS

Among children with insomnia symptoms, the most frequent trajectory was persistence (43.3%), followed by remission (26.9% since childhood, 11.2% since adolescence) and a waxing-and-waning pattern (18.6%). Among children with normal sleep, the most frequent trajectory was persistence (48.1%), followed by developing insomnia symptoms (15.2% since adolescence, 20.7% in adulthood) and a waxing-and-waning pattern (16.0%). The odds of insomnia symptoms worsening into adult insomnia (22.0% of children, 20.8% of adolescents) were 2.6-fold and 5.5-fold among short-sleeping children and adolescents, respectively.

CONCLUSIONS

Early sleep interventions are a health priority because pediatricians should not expect insomnia symptoms to developmentally remit in a high proportion of children. Objective sleep measures may be clinically useful in adolescence, a critical period for the adverse prognosis of the insomnia with short-sleep duration phenotype.

Pre-pregnancy sleep duration and postpartum depression: a multicenter study in Japan

Postpartum depression (PPD) is as a major public health issue and clinical priority worldwide. This study aimed to investigate the association between pre-pregnancy sleep duration and PPD. A multicenter retrospective study was conducted using clinical data of women who delivered at term between 2014 and 2018 at 12 maternity care hospitals in Japan. A total of 15,314 women were stratified into five groups according to their pre-pregnancy sleep duration: < 6, 6-7, 7-8, 8-9, and ≥ 9 h. Univariate and multivariate regression analyses were conducted to determine whether pre-pregnancy sleep duration affects the Edinburgh Postnatal Depression Scale (EPDS) scores at 1 month postpartum. We also evaluated whether the risk for PPD differs between primipara and multipara women classified according to pre-pregnancy sleep duration. The adjusted odds ratio for high EPDS scores (≥ 9) among women who slept for < 6 h and 6-7 h was 2.08 (95% confidence interval [CI]: 1.60-2.70) and 1.41 (95% CI: 1.18-1.68), respectively, relative to that in women with 7-8 h of sleep as the reference group. A 1-h increase in sleep duration was associated with an approximately 14% reduction in the risk for high EPDS scores. The association between short sleep duration and high EPDS scores was more remarkable in multipara women than in primipara women. Short pre-pregnancy sleep duration is associated with high EPDS scores, and this association is more significant in multipara women than in primipara women. Our findings emphasize the importance of collecting information on pre-pregnancy sleep duration to identify women at a high risk for PPD.

Childhood Maltreatment, Sleep Disturbances, and Anxiety and Depression: A Prospective Longitudinal Investigation

This research sought to determine whether inadequate sleep conditions in childhood and sleep problems in young adulthood in part explain the relationship between childhood abuse and neglect and anxiety and depression later in life. Children with documented histories of abuse and neglect and matched controls were followed up and assessed in young and middle adulthood. Abused and neglected children were more likely to report experiencing inadequate sleep conditions in childhood, sleep problems in young adulthood, and higher levels of depression and anxiety later in middle adulthood. Results revealed significant indirect paths from childhood maltreatment to anxiety and depression in middle adulthood through inadequate sleep conditions in childhood and sleep problems in young adulthood. This longitudinal follow-up of children with documented cases of maltreatment reveals the important role of sleep disturbances in the lives of maltreated children and adults and sleep disturbances in the development of subsequent anxiety and depression.

Predictors of diagnostically defined insomnia in child and adolescent community samples: a literature review

Diagnostically defined insomnia is prevalent, persistent, and associated with a range of negative outcomes in childhood and adolescence. To inform prevention and treatment, we need to identify relevant predictors that can be addressed in such intervention efforts. Therefore, a systematic search for longitudinal studies involving child and adolescent samples (ages 4 to 19) examining predictors of diagnostically defined insomnia adjusted for previous insomnia was conducted. The search identified 6419 studies, resulting in six included papers involving five samples (n = 9949) conducted in five different countries (the US, New Zealand, Norway, China, and Japan). Few longitudinal studies investigated the predictors of diagnostically defined insomnia in children and adolescents, and insomnia is rarely defined according to diagnostic manuals. The results suggested that poor mental health (most notably depression) and female sex may be involved in the etiology of diagnostically defined insomnia. Stress might be the most modifiable factor identified. However, the diversity of the predictors studied in previous reports combined with the lack of replication prevent any firm conclusions from being drawn. This review serves as a summary of the best available evidence.

Assessing the causal associations of insomnia with depressive symptoms and subjective well-being: a bidirectional Mendelian randomization study

BACKGROUND

The interactions and associations between insomnia, depressive symptoms, and subjective well-being are complex, thus it is hard to explore the effect and direction of causalities. This bidirectional Mendelian randomization (MR) study was to assess the causal associations of insomnia with depressive symptoms and subjective well-being.

METHODS

Summary statistics for insomnia, depressive symptoms, and subjective well-being were obtained from three large-scale genome-wide association studies (GWAS) of European ancestry. MR analyses were mainly conducted with the inverse-variance-weighted (IVW) method. The weighted-median method, MR-Egger method, and MR-Pleiotropy RESidual Sum and Outlier (PRESSO) test were adopted to test whether the estimates were robust. The adjusted MR analysis was performed to avoid the effect of potential pleiotropy.

RESULTS

There was evidence to support a causal association between genetically predicted insomnia and depressive symptoms (beta (β) = 0.086, 95% confidence interval (CI) = 0.068 to 0.104, P = 8.6E-21). Meanwhile, genetically predicted depressive symptoms was associated with a higher risk of insomnia (β = 0.543, 95% CI = 0.331 to 0.754, P = 4.8E-07). Genetically predicted insomnia was negatively associated with subjective well-being (β = -0.043, 95% CI = -0.063 to -0.024, P = 1.2E-05). There was evidence of reverse causality between insomnia and subjective well-being (β = -0.821, 95% CI = -1.012 to -0.630, P = 4.0E-17).

CONCLUSIONS

MR analysis indicates bidirectional causal associations of insomnia with depressive symptoms and subjective well-being. People should give serious attention to and attempt to resolve the problems of insomnia, depressive symptoms, and subjective well-being, whichever comes first.

Polygenic Risk for Insomnia in Adolescents of Diverse Ancestry

Background: Insomnia is a common mental disorder, affecting nearly one fifth of the pre-adult population in the United States. The recent, largest genome-wide association study (GWAS) conducted on the United Kingdom Biobank cohort identified hundreds of significant single-nucleotide polymorphism (SNP), allowing the epidemiologists to quantify individual genetic predisposition in the subsequent studies via the polygenic risk scoring technique. The nucleotide polymorphisms and risk scoring, while being able to generalize to other adult populations of European origin, are not yet tested on pediatric and adolescent populations of diverse racial-ethnic backgrounds, and our study intends to fill these gaps.

Materials and Methods: We took the summary of the same United Kingdom Biobank study and conducted a polygenic risk score (PRS) analysis on a multi-ethnicity, pre-adult population provided by the Adolescent Brain Cognitive Development (ABCD) Study.

Results: The PRSs according to the significant nucleotide polymorphisms found in white British adults is a strong predictor of insomnia in children of similar European background but lacks power in non-European groups.

Conclusions: Through polygenic risk scoring, the knowledge of insomnia genetics summarized from a white adult study population is transferable to a younger age group, which aids the search of actionable targets of early insomnia prevention. Yet population stratification may prevent the easy generalization across ethnic lines; therefore, it is necessary to conduct group specific studies to aid people of non-European genetic background.

Inference of causal relationships between sleep-related traits and 1,527 phenotypes using genetic data

STUDY OBJECTIVE

Sleep is essential for both physical and mental health, and there is a growing interest in understanding how different factors shape individual variation in sleep duration, quality and patterns, or confer risk for sleep disorders. The present study aimed to identify novel inferred causal relationships between sleep-related traits and other phenotypes, using a genetics-driven hypothesis-free approach not requiring longitudinal data.

METHODS

We used summary-level statistics from genome-wide association studies and the latent causal variable (LCV) method to screen the phenome and infer causal relationships between seven sleep-related traits (insomnia, daytime dozing, easiness of getting up in the morning, snoring, sleep duration, napping, and morningness) and 1,527 other phenotypes.

RESULTS

We identify 84 inferred causal relationships. Among other findings, connective tissue disorders increase insomnia risk and reduce sleep duration; depression-related traits increase insomnia and daytime dozing; insomnia, napping, and snoring are affected by obesity and cardiometabolic traits and diseases; and working with asbestos, thinner, or glues may increase insomnia risk, possibly through an increased risk of respiratory disease or socio-economic related factors.

CONCLUSION

Overall, our results indicate that changes in sleep variables are predominantly the consequence, rather than the cause, of other underlying phenotypes and diseases. These insights could inform the design of future epidemiological and interventional studies in sleep medicine and research.

The heritability of insomnia: Systematic review and meta-analysis of twin studies

Twin studies have consistently found that genetic factors explain a substantial proportion of the variance for insomnia. However, studies vary widely in their heritability estimates. Therefore, this meta-analysis aimed to: 1) Estimate the mean heritability of insomnia; 2) Assess heterogeneity among twin studies of insomnia; and 3) Search and analyse characteristics of the studies (moderator variables) that may explain heterogeneity among estimates. For this purpose, separate meta-analyses were carried out for MZ and DZ correlations and for heritability estimates by assuming random-effects models. Thirteen independent samples were included in this meta-analysis. The heterogeneity index for heritability estimates was significant in both best fitting models (I² = 98.77, P < .0001) and full models (I² = 97.80, P < .0001). MZ correlations were higher (0.37; 95%CI: 0.31,.43) than DZ correlations (0.15; 95%CI: 0.12,.18). A mean heritability of 0.39 (95%CI: 0.32,.44) was found for insomnia. These results highlight the role of genetic factors in explaining differences among the population on insomnia and Emphasize heterogeneity among studies. Further research is needed to identify variables that could explain this heterogeneity.

Differential Co-Occurring Patterns Between Depressive Symptomatology and Sleep-Wake-Related Disturbances in Mood Disorders

PURPOSE

This study aimed to elucidate the various co-occurring patterns of depressive symptomatology and sleep-wake-related disturbances (SWRDs) in patients with mood disorders.

PATIENTS AND METHODS

Individuals in non-acute states of major depressive disorder or bipolar disorder were recruited. The Beck Depression Inventory II (BDI-II) was utilized to evaluate depressive symptoms. BDI-II items were classified into three domains: cognitive, affective, and somatic. Between-domain differences with various SWRDs were examined. Latent class analysis was used to empirically classify participants using BDI-II items as indicator variables. Co-occurring patterns between domains of BDI-II items and SWRDs were re-examined in each subgroup to elucidate inter-individual differences.

RESULTS

In total, 657 participants were enrolled. Of participants, 66.8% were female, and 52.4% were diagnosed with major depressive disorder. Each BDI-II domain exhibited different co-occurring patterns. The somatic domain was most likely to co-occur with various SWRDs. Three subgroups were derived from latent class analysis and were designated as poor sleep quality and high insomnia (n=150), poor sleep quality and moderate insomnia (n=248), and poor sleep quality and low insomnia (n=159). The group with more severe insomnia presented with more severe depressive and anxiety symptoms. The three subgroups further differed in co-occurring patterns. From the low insomnia to high insomnia group, the associations with various SWRDs appeared in the sequence of somatic, affective, and cognitive domains.

CONCLUSION

Co-occurring patterns between domains of depressive symptomatology with various SWRDs differ and may vary among individuals.

Sex-Specific Moderation Effect of Age on the Associations Between Insomnia Symptoms and Various Psychological Distresses

BACKGROUND

Insomnia is closely related to psychological distress. This study aims to examine the role of age and sex in the association between various psychological distresses and insomnia symptoms.

PARTICIPANTS AND METHODS

This population-based study used data provided by cumulative respondents of the annual survey of the Taiwan Suicide Prevention Center between 2006 and 2019. Potential respondents were aged ≥15 years and were selected by a stratified proportional randomization method according to the distribution of population size, sex, and age in different geographic areas of Taiwan. The Five-Item Brief Symptom Rating Scale was used to measure insomnia symptoms and four psychological distresses: depression, anxiety, hostility, and inferiority. The independent relationship between insomnia symptoms with depression, anxiety, hostility, and inferiority was further examined according to age and sex.

RESULTS

A total of 28,649 participants were included (women, 50.2%). The four types of psychological distress correlated differentially with insomnia symptoms. Concerning interaction effects, sex moderated the interaction effects between age with depression, anxiety, and hostility. In men, and not in women, age moderated the relationship between insomnia symptoms and all four psychological distresses. Specifically, the effect sizes of the associations between insomnia symptoms and depression, anxiety, and hostility showed an age-dependent decreasing trend in men.

CONCLUSION

The associations between psychological distresses and insomnia symptoms varied in strength and according to age in a sex-specific manner.

Maternal insomnia during the COVID-19 pandemic: associations with depression and anxiety

BACKGROUND

The COVID-19 outbreak has made people more prone to depression, anxiety and insomnia, and females are at a high risk of developing these conditions. As a special group, pregnant and lying-in women must pay close attention to their physical and mental health, as both have consequences for the mother and the fetus. However, knowledge regarding the status of depression, anxiety and insomnia among these women is limited.

AIM

This study aimed to examine insomnia and psychological factors among pregnant and lying-in women during the COVID-19 pandemic and provide theoretical support for intervention research.

METHODS

In total, 2235 pregnant and lying-in women from 12 provinces in China were surveyed; their average age was 30.25 years (SD = 3.99, range = 19-47 years).

PARTICIPANTS AND SETTING

The participants completed electronic questionnaires designed to collect demographic information and assess levels of depression, anxiety and insomnia.

RESULTS

The prevalence of insomnia in the sample was 18.9%. Depression and anxiety were significant predictors of insomnia. Participants in high-risk areas, those with a disease history, those with economic losses due to the outbreak, and those in the postpartum period had significantly higher insomnia scores.

DISCUSSION

The incidence of insomnia among pregnant and lying-in women is not serious in the context of the epidemic, which may be related to the sociocultural background and current epidemic situation in China.

CONCLUSION

Depression and anxiety are more indicative of insomnia than demographic variables.

The heritability of insomnia: A meta-analysis of twin studies

Twin studies of insomnia exhibit heterogeneity in estimates of heritability. This heterogeneity is likely because of sex differences, age of the sample, the reporter and the definition of insomnia. The aim of the present study was to systematically search the literature for twin studies investigating insomnia disorder and insomnia symptoms and to meta-analyse the estimates of heritability derived from these studies to generate an overall estimate of heritability. We further examined whether heritability was moderated by sex, age, reporter and insomnia symptom. A systematic literature search of five online databases was completed on 24 January 2020. Two authors independently screened 5644 abstracts, and 160 complete papers for the inclusion criteria of twin studies from the general population reporting heritability statistics on insomnia or insomnia symptoms, written in English, reporting data from independent studies. We ultimately included 12 papers in the meta-analysis. The meta-analysis focussed on twin intra-class correlations for monozygotic and dizygotic twins. Based on these intra-class correlations, the meta-analytic estimate of heritability was estimated at 40%. Moderator analyses showed stronger heritability in females than males; and for parent-reported insomnia symptoms compared with self-reported insomnia symptoms. There were no other significant moderator effects, although this is likely because of the small number of studies that were comparable across levels of the moderators. Our meta-analysis provides a robust estimate of the heritability of insomnia, which can inform future research aiming to uncover molecular genetic factors involved in insomnia vulnerability.

Sleep disturbance and psychiatric disorders

Signs of mental ill health that cut across psychiatric diagnostic categories at high rates are typically viewed as non-specific occurrences, downgraded in importance and disregarded. However, problems not associated with particular diagnoses should be expected if there is shared causation across mental health conditions. If dynamic networks of interacting symptoms are the reality of mental health presentations, then particularly disruptive and highly connected problems should be especially common. The non-specific occurrence might be highly consequential. One non-specific occurrence that is often overlooked is patients' chronic difficulty in getting good sleep. In this Review, we consider whether disrupted sleep might be a contributory causal factor in the occurrence of major types of mental health disorders. It is argued that insomnia and other mental health conditions not only share common causes but also show a bidirectional relationship, with typically the strongest pathway being disrupted sleep as a causal factor in the occurrence of other psychiatric problems. Treating insomnia lessens other mental health problems. Intervening on sleep at an early stage might be a preventive strategy for the onset of clinical disorders. Our recommendations are that insomnia is assessed routinely in the occurrence of mental health disorders; that sleep disturbance is treated in services as a problem in its own right, yet also recognised as a pathway to reduce other mental health difficulties; and that access to evidence-based treatment for sleep difficulties is expanded in mental health services.

Insomnia in Chinese College Students With Internet Addiction: Prevalence and Associated Clinical Correlates

Background: Internet addiction (IA) has gained more and more attention for its negative impact on the subjects' study and daily life. However, in a large sample, there is little research on the association between IA and insomnia in Chinese college students. This study aimed to investigate the prevalence of insomnia and its related risk factors among Chinese college students with IA. Methods: A cross-sectional design was used to investigate 627 Chinese college students with IA. Each student completed a survey on demographic data, Internet addiction (Revised Chinese Internet Addiction Scale), depression (Self-Rating Depression Scale), insomnia (Athens Insomnia Scale), anxiety (Self-Rating Anxiety Scale), and suicidal behavior. Binary logistic regression analysis was employed to adjust for confounding factors. Results: The prevalence of insomnia among students with IA was 54.86%. Compared with IA students without insomnia, IA students with insomnia were more likely to be younger, smoking, drinking, have anxiety, depression, suicidal ideations, suicide plans, and suicide attempts (all p < 0.05). Moreover, drinking [OR, 1.664; 95% confidence interval (CI), 1.139-2.431; p = 0.008], anxiety (OR, 2.321; 95% CI, 1.116-4.826; p = 0.024), and suicidal ideation (OR, 1.942; 95% CI:1.295-2.911; p = 0.001) were independently associated with insomnia in IA students. Conclusions: Insomnia is very common in Chinese IA students. Drinking, anxiety, and suicidal ideation are independently correlated with insomnia. This study provides valuable evidence for school counselors and clinical professionals to assess Internet addiction, insomnia, and suicide risk.

Child sleep and mother labour market outcomes

We show that sleep deprivation exerts strong negative effects on mothers' labour market performance. To isolate variations in maternal sleep, we exploit unique variations in child sleep disruption using a UK panel dataset that follows mother-child pairs through time. We find that sleeping one hour less per night on average significantly decreases maternal labour force participation, the number of hours worked and household income. We identify one mechanism driving the effects, namely the influence of maternal sleep on selection into full-time versus part-time work. Increased schedule flexibility for mothers with sufficient tenure mitigates the negative effects of sleep deprivation.

Sex differences in insomnia and risk for psychopathology in adolescence

This review examines sex differences in sleep disturbance and risk for psychopathology, with a particular focus on the emergence of insomnia and risk for depression among adolescents. Possible explanations for the female preponderance of adolescent insomnia is discussed. The significance of the temporal relationship between adolescent insomnia and depression is discussed, as the extant literature suggests that insomnia tends to precede depression more than the inverse. Whether a causal relationship may exist between the two conditions and possible mechanisms underlying sex differences are highlighted along with important areas for future research.

Sleep quality, insomnia, and internalizing difficulties in adolescents: insights from a twin study

Study Objectives

There is a well-established association between poor sleep quality and internalizing traits. This relationship has previously been studied using a twin design. However, when it comes to adolescence, there is a paucity of twin studies that have investigated this relationship, despite the importance of this developmental stage for both the development of poor sleep quality and internalizing symptoms. Additionally, anxiety sensitivity, which is commonly associated with poor sleep quality, has not been studied in this context. Our objective was to estimate genetic and environmental influences on the relationships between insomnia, poor sleep quality, and internalizing symptoms in adolescence.

Methods

Insomnia, poor sleep quality, depression, anxiety, and anxiety sensitivity traits were measured in a sample of 5111 twin pairs from the Twins Early Development Study, born between 1994 and 1996 (mean age 16.32 years [SD = 0.68]).

Results

A moderate proportion of the variance for the different variables (.29–.42) was explained by genetic factors. Associations between sleep and internalizing variables were moderate (r = .34–.46) and there was a large genetic overlap between these variables (rA= .51–.73).

Conclusion

This study adds novel information by showing that there are large genetic correlations between sleep disturbances and internalizing symptoms in adolescence.

The Effect of Anxiety and Depression on Sleep Quality of Individuals With High Risk for Insomnia: A Population-Based Study

Introduction: One of the most common sleep disorders, insomnia is a significant public health concern. Several psychiatric disorders, such as anxiety disorders and depression, have shown strong relationships with insomnia. However, the clinical impact of the combination of these two conditions on insomnia severity and sleep quality remains unknown. We investigated the relationship between sleep disturbance and psychiatric comorbidities in subjects with high risk for insomnia.

Methods: We analyzed data from a nation-wide cross-sectional survey of Korean adults aged 19 ~ 69 years conducted from November 2011 to January 2012. The survey was performed via face-to-face interviews using a structured questionnaire. We used the insomnia severity index (ISI) to evaluate insomnia and defined respondents with ISI scores of ≥10 were considered to be at high risk for insomnia. To diagnose anxiety and depression, we used the Goldberg anxiety scale (GAS) and Patient Health Questionnaire-9 (PHQ-9), respectively.

Results: Of the 2,762 respondents, 290 (10.5%) were classified as subjects with high risk for insomnia; anxiety [odds ratio (OR), 9.8; 95% confidence interval (CI), 7.3–13.1] and depression (OR, 19.7; 95% CI, 13.1–29.6) were more common in this population than in participants without insomnia. Of the participants with insomnia, 152 (52.4%) had neither anxiety nor depression, 63 (21.7%) only had anxiety, 21 (7.2%) only had depression, and 54 (18.6%) had both anxiety and depression. The group with both anxiety and depression was associated with worse scores on sleep-related scales than the other groups [high ISI, Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale]. The relationship between outcome measures (ISI and PSQI) and psychiatric problems was significant only when anxiety and depression were present. The PSQI has a significant mediation effect on the relationship between psychiatric comorbidities and insomnia severity.

Conclusion: Among the respondents with insomnia, psychiatric comorbidities may have a negative impact on daytime alertness, general sleep quality, and insomnia severity, especially when the two conditions are present at the same time. Clinicians should, therefore, consider psychiatric comorbidities when treating insomnia.

Depression in sleep disturbance: A review on a bidirectional relationship, mechanisms and treatment

Sleep disturbance is the most prominent symptom in depressive patients and was formerly regarded as a main secondary manifestation of depression. However, many longitudinal studies have identified insomnia as an independent risk factor for the development of emerging or recurrent depression among young, middle‐aged and older adults. This bidirectional association between sleep disturbance and depression has created a new perspective that sleep problems are no longer an epiphenomenon of depression but a predictive prodromal symptom. In this review, we highlight the treatment of sleep disturbance before, during and after depression, which probably plays an important role in improving outcomes and preventing the recurrence of depression. In clinical practice, pharmacological therapies, including hypnotics and antidepressants, and non‐pharmacological therapies are typically applied. A better understanding of the pathophysiological mechanisms between sleep disturbance and depression can help psychiatrists better manage this comorbidity.

The impact of stress on sleep: Pathogenic sleep reactivity as a vulnerability to insomnia and circadian disorders

Sleep reactivity is the trait-like degree to which stress exposure disrupts sleep, resulting in difficulty falling and staying asleep. Individuals with highly reactive sleep systems experience drastic deterioration of sleep when stressed, whereas those with low sleep reactivity proceed largely unperturbed during stress. Research shows that genetics, familial history of insomnia, female gender and environmental stress influence how the sleep system responds to stress. Further work has identified neurobiological underpinnings for sleep reactivity involving disrupted cortical networks and dysregulation in the autonomic nervous system and hypothalamic-pituitary-adrenal axis. Sleep reactivity is most pathologically and clinically pertinent when in excess, such that high sleep reactivity predicts risk for future insomnia disorder, with early evidence suggesting high sleep reactivity corresponds to severe insomnia phenotypes (sleep onset insomnia and short sleep insomnia). High sleep reactivity is also linked to risk of shift-work disorder, depression and anxiety. Importantly, stress-related worry and rumination may exploit sensitive sleep systems, thereby augmenting the pathogenicity of sleep reactivity. With the development of cost-effective assessment of sleep reactivity, we can now identify individuals at risk of future insomnia, shift-work disorder and mental illness, thus identifying a target population for preventive intervention. Given that insomniacs with high sleep reactivity tend to present with severe insomnia phenotypes, patient sleep reactivity may inform triaging to different levels of treatment. Future research on sleep reactivity is needed to clarify its neurobiology, characterize its long-term prospective associations with insomnia and shift-work disorder phenotypes, and establish its prognostic value for mental illness and other non-sleep disorders.

Overcoming insomnia: protocol for a large-scale randomised controlled trial of online cognitive behaviour therapy for insomnia compared with online patient education about sleep

INTRODUCTION

Insomnia is a major public health concern. While cognitive behaviour therapy for insomnia (CBT-I) is acknowledged as the best available intervention, there are unanswered questions about its wider dissemination, socioeconomic benefits and its impact on health resource utilisation. The aim of this randomised controlled trial (RCT) is to investigate the effectiveness of a fully automated online version of CBT-I compared with online patient education about sleep (PE). Outcome measures comprise changes in symptoms of insomnia, time off work due to sick leave as well as medication and health resource utilisation. Also, we will examine (i) putative mediators of the effects of CBT-I on insomnia severity and (ii) selected potential psycho-bio-social moderators of the effects of the interventions.

METHODS AND ANALYSIS

A parallel-group RCT will be conducted in a target sample of about 1500 adults recruited across Norway. Participants will complete an online screening and consent process. Those who meet eligibility criteria will be randomised to receive direct access to fully automated online CBT-I or to an online PE programme. The primary outcome is change in insomnia severity immediately postintervention; secondary outcomes are change in daytime functioning and other sleep measures postintervention and at 6-month and 24-month follow-up. Objective data from national registries will be obtained at two time points (1 year and 2 years post-treatment), allowing a mirror image study of preintervention and postintervention rates of sick leave, and of medication and healthcare utilisation by condition.

ETHICS AND DISSEMINATION

The study protocol was approved by the Regional Committee for Medical and Health Research Ethics in South East Norway (2015/134). Findings from the RCT will be disseminated in peer-reviewed publications and conference presentations. Exploratory analyses of potential mediators and moderators will be reported separately. User-friendly outputs will be disseminated to patient advocacy and other relevant organisations.

TRIAL REGISTRATION NUMBER

NCT02558647; Pre-results.

Hyperarousal and sleep reactivity in insomnia: current insights

Hyperarousal is a key component in all modern etiological models of insomnia disorder. Overall patterns in the literature suggest that over-active neurobiological and psychological systems contribute to difficulty sleeping. Even so, mixed results regarding the specific mechanisms linking hyperarousal to sleep disturbance limit current etiological conceptualizations. Similar basal arousal profiles between individuals with high vs low risk for insomnia in the absence of stress exposure suggest that dysregulated stress "response" rather than general hyperarousal may be a more pertinent marker of risk. In this report, we discuss evidence for hyperarousal in insomnia and explore the role of sleep reactivity. A trait characteristic, sleep reactivity is the degree to which stress disrupts sleep, manifesting as difficulty falling and staying asleep. Premorbid sleep reactivity has been shown to identify individuals at risk for future insomnia disorder, such as highly reactive sleepers (whose sleep systems are sensitive to stress) who are at elevated disease risk. Research points to genetics, family history of insomnia, gender, and environmental stress as factors that influence sleep reactivity. Importantly, stress-related cognitive-emotional reactivity (e.g., rumination, worry) may exploit the vulnerability of a highly reactive sleep system. We propose that sleep reactivity and cognitive-emotional reactivity may share a bidirectional relationship, conferring an insalubrious environment for sleep in response to stress. Future research on sleep reactivity is needed to identify its neurobiology, characterize its relationship with cognitive-emotional reactivity, and explore the potential clinical utility of sleep reactivity in treatment planning.

Mechanisms underlying the association between insomnia, anxiety, and depression in adolescence: Implications for behavioral sleep interventions

There is robust evidence of an association between insomnia, anxiety, and depression in adolescence. The aim of this review is to describe and synthesize potential mechanisms underlying this association and explore implications for the design of adolescent behavioral sleep interventions. Specifically, we examine whether insomnia symptoms are a mechanism for the development of internalizing symptoms in adolescence and whether sleep interventions are an effective treatment for both insomnia and internalizing symptoms in adolescence because they target the shared mechanisms underlying these disorders. Research using different methodologies points to the role of sequential, parallel, and interacting mechanisms. In this paper, we review a wide range of relevant biological (i.e., polymorphisms and dysregulation in serotonin, dopamine, and circadian clock genes; alterations in corticolimbic and mesolimbic brain circuits; cortisol reactivity to stress; inflammatory cytokine dysregulation; biased memory consolidation; changes in sleep architecture), psychological (i.e., cognitive inflexibility, interpretational biases, judgment biases, negative attribution styles, worry, rumination, biased attention to threat, dysfunctional beliefs and attitudes about sleep, misperception of sleep deficit), and social mechanisms (i.e., reduced and impaired social interactions, unhelpful parenting behaviors, family stress) and propose an integrative multilevel model of how these phenomena may interact to increase vulnerability to both insomnia and internalizing disorders. Several 'biopsychosocial' mechanisms hold promise as viable treatment targets for adolescent behavioral sleep interventions, which may reduce both insomnia and internalizing symptoms.

Restless Sleep and Variable Sleep Timing During Late Childhood Accelerate the Onset of Alcohol and Other Drug Involvement

OBJECTIVE

Limited prospective data indicate that premorbid sleep disturbances elevate the risk for subsequent alcohol and other drug problems, yet the implications for subsequent substance involvement trajectories remain unclear. In the present analyses, we examined risk associations between sleep characteristics during late childhood and the onset of substance use and substance use disorders into adulthood.

METHOD

A sample of 707 children was recruited at ages 9-13 years and followed over seven additional visits through age 30 years. In 304 participants, fathers had a history of substance use disorder involving illicit drugs. Self-reported baseline sleep characteristics (restless sleep and variable sleep timing) were assessed at approximately ages 9-13 years. Assessment of alcohol, cannabis, and cocaine involvement occurred at follow-up visits. Cox proportional hazard models tested sleep characteristics as predictors of two substance-related outcomes (age at first use or diagnosis of disorder), as well as the onset of major depressive disorder.

RESULTS

Restless sleep at baseline significantly predicted an earlier onset age for trying alcohol and cannabis and showed a trend toward predicting early onset of cannabis use disorder. Restless sleep also predicted an earlier onset of depression. Irregular sleep timing at baseline significantly predicted an earlier onset age for alcohol use disorder and showed trends toward predicting early onsets of disorders of cannabis and cocaine use.

CONCLUSIONS

Disturbed sleep during late childhood appears to accelerate the onset of not only initial substance use but also the development of clinically defined substance use disorder. Sleep-focused preventative efforts during late childhood may reduce the incidence of mood and substance use disorders.

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.

Genetic Pathways to Insomnia

This review summarizes current research on the genetics of insomnia, as genetic contributions are thought to be important for insomnia etiology. We begin by providing an overview of genetic methods (both quantitative and measured gene), followed by a discussion of the insomnia genetics literature with regard to each of the following common methodologies: twin and family studies, candidate gene studies, and genome-wide association studies (GWAS). Next, we summarize the most recent gene identification efforts (primarily GWAS results) and propose several potential mechanisms through which identified genes may contribute to the disorder. Finally, we discuss new genetic approaches and how these may prove useful for insomnia, proposing an agenda for future insomnia genetics research.

A Longitudinal Twin and Sibling Study of Associations between Insomnia and Depression Symptoms in Young Adults

STUDY OBJECTIVES

To estimate genetic and environmental influences on the associations between insomnia and depression symptoms concurrently and longitudinally.

METHODS

Behavioral genetic analyses were conducted on data from the British longitudinal G1219 twin/sibling study. One thousand five hundred fiftysix twins and siblings participated at Time 1 (mean age = 20.3 years, SD = 1.76). Eight hundred sixty-two participated at Time 2 (mean age = 25.2 years, SD = 1.73 years). Participants completed the Insomnia Symptoms Questionnaire and the Short Mood and Feelings Questionnaire to assess symptoms of insomnia and depression respectively.

RESULTS

Genetic effects accounted for 33% to 41% of the variance of the phenotypes. The phenotypic correlations were moderate (r = 0.34 to r = 0.52). The genetic correlations between the variables were high (0.73-1.00). Genetic effects accounted for a substantial proportion of the associations between variables (50% to 90%). Non-shared environmental effects explained the rest of the variance and covariance of the traits.

CONCLUSIONS

While genetic effects play a modest role in insomnia and depression symptoms separately, they appear to play a more central role in concurrent and longitudinal associations between these phenotypes. This should be acknowledged in theories explaining these common associations.

Co-Morbidity, Mortality, Quality of Life and the Healthcare/Welfare/Social Costs of Disordered Sleep: A Rapid Review

Sleep disorders are frequent (18%-23%) and constitute a major risk factor for psychiatric, cardiovascular, metabolic or hormonal co-morbidity and mortality. Low social status or income, unemployment, life events such as divorce, negative lifestyle habits, and professional requirements (e.g., shift work) are often associated with sleep problems. Sleep disorders affect the quality of life and impair both professional and non-professional activities. Excessive daytime drowsiness resulting from sleep disorders impairs efficiency and safety at work or on the road, and increases the risk of accidents. Poor sleep (either professional or voluntary) has detrimental effects comparable to those of major sleep disorders, but is often neglected. The high incidence and direct/indirect healthcare and welfare costs of sleep disorders and poor sleep currently constitute a major medical problem. Investigation, monitoring and strategies are needed in order to prevent/reduce the effects of these disorders.

Day workers suffering from a wider range of sleep problems are more likely to experience suicidality

Both a higher suicide rate and widespread sleep problems are serious health concerns in Japan when compared with those of other countries. We investigated the relationship between suicidal ideation and sleep problems in Japanese day workers using the 3-dimensional sleep scale (3DSS), which measures three sleep elements (phase, quality, and quantity). Data from 635 Japanese day workers (461 mens and 174 womens) were included. The 3DSS was used to assess participants' sleep condition. Participants were classified into eight sleep types based on scores of phase, quality, and quantity: All Good Sleep, Owl (poor phase), Inefficient (poor quality), Short (poor quantity), Owl + Inefficient (poor phase and quality), Owl + Short (poor phase and quantity), Inefficient + Short (poor quality and quantity), and All Poor Sleep. We assessed participants' suicidal ideation using question 19 of the self-rating depression scale (SDS); 119 cases (18.7 %) had ratings of 2-4 for this question and were considered to have suicidal ideation. The higher the number of sleep problems, the higher the risk of suicidal ideation compared to sleep types not indicative of problems. All Poor Sleep had the highest risk of the eight sleep types. Individuals with Owl + Short, Inefficient + Short, or All Poor Sleep had a significant risk of suicidal ideation even after adjusting for hopelessness and nightmares. Our findings suggested that sleep problems assessed by the 3DSS were related to suicidal ideation. Analysis of various aspects of sleep could be helpful for suicide prevention.