Sleep reactivity and insomnia: genetic and environmental influences

Hyperarousal dynamics reveal an overnight increase boosted by insomnia

Hyperarousal is a key symptom of anxiety, stress-related disorders, and insomnia. However, it has been conceptualized in many different ways, ranging from various physiological markers (e.g. cortisol levels, high-frequency EEG activity) to personality traits, or state assessments of subjective anxiety and tension. This approach resulted in partly inconsistent evidence, complicating unified interpretations. Crucially, no previous studies addressed the likely variability of hyperarousal within and across days, nor the relationship of such variability in hyperarousal with the night-by-night variability in sleep quality characteristic of insomnia. Here, we present a novel data-driven approach to understanding dynamics of state hyperarousal in insomnia. Using ecological momentary assessment, we tracked fluctuations in a wide range of emotions across 9 days in 169 people with insomnia disorders and 38 controls without sleep problems. Exploratory factor analysis identified a hyperarousal factor, comprised of items describing tension and distress. People with insomnia scored significantly higher on this factor than controls at all timepoints. In both groups, the hyperarousal factor score peaked in the morning and waned throughout the day, pointing to a potential contributing role of sleep or other circadian processes. Importantly, the overnight increase in hyperarousal was stronger in people with in insomnia than in controls. Subsequent adaptive LASSO regression analysis revealed a stronger overnight increase in hyperarousal across nights of worse subjective sleep quality. These findings demonstrate the relationship between subjective sleep quality and overnight modulations of hyperarousal. Disorders in which hyperarousal is a predominant complaint might therefore benefit from interventions focused on improving sleep quality.

Individualized approaches to pediatric chronic insomnia: Advancing precision medicine in sleep disorders

The manifestations of chronic insomnia undergo age-related changes. In younger infants and children, behavioral insomnia emerges as the most prevalent form and typically responds to behavioral interventions. However, distinct clusters of clinical presentations suggest the presence of various phenotypes, potentially implicating the primary involvement of specific neurotransmitters. These conceptualizations, coupled with genetic studies on pleiotropy and polygenicity, may aid in identifying individuals at risk of persistent insomnia into adulthood and shed light on novel treatment options. In school-age children, the predominant presentation is sleep-onset insomnia, often linked with nighttime fears, anxiety symptoms, poor sleep hygiene, limit-setting issues, and inadequate sleep duration. The manifestations of insomnia in adolescence correlate with the profound changes occurring in sleep architecture, circadian rhythms, and homeostatic processes. The primary symptoms during adolescence include delayed sleep onset, sleep misperception, persistent negative thoughts about sleep, and physiological hyperarousal-paralleling features observed in adult insomnia. An approach centered on distinct presentations may provide a framework for precision-based treatment options. Enhanced comprehension of insomnia's manifestations across diverse developmental stages can facilitate accurate assessment. Efforts to subtype insomnia in childhood align with this objective, potentially guiding the selection of appropriate treatments tailored to individual neurobiological, clinical, and familial features.

The Effect of Shift Work on Sleep Patterns of Paramedics in Saudi Arabia

Purpose

Shift work poses significant sleep health challenges for paramedics, affecting their ability to respond effectively in emergencies. This study aimed to evaluate the impact of shift work on sleep parameters among paramedics in Saudi Arabia, identifying key factors influencing insomnia.

Patients and Methods

A cross-sectional, online survey was conducted, gathering data on sociodemographic characteristics, work-related factors, sleep duration, and insomnia among paramedics in Saudi Arabia. The Athens Insomnia Scale was used to define insomnia. The association between shift work and sleep parameters was examined. Predictors of insomnia were identified through logistic regression models by inspecting the adjusted odds ratio (aOR).

Results

1076 Saudi paramedics were included, most of whom were 26-35 years old, males, married, had a Bachelor's degree, worked in hospital-based settings for private agencies in rural areas, and had 6-10 years of experience. Occupational stress was reported by 52.96% of paramedics. All shift work characteristics (working hours, number of shifts, work schedule, and off-work days) were significantly associated with insomnia (p=0.0001). The multivariate regression revealed that work setting (aOR=18.71, p=0.02), coffee consumption (aOR=36.83, p=0.01), work schedule (aOR=21.93, p=0.01), and time to bed (aOR=0.01, p=0.01), sleep duration (aOR=0.03, p=0.03), and occupation stress (aOR=9.31, p=0.001) were predictors for insomnia.

Conclusion

Our findings underscores the need for targeted interventions to mitigate the adverse effects of shift work on sleep health among paramedics.

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.

The sleep response to stress: how sleep reactivity can help us prevent insomnia and promote resilience to trauma

Sleep reactivity is a predisposition to sleep disturbance during environmental perturbations, pharmacological challenges, or stressful life events. Consequently, individuals with highly reactive sleep systems are prone to insomnia disorder after a stressor, engendering risk of psychopathology and potentially impeding recovery from traumatic stress. Thus, there is tremendous value in ameliorating sleep reactivity to foster a sleep system that is robust to stress exposure, ultimately preventing insomnia and its downstream consequences. We reviewed prospective evidence for sleep reactivity as a predisposition to insomnia since our last review on the topic in 2017. We also reviewed studies investigating pre-trauma sleep reactivity as a predictor of adverse post-traumatic sequelae, and clinical trials that reported the effect of behavioural treatments for insomnia on mitigating sleep reactivity. Most studies measured sleep reactivity via self-report using the Ford Insomnia Response to Stress Test (FIRST), demonstrating high scores on this scale reliably indicate a sleep system with a lower capacity to tolerate stress. Nascent evidence suggests elevated sleep reactivity prior to trauma increases the risk of negative posttraumatic outcomes, namely acute stress disorder, depression, and post-traumatic stress disorder. Lastly, sleep reactivity appears most responsive to behavioural insomnia interventions when delivered early during the acute phase of insomnia. Overall, the literature strongly supports sleep reactivity as a premorbid vulnerability to incident acute insomnia disorder when faced with an array of biopsychosocial stressors. The FIRST identifies individuals at risk of insomnia a priori, thereby guiding early interventions toward this vulnerable population to prevent insomnia and promote resilience to adversity.

Sleep Reactivity and Sleep Efforts in Shift Workers

OBJECTIVE

The current study aimed to investigate the differences in sleep reactivity and sleep effort differs among late night shift workers (LSWs) and non-late night shift workers (non-LSWs), and non-shift workers (non-SWs).

METHODS

In total, 6,023 participants (1,613 non-SWs, 3,339 LSWs, and 1,071 non-LSWs) were recruited. Non-SWs was defined as those who works at fixed schedules during standard daylight. LSWs was defined as who work late night hours (10 PM-6 AM), while non-LSWs was SWs who did not work during late night. All completed the Ford Insomnia Response to Stress Test (FIRST), the Glasgow Sleep Effort Scale (GSES), the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS), the Insomnia Severity Index (ISI), and the short-term Center for Epidemiologic Studies-Depression scale (CES-D) through online survey.

RESULTS

LSWs and non-LSWs reported higher FIRST, GSES scores than non-SWs. In addition, LSWs reported higher FIRST, GSES scores than non-LSWs. FIRST scores were correlated with CES-D, PSQI, ISI, and ESS for LSWs, non-LSWs, and non-SWs alike. GSES scores were also correlated with CES-D, PSQI, ISI, and ESS for LSWs, non-LSWs, and non-SWs alike.

CONCLUSION

SWs showed higher sleep reactivity and sleep effort than non-SWs. LSWs had higher sleep reactivity and sleep effort than non-LSWs, and these variables are associated with insomnia, daytime sleepiness, and depressive symptoms. Our findings suggests that late night schedule, may increase sleep reactivity and sleep effort, which are associated with sleep and mood disturbances.

Improved resilience following digital cognitive behavioral therapy for insomnia protects against insomnia and depression one year later

BACKGROUND

While the negative consequences of insomnia are well-documented, a strengths-based understanding of how sleep can increase health promotion is still emerging and much-needed. Correlational evidence has connected sleep and insomnia to resilience; however, this relationship has not yet been experimentally tested. This study examined resilience as a mediator of treatment outcomes in a randomized clinical trial with insomnia patients.

METHODS

Participants were randomized to either digital cognitive behavioral therapy for insomnia (dCBT-I; n = 358) or sleep education control (n = 300), and assessed at pre-treatment, post-treatment, and 1-year follow-up. A structural equation modeling framework was utilized to test resilience as a mediator of insomnia and depression. Risk for insomnia and depression was also tested in the model, operationalized as a latent factor with sleep reactivity, stress, and rumination as indicators (aligned with the 3-P model). Sensitivity analyses tested the impact of change in resilience on the insomnia relapse and incident depression at 1-year follow-up.

RESULTS

dCBT-I resulted in greater improvements in resilience compared to the sleep education control. Furthermore, improved resilience following dCBT-I lowered latent risk, which was further associated with reduced insomnia and depression at 1-year follow-up. Sensitivity analyses indicated that each point improvement in resilience following treatment reduced the odds of insomnia relapse and incident depression 1 year later by 76% and 65%, respectively.

CONCLUSIONS

Improved resilience is likely a contributing mechanism to treatment gains following insomnia therapy, which may then reduce longer-term risk for insomnia relapse and depression.

Linking repetitive negative thinking and insomnia symptoms: A longitudinal trait-state model

Sleep disturbance is highly debilitating, and an abundance of research suggests that repetitive negative thinking (i.e., rumination, worry) may contribute to the development and maintenance of maladaptive sleep patterns, such as insomnia symptoms. Although repetitive negative thinking is often conceptualized as a 'trait' risk factor for anxiety-related disorders, it is unclear if it consists of time-varying (TV) or state-like features versus time-invariant (TI) or trait-like characteristics. Furthermore, it is unclear if it is the TV or TI components of repetitive negative thinking that contribute to insomnia symptoms that is commonly observed in anxiety-related disorders. In a 6-wave, 5-month longitudinal study, community participants (N = 1219) completed measures of rumination, worry, transdiagnostic repetitive negative thinking, and insomnia symptoms. A latent variable (trait-state-occasion) model was applied to the measures of repetitive negative thinking. The results showed that although estimates of TI factor variance and TV factor variance were both significant for latent repetitive negative thinking, worry, and rumination, the proportion of TI factor variance (0.82-0.89) was greater than the amount of TV factor variance (0.11-0.19). Although TV factor stability was statistically significant for latent repetitive negative thinking, rumination, and worry, the magnitude of the coefficients was small. Furthermore, regression weights for the latent repetitive negative thinking, rumination, and worry TI factor were significant and larger than those for the TV factor in predicting insomnia symptoms at each of the six time points. These findings suggest that repetitive negative thinking is largely TI, and it is this TI component that contributes to insomnia symptoms. Implications for conceptualizations of repetitive negative thinking as a predisposing and perpetuating factor in insomnia for anxiety and related disorders are discussed.

Associations between exposure to phthalates, phenols, and parabens with objective and subjective measures of sleep health among Mexican women in midlife: a cross-sectional and retrospective analysis

Endocrine-disrupting chemicals (EDCs) may impact sleep during the menopausal transition by altering sex hormones. However, these studies are scarce among Latin American women. This investigation utilized cross-sectional and retrospective data from midlife women enrolled in the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) study to examine associations between exposure to EDCs (phthalates, phenols, and parabens) and sleep health measures. For cross-sectional analyses, single spot urine samples were collected between 2017-2019 from a pilot sample of women (N = 91) of midlife age to estimate the urinary concentration of individual phthalates, phenols, and parabens and to calculate the summary concentration of phthalate mixtures. Seven-day nightly sleep duration, midpoint, and fragmentation were obtained from wrist-actigraphy devices and estimated from the actigraphy data using a pruned dynamic programming algorithm. Self-reported poor sleep quality was assessed by one item from the Pittsburgh Sleep Quality Index (PSQI). We examined associations between urinary summary phthalate mixtures, phthalate metabolites, phenol, and paraben analytes with each sleep measure using linear or logistic (to compute odds of poor sleep quality only) regression models adjusted for specific gravity, age, and socioeconomic status. We ran similar regression models for retrospective analyses (N = 74), except that urine exposure biomarker data were collected in 2008 when women were 24-50 years old. At the 2017-2019 midlife visit, 38% reported poor sleep quality. Cross-sectionally, EDCs were associated with longer sleep duration, earlier sleep timing, and more fragmented sleep. For example, every 1-unit IQR increase in the phenol triclosan was associated with a 26.3 min per night (95% CI: 10.5, 42.2; P < 0.05) longer sleep duration and marginally associated with 0.2 decimal hours (95% CI: -0.4, 0.0; P < 0.10) earlier sleep midpoint; while every 1-unit IQR increase in the phthalate metabolite MEHP was associated with 1.1% higher sleep fragmentation (95% CI: 0.1, 2.1; P < 0.05). Retrospective study results generally mirrored cross-sectional results such that EDCs were linked to longer sleep duration, earlier sleep timing, and more fragmented sleep. EDCs were not significantly associated with odds of self-reported poor sleep quality. Results from cross-sectional and retrospective analyses revealed that higher exposure to EDCs was predictive of longer sleep duration, earlier sleep timing, and more fragmented sleep among midlife women.

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.

Daily reactivity to stress and sleep disturbances: unique risk factors for insomnia

STUDY OBJECTIVES

To naturalistically measure sleep disturbances following stress exposure (i.e. sleep reactivity) and stress responses following sleep disturbances (i.e. stress reactivity) at the daily level and prospectively examine these reactivity measures as individual risk factors for insomnia.

METHODS

The study assessed 392 nurses' sleep and stress for 14 days using daily diaries and actigraphy. Self-reported insomnia symptoms were assessed at the end of the 14 days, as well as 6 and 11 months later.

RESULTS

In multilevel modeling, while negative fixed effects indicated that shorter total sleep time (TST) and lower sleep efficiency led to greater stress and vice versa, significant random effects indicated individual variability in sleep reactivity and stress reactivity. In latent score change modeling, greater sleep reactivity (lower diary-determined sleep efficiency following greater stress) and greater stress reactivity (greater stress following shorter diary-determined TST) at baseline were associated with greater insomnia symptoms at 11 months (b = 10.34, p = .026; b = 7.83, p = .03). Sleep reactivity and stress reactivity also interacted to predict insomnia symptoms, such that sleep reactivity was significantly associated with insomnia symptoms for those with high (+1 SD) stress reactivity (b = 17.23, p = .001), but not for those with low (-1 SD) stress reactivity (b = 5.16, p = .315).

CONCLUSIONS

Baseline stress reactivity and sleep reactivity independently as well as jointly predict greater insomnia symptoms 11 months later. The findings delineate processes underlying the stress-diathesis model of insomnia and highlight the utility of longitudinal and naturalistic measures of sleep and stress reactivity.

Insomnia is a key risk factor for persistent anxiety and depressive symptoms: A 12-month longitudinal cohort study during the COVID-19 pandemic

BACKGROUND

Insomnia is a risk factor for affective disorders. This study examined whether individuals with insomnia symptoms early in the pandemic, either pre-existing or new-onset, were more vulnerable to anxiety and depressive symptoms over time than those who maintained normal sleep. Additionally, sleep-related factors such as pre-sleep arousal were assessed for their influence on clinically significant anxiety and depression risk.

METHODS

Using a global online survey with 3-, 6-, and 12-month follow-ups between April 2020 and May 2021, data from 2069 participants (M = 46.16 ± 13.42 years; 75.3 % female) with pre-existing, new-onset, or no insomnia symptoms was examined using mixed-effects and logistic regression models.

RESULTS

New-onset and pre-existing insomnia predicted persistent anxiety and depressive symptoms longitudinally (p's < 0.001), over other known risk factors, including age, sex, and previous psychiatric diagnoses. Anxiety and depressive symptoms in both insomnia groups remained above clinically significant thresholds at most time points, whereas normal sleepers remained subclinical. Pre-sleep arousal was found to increase the risk of clinically significant anxiety (OR = 1.05) and depressive symptoms (OR = 1.09) at 12-months. Sleep effort contributed to anxiety (OR = 1.06), whereas dysfunctional sleep-related beliefs and attitudes predicted clinically significant depression (OR = 1.22).

LIMITATIONS

Insomnia group categorization was based on self-report at baseline supported by a validated measure. High participant attrition was observed at 3-months (53 %; n = 971), but retention remained steady till 12-months (63 %, n = 779).

CONCLUSIONS

Insomnia is a modifiable risk factor for persistent anxiety and depressive symptoms that needs to be addressed in mental healthcare. Additionally, pre-sleep arousal may be an important transdiagnostic process linking insomnia with affective disorders.

Adaptation and Validation of the Turkish Version of the Ford Insomnia Response to Stress Test in University Students

Objective

We adapted the Ford Insomnia Response to Stress Test to Turkish (FIRST-T) and validated it.

Methods

We randomly divided 774 Turkish university students into two equal groups for exploratory (EFA) and confirmatory factor analysis (CFA). McDonald's omega and Cronbach's alpha values were utilized for reliability analyses. Item response theory (IRT) approach also used for psychometric properties on the full sample. For discriminant validity, study sample were classified into high and low sleep reactivity groups, and their sociodemographic and sleep data were compared.

Results

EFA results suggested a one-factor structure of the FIRST-T, which was confirmed by CFA results. The FIRST-T had solid internal reliability. Item analysis results showed that all the items could distinguish between low and high scorers. This scale showed the same construct (clinical insomnia vs good sleepers) across the sexes in multi-group CFA and differential item functioning results. In the high FIRST-T score group, sleep quality, severity of insomnia, and anxiety scores were higher. In this group, more participants had clinical insomnia according to the Insomnia Severity Index (ISI) and were poor sleepers according to the Pittsburg Sleep Quality Index (PSQI) (p < 0.01).

Conclusion

The FIRST-T has robust psychometric properties that assesses sleep reactivity among university students.

The influence of sleep on fear extinction in trauma-related disorders

In Posttraumatic Stress Disorder (PTSD), fear and anxiety become dysregulated following psychologically traumatic events. Regulation of fear and anxiety involves both high-level cognitive processes such as cognitive reattribution and low-level, partially automatic memory processes such as fear extinction, safety learning and habituation. These latter processes are believed to be deficient in PTSD. While insomnia and nightmares are characteristic symptoms of existing PTSD, abundant recent evidence suggests that sleep disruption prior to and acute sleep disturbance following traumatic events both can predispose an individual to develop PTSD. Sleep promotes consolidation in multiple memory systems and is believed to also do so for low-level emotion-regulatory memory processes. Consequently sleep disruption may contribute to the etiology of PTSD by interfering with consolidation in low-level emotion-regulatory memory systems. During the first weeks following a traumatic event, when in the course of everyday life resilient individuals begin to acquire and consolidate these low-level emotion-regulatory memories, those who will develop PTSD symptoms may fail to do so. This deficit may, in part, result from alterations of sleep that interfere with their consolidation, such as REM fragmentation, that have also been found to presage later PTSD symptoms. Here, sleep disruption in PTSD as well as fear extinction, safety learning and habituation and their known alterations in PTSD are first briefly reviewed. Then neural processes that occur during the early post-trauma period that might impede low-level emotion regulatory processes through alterations of sleep quality and physiology will be considered. Lastly, recent neuroimaging evidence from a fear conditioning and extinction paradigm in patient groups and their controls will be considered along with one possible neural process that may contribute to a vulnerability to PTSD following trauma.

Sleep reactivity predicts insomnia in patients diagnosed with breast cancer

STUDY OBJECTIVES

To examine the role of sleep reactivity as a predictor of insomnia in patients diagnosed with breast cancer.

METHODS

A total of 173 women with breast cancer participated and were followed up over a period of 9 months. At baseline, participants were assigned to a high (n = 114) or low (n = 59) sleep reactivity group, based on their responses to the Ford Insomnia Response to Stress Test (FIRST). We assessed whether these FIRST groupings (high/low sleep reactivity) predicted changes in insomnia over time using the Insomnia Severity Index. We also tested if these FIRST groupings predicted insomnia disorder (using Insomnia Severity Index cutoffs) at 3 different time points (T3, T6, and T9).

RESULTS

Individuals with high sleep reactivity were more likely to experience a worsening of insomnia. Using logistic regression, we also found that FIRST grouping predicted insomnia disorder. Results remained significant after controlling for estimated premorbid sleep, age, and whether someone had chemotherapy.

CONCLUSIONS

Our study shows that sleep reactivity may be a robust predictor of insomnia within breast cancer populations. Sleep reactivity should be considered in routine clinical assessments as a reliable way to identify patients at risk of developing insomnia. This would facilitate early sleep intervention for those patients who are considered high risk.

CITATION

Rehman A, Drake CL, Shiramizu V, Fleming L. Sleep reactivity predicts insomnia in patients diagnosed with breast cancer. J Clin Sleep Med. 2022;18(11):2597-2604.

Insomnia – Is it a Symptom or a Disorder?

Insomnia disorder is a common public health problem with a prevalence of approximately 2-5% of the population. It is of major importance to differentiate the insomnia disorder from the isolated symptoms and normal variants, and to define the secondary or associated conditions. Insomnia was mainly classified as acute and chronic insomnia disorder based on the 3rd edition of the International Classification of Sleep Disorders. Many models have been developed to explain the underlying mechanisms of insomnia, such as the Drosophila model, the cognitive model, the psychobiological inhibition model, the neurocognitive model, stimulus control model, hyperarousal model and the “3P model” (Spielman model). Optimizing the environmental conditions, lifestyle changes and elaborating the triggering factors are the first step in the management of insomnia disorders.

Gene-environment interaction between circadian clock gene polymorphisms and job stress on the risk of sleep disturbances

RATIONALE

Sleep disturbances was associated with numerous adverse health outcomes. Many studies have reported that long-term exposure to job stress can lead to sleep disturbances, which may be influenced by genetic and environmental factors.

OBJECTIVES

This cross-sectional study investigated whether circadian clock gene polymorphisms modulated the influence of job stress on sleep disturbances in a Chinese Han population, which to our best knowledge has not been explored.

METHODS

The Effort-Reward Imbalance (ERI) scale and the Pittsburgh Sleep Quality Index (PSQI) were both used to access job stress and sleep disturbances. The SNaPshot SNP assay was carried out by screening for circadian clock gene polymorphisms in every participant. Interactions associated with sleep disturbances were assessed by linear hierarchical regression analysis and SPSS macros (PROCESS).

RESULTS

Linear hierarchical regression analysis showed that job stress was significantly related to sleep disturbances. Likewise, our study found a significant effect of PER2 rs2304672 polymorphisms on sleep disturbances (p < 0.01), after controlling for confounding factors. In addition, the PER2 rs2304672 genotype modulated the relationship between job stress and sleep disturbances (β = 0.414, p = 0.007). Interestingly, further analysis of the results of the PER2 gene rs2304672 × job stress interaction showed that rs2304672 G-allele carriers had a high-risk effect on sleep disturbances under high job stress.

CONCLUSIONS

Our results suggest that the PER2 rs2304672 polymorphism may modulate the influence of job stress on sleep disturbances. These findings contribute to the field of sleep disturbances prevention and treatment.

Is a blunted cortisol response to stress a premorbid risk for insomnia?

STUDY OBJECTIVES

Vulnerability to stress-related sleep disturbances (sleep reactivity) is an established heritable risk factor for insomnia disorder with unclear biological underpinnings. Preliminary research points to a blunted cortisol response to stress as a biological predisposition to familial risk for insomnia, but the role of cortisol response in sleep reactivity is unknown. Therefore, the current studies examined whether sleep reactivity is associated with a blunted cortisol response to two laboratory stressors among participants without insomnia.

METHODS

Two community samples of adults with no lifetime history of insomnia completed the Trier Social Stress Test (N = 35) or the Cold Pressor Task (N = 34). Participants were grouped by insomnia-risk using sleep reactivity scores from the Ford Insomnia Response to Stress Test (FIRST). Physiological responses were measured via markers of the hypothalamic-pituitary-adrenal (HPA) axis (salivary cortisol) and autonomic nervous system (ANS; heart rate, mean arterial pressure, and salivary alpha amylase).

RESULTS

Participants with high insomnia-risk (FIRST score > 18) exhibited blunted cortisol responses to both stressors. There were no group differences in ANS responses across stressors.

CONCLUSIONS

Insomnia-risk as indicated by sleep reactivity is associated with blunted cortisol responses to psychosocial and physical laboratory stressors among premorbid adults without insomnia disorder. This study replicates previous research and supports a blunted cortisol response to stress as a biomarker for insomnia vulnerability that may be detected using the FIRST. Prospective research is needed to elucidate whether a blunted cortisol response to stress is one mechanism by which sleep reactive individuals may be at risk of developing insomnia.

Sleep Disturbances During the Menopausal Transition: The Role of Sleep Reactivity and Arousal Predisposition

BACKGROUND

Sleep disturbances are common during the menopausal transition and several factors can contribute to this increased incidence. This study examined the association between sleep reactivity, arousal predisposition, sleep disturbances, and menopause.

METHODS

Data for this study were derived from a longitudinal, population-based study on the natural history of insomnia. A total of 873 women (40-60 years) were divided into two groups according to their menopausal status at baseline: reproductive (n = 408) and postmenopausal (n = 465). Participants were evaluated annually throughout the five-year follow-up period. Four questionnaires were used to examine sleep quality, insomnia severity, sleep reactivity, and arousal predisposition. The data were analyzed using two approaches: cross-sectional with a multivariate analysis and binary regression, and longitudinal with a linear mixed models using menopausal groups (3) x time (5) design.

RESULTS

Cross-sectional analyses showed that postmenopausal women reported significantly more severe insomnia and poorer sleep quality than reproductive women. Sleep reactivity and arousal predisposition were significant predictors of sleep disturbances. Longitudinal analyses revealed increased sleep disturbances in the two years before and after the menopausal transition. Sleep reactivity and arousal predisposition did not moderate the temporal relationship between menopausal transition and sleep disturbances.

CONCLUSION

More sleep disturbances were reported during the menopausal transition, but those difficulties were not explained by sleep reactivity and arousal predisposition. These results suggest the involvement of other psychophysiological factors in the development of sleep disturbances during the menopause.

Differences in Treatment Effects of Cognitive-behavioral Therapy for Insomnia Based on Sleep Reactivity: A Preliminary Study

INTRODUCTION

Sleep reactivity is the trait-like degree to which stress disrupts sleep, resulting in difficulty falling and staying asleep. Although previous studies have suggested that individuals who have high sleep reactivity may be resistant to cognitive-behavioral therapy for insomnia (CBT-I) effects, there have been no studies that have investigated this empirically. This study explored differential treatment responses in CBT-I based on sleep reactivity levels.

MATERIAL AND METHOD

Participants for this study were nineteen insomnia patients who met DSM-5 criteria for insomnia disorder. All participants received four weekly sessions of structured cognitive-behavioral therapy for insomnia (CBT-I). Individuals completed the Insomnia Severity Index (ISI), Korean version of Center for Epidemiologic Studies Depression Scale-Revised (K-CESD-R), Ford Insomnia Response to Stress Test (FIRST), Dysfunctional Beliefs and Attitudes about Sleep Scale-16 (DBAS-16), the Daily Inventory of Stressful Events (DISE) and a sleep diary. Participants were classified into two groups based on sleep reactivity level (high and low sleep reactivity).

RESULT

Following treatment, significant changes were found for ISI, K-CESD-R, DBAS-16 and FIRST scores, sleep onset latency, wake after sleep onset, sleep efficiency, number of awakenings, sleep quality and feeling refreshed upon awakening in both groups. Improvements in sleep efficiency was lower in the high sleep reactivity group compared to the low sleep reactivity group. No differences in ISI, K-CESD-R, DBAS-16 scores, and stress event frequency during the treatment duration were found between groups.

CONCLUSION

These findings suggest that sleep reactivity level may be an important factor that affects treatment outcome of CBT-I. Furthermore, the results may suggest that individual response to stress events are more important than the stressor itself.

Associations between burnout symptoms and sleep among workers during the COVID-19 pandemic

Background

Methods

Results

Conclusion

Emotion coping strategies and dysfunctional sleep-related beliefs are associated with objective sleep problems in young adults with insomnia

BACKGROUND

Though insomnia is associated with affected emotion regulation and dysfunctional ideas about sleep, little is known about the relation of these problems with objective sleep disruption. We aimed to explore this relationship in young adults with and without insomnia.

METHODS

Twenty young adults with diagnosed insomnia disorder (aged 27.7 ± 8.6 years) and twenty age-matched individuals without insomnia (26.7 ± 7.0 years) completed questionnaires, measuring sleep-related thoughts and emotions and emotion regulation. Objective sleep measurements were collected through 10-days actigraphy as a representative sample of nights, and analyzed for sleep onset latency, sleep efficiency total sleep time. T-tests and multivariate analyses of variance (MANOVA) were conducted for sample characterization and analysis of the association of sleep-related thoughts and emotions and emotion regulation with objective sleep data.

RESULTS

As expected, young people showed more dysfunctional sleep-related thoughts and emotions (all ps ≤ 0.025) and dysfunctional emotion regulation strategies (all ps ≤ 0.040). Surprisingly, MANOVA results showed that only emotion coping strategies after a stressful event (p = 0.017) and dysfunctional beliefs about sleep (p = 0.012), but not other factors of arousal or sleep reactivity, were associated with overall worse sleep, especially sleep onset latency (all ps ≤ 0.012) and sleep efficiency (all ps ≤ 0.010).

CONCLUSIONS

Maladaptive emotion coping strategies after a stressful event and dysfunctional sleep-related beliefs and attitudes affect objective sleep onset latency and sleep efficiency in young adults, highlighting the importance of targeting these features in the prevention and treatment of chronic insomnia and improving actual sleep quality.

Day-to-day associations between nightly sleep and next-day well-being amid the COVID-19 pandemic in North America

OBJECTIVE

Sleep may be especially important for maintaining health and well-being in daily life amid the stress of the coronavirus disease 2019 (COVID-19) pandemic. This preregistered study examined the associations of sleep quality, duration, and efficiency with next-day physical symptoms, affect, and stressors during the COVID-19 pandemic in North America, in addition to evaluating individual differences in COVID-19 threat as a moderator.

METHOD

From mid-March to early August 2020, 1025 adults from Canada and the United States aged 18-91 reported COVID-19 threat at baseline and subsequently completed twice-daily diaries for one week about their sleep, negative affect, stressors, and physical symptoms.

RESULTS

Within-persons, nights with better-than-usual sleep quality predicted lower next-day negative affect, physical symptoms, and stressor occurrence. Better-than-usual sleep efficiency and longer-than-usual sleep duration also predicted lower next-day physical symptoms. COVID-19 threat ratings moderated several of these associations, such that individuals with higher COVID-19 threat showed weaker within-person associations of sleep duration and efficiency with next-day well-being, compared to individuals with lower-to-moderate levels of COVID-19 threat. For the reversed direction of association, stressor occurrence predicted shorter-than-usual sleep that night, but no other links between daily well-being and subsequent sleep were observed.

DISCUSSION

Sleep quality, efficiency, and duration were important predictors of daily health and well-being during the COVID-19 pandemic, but the protective associations between sleep and next-day well-being were attenuated among people with higher COVID-19 threat. These findings highlight the role of heightened stress contexts when considering the benefits of sleep on daily health and well-being.

Heart Rate Variability, Sleep Quality, and Depression in the Context of Chronic Stress

BACKGROUND

Disrupted sleep quality is one of the proposed mechanisms through which chronic stress may lead to depression. However, there exist significant individual differences in sleep reactivity, which is the extent to which one experiences sleep disturbances in response to stress.

PURPOSE

The aim of the current study was to investigate whether low high-frequency heart rate variability (HRV), as a psychophysiological marker of poor emotional and physiological arousal regulation, predicts stress-related sleep disturbances associated with greater risk of depression symptoms.

METHODS

Using a chronic caregiving stress model, 125 mothers of adolescents with developmental disorders and 97 mothers of typically developing adolescents had their resting HRV and HRV reactivity recorded and completed a measure of depressive symptoms, as well as a 7 day sleep diary to assess their sleep quality. A moderated mediation model tested whether sleep quality mediated the association between chronic stress exposure and depressive symptoms and whether HRV moderated this mediation.

RESULTS

After controlling for participant age, body mass index, ethnicity, socioeconomic status, and employment status, poor sleep quality mediated the association between chronic stress and depressive symptoms. Resting HRV moderated this indirect effect such that individuals with lower HRV were more likely to report poorer sleep quality in the context of chronic stressor exposure, which, in turn, was related to greater depressive symptoms.

CONCLUSIONS

Lower HRV, a potential biomarker of increased sleep reactivity to stress, is associated with greater vulnerability to stress-related sleep disturbances, which, in turn, increases the risk for elevated depressive symptoms in response to chronic stress.

The relationship among sleep reactivity, job-related stress, and subjective cognitive dysfunction: a cross-sectional study using path analysis

Insomnia, job-related stress, and cognitive dysfunction affect the mental health of workers. However, the relationships among sleep reactivity, job-related stress, and subjective cognitive dysfunction in workers remains not fully understood. Therefore, this study seeks to investigate the relationships among these variables in Japanese adult workers. In total, 536 adult workers in Japan were evaluated using the Japanese version of Ford Insomnia Response to Stress Test, Brief Job Stress Questionnaire, and Cognitive Complaints in Bipolar Disorder Rating Assessment to assess sleep reactivity, job-related stress, and subjective cognitive function, respectively. Path analysis was also carried out. The results of the path analysis showed that sleep reactivity significantly influenced on subjective cognitive dysfunction directly and indirectly via job stressors and stress reaction. Our results may not be generalizable to underage workers because only adult workers were included, which is a limitation of this study. The results of the present study suggest that job-related stress mediates the effect of sleep reactivity on subjective cognitive dysfunction in Japanese adult workers. This underscores the need to evaluate the mediating effect of job-related stress in addressing the subjective cognitive dysfunction associated with insomnia in workers.

Sex- and age-specific genetic analysis of chronic back pain

ABSTRACT

Sex differences for chronic back pain (cBP) have been reported, with females usually exhibiting greater morbidity, severity, and poorer response to treatment. Genetic factors acting in an age-specific manner have been implicated but never comprehensively explored. We performed sex- and age-stratified genome-wide association study and single nucleotide polymorphism-by-sex interaction analysis for cBP defined as "Back pain for 3+ months" in 202,077 males and 237,754 females of European ancestry from UK Biobank. Two and 7 nonoverlapping genome-wide significant loci were identified for males and females, respectively. A male-specific locus on chromosome 10 near SPOCK2 gene was replicated in 4 independent cohorts. Four loci demonstrated single nucleotide polymorphism-by-sex interaction, although none of them were formally replicated. Single nucleotide polymorphism-explained heritability was higher in females (0.079 vs 0.067, P = 0.006). There was a high, although not complete, genetic correlation between the sexes (r = 0.838 ± 0.041, different from 1 with P = 7.8E-05). Genetic correlation between the sexes for cBP decreased with age (0.858 ± 0.049 in younger people vs 0.544 ± 0.157 in older people; P = 4.3E-05). There was a stronger genetic correlation of cBP with self-reported diagnosis of intervertebral disk degeneration in males than in females (0.889 vs 0.638; P = 3.7E-06). Thus, the genetic component of cBP in the UK Biobank exhibits a mild sex- and age-dependency. This provides an insight into the possible causes of sex- and age-specificity in epidemiology and pathophysiology of cBP and chronic pain at other anatomical sites.

Emotional Vulnerability to Short Sleep Predicts Increases in Chronic Health Conditions Across 8 Years

BACKGROUND

Sleep is a robust determinant of next-day emotions, but people vary in the extent that their emotions fluctuate on days following short sleep duration. These individual differences in day-to-day sleep and emotion dynamics may have long-term health implications.

PURPOSE

To evaluate emotional vulnerability to short sleep (within-person associations between sleep duration and next-day emotions) as a risk factor for future chronic conditions.

METHODS

Adults aged 33-84 (N = 1,426; 57% female) in the Midlife in the United States Study reported sleep duration and emotions by telephone for eight consecutive days. Chronic conditions were assessed via checklist at baseline and at a median follow-up of eight years (range: 5-10 years). Short sleep was examined in three ways: person-centered continuous variable, ≤6 hr, and <7 hr; long sleep was defined as ≥9 hr.

RESULTS

Multilevel structural equation models revealed that people with greater negative emotions following nights of sleep ≤6 hr (vs. their negative emotions after longer sleep) had increased chronic conditions at follow-up, compared to people who were less emotionally vulnerable to short sleep (Est. = 1.04, SE = .51, p < .028). Smaller declines in positive emotions following ≤6 hr of sleep were marginally predictive of lower risk for chronic conditions (Est. = -.77, SE = .44, p = .054). Emotional vulnerability to <7, ≥9, and continuous sleep hours were not associated with subsequent chronic conditions.

CONCLUSIONS

Emotional vulnerability to short sleep is a unique risk factor for the development of chronic conditions, independent of mean-level sleep duration and emotions.

What Do People Know About the Heritability of Sleep?

STUDY OBJECTIVES

Twin studies have provided data about the relative weight of genetic and environmental factors on sleep variables over the last few decades. However, heritability is a non-intuitive concept and it is often misunderstood even amongst the scientific community. This study aimed to analyze: (1) understanding of the meaning of heritability of insomnia; (2) the accuracy of estimations of heritability in the general population regarding three sleep traits (sleep duration, sleep quality and insomnia); (3) perceptions of the effectiveness of different treatments for insomnia depending on how the disorder is presented (i.e. having an environmental or genetic etiology) and whether the subject's estimate of genetic influence on sleep traits impacted beliefs about the effectiveness of different treatments.

METHODS

Participants (N = 3658) completed a survey which included: questions about general genetic knowledge; a specific question about the meaning of heritability; estimates of heritability of three different sleep traits; and the effectiveness of different treatments for insomnia depending on how the etiology of this condition was presented.

RESULTS

Fewer than 25% of the participants selected the correct description of the heritability of insomnia. Almost half of the sample incorrectly believed that heritability refers to the chance of passing a disorder onto their children. We also found that participants provided different estimates for the effectiveness of different treatments depending on the presumed etiology of the disorder.

CONCLUSION

Most people do not have accurate knowledge about the concept of heritability. People's assumptions about the etiology of a disorder may influence which treatments they consider most effective.

EEG spectral analysis in insomnia disorder: A systematic review and meta-analysis

Insomnia disorder (ID) has become the second-most common mental disorder. Despite burgeoning evidence for increased high-frequency electroencephalography (EEG) activity and cortical hyperarousal in ID, the detailed spectral features of this disorder during wakefulness and different sleep stages remain unclear. Therefore, we adopted a meta-analytic approach to systematically assess existing evidence on EEG spectral features in ID. Hedges's g was calculated by 148 effect sizes from 24 studies involving 977 participants. Our results demonstrate that, throughout wakefulness and sleep, patients with ID exhibited increased beta band power, although such increases sometimes extended into neighboring frequency bands. Patients with ID also exhibited increased theta and gamma power during wakefulness, as well as increased alpha and sigma power during rapid eye movement (REM) sleep. In addition, ID was associated with decreased delta power and increased theta, alpha, and sigma power during NREM sleep. The EEG measures of absolute and relative power have similar sensitivity in detecting spectral features of ID during wakefulness and REM sleep; however, relative power appeared to be a more sensitive biomarker during NREM sleep. Our study is the first statistics-based review to quantify EEG power spectra across stages of sleep and wakefulness in patients with ID.

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.

Advances in the Treatment of Chronic Insomnia: A Narrative Review of New Nonpharmacologic and Pharmacologic Therapies

Chronic insomnia disorder, which affects 6-10% of the population, is diagnostically characterized by ongoing difficulties with initiating or maintaining sleep occurring at least three times per week, persisting for at least 3 months, and associated with daytime impairment. While chronic insomnia is often considered a condition primarily related to impaired sleep, the disorder can also adversely affect domains of physical and mental health, quality of life, and daytime function, which highlights the importance of treating the multidimensional sleep disorder. Owing to misperceptions about the safety and effectiveness of treatment options, many individuals with insomnia may not seek professional treatment, and alternatively use ineffective home remedies or over-the-counter medications to improve sleep. Some physicians may even believe that insomnia is remediated by simply having the patient "get more sleep". Unfortunately, treatment of insomnia is not always that simple. The disorder's complex underlying pathophysiology warrants consideration of different nonpharmacologic and pharmacologic treatment options. Indeed, recent insights gained from research into the pathophysiology of insomnia have facilitated development of newer treatment approaches with more efficacious outcomes. This narrative review provides a summary of the diagnostic criteria and pathophysiology of insomnia and its subtypes. Further, this review emphasizes new and emerging nonpharmacologic and pharmacologic treatments for chronic insomnia, including recent enhancements in approaches to cognitive behavioral therapy for insomnia (CBT-I) and the new dual orexin receptor antagonist (DORA) pharmacologics. These advances in treatment have expanded the treatment options and are likely to result in improved outcomes in patients with chronic insomnia.

Insomnia May Mediate the Relationship Between Stress and Anxiety: A Cross-Sectional Study in University Students

BACKGROUND

High perceived stress and anxiety disorders are usually comorbid with each other, with stress often sequentially preceding the development of anxiety. While prior findings showed a causal role of sleep problems in anxiety, no study has assessed the role of insomnia as a mediator in the relationship between stress and anxiety.

METHODS

A cross-sectional study on university students (n = 475, age = 21.1+2.6 years) was conducted over 3 months. Participants completed self-report measures of Leeds Sleep Evaluation Questionnaire-Mizan (LSEQ-M), Perceived Stress Scale-10 (PSS-10), generalized anxiety disorder-7 scale (GAD-7), and a sociodemographic tool. The mediation effect model given by Baron and Kelly was used to determine the relationship.

RESULTS

The prevalence of insomnia and anxiety disorder was 43.6% and 21.9%, respectively. Stress was significantly associated with LSEQ-M (insomnia measure) (b = -.44, SE = 0.16, p<0.01), and high levels of anxiety (b = 0.25, SE = 0.03, p < 0.01). The indirect effect of stress on anxiety through LSEQ-M (insomnia measure) was significant (95% confidence interval [0.01, 0.04]). However, the indirect effect of anxiety on stress through LSEQ-M (insomnia measure) was non-significant (95% confidence interval [-.01, 0.04]).

CONCLUSIONS

Students having higher perceived stress levels and comorbid insomnia were also likely to have a higher anxiety level.

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.

Perfectionism and insomnia in adolescents: The role of vulnerability to stress and gender

INTRODUCTION

Perfectionism is an often overlooked yet consistent construct related to insomnia in the scientific literature. Perfectionism and insomnia are both highly prevalent in adolescence. However, there is a dearth of research examining mechanisms linking perfectionism with insomnia, particularly in young people. The current study aimed to investigate whether vulnerability to stress, a factor common to both constructs, accounts for the relationship between perfectionism and insomnia symptoms in a sample of adolescents.

METHODS

281 Australian participants (M_age = 16.53, SD = 1.91, range = 13-19 years, 78% female) completed questionnaires assessing perfectionism, vulnerability to stress and insomnia on one occasion.

RESULTS

Vulnerability to stress accounted for the relationship between self-oriented striving perfectionism, self-oriented critical perfectionism and insomnia symptom severity in females, but not males. Females reported higher self-oriented critical perfectionism, vulnerability to stress and insomnia severity, with a stronger relationship between vulnerability to stress and insomnia symptoms observed for females.

CONCLUSIONS

These results may partly explain the preponderance of insomnia in adolescent females. Possible implications for the prevention and treatment of insomnia in young people are discussed.

Brain mechanisms of insomnia: new perspectives on causes and consequences

While insomnia is the second most common mental disorder, progress in our understanding of underlying neurobiological mechanisms has been limited. The present review addresses the definition and prevalence of insomnia and explores its subjective and objective characteristics across the 24-hour day. Subsequently, the review extensively addresses how the vulnerability to develop insomnia is affected by genetic variants, early life stress, major life events, and brain structure and function. Further supported by the clear mental health risks conveyed by insomnia, the integrated findings suggest that the vulnerability to develop insomnia could rather be found in brain circuits regulating emotion and arousal than in circuits involved in circadian and homeostatic sleep regulation. Finally, a testable model is presented. The model proposes that in people with a vulnerability to develop insomnia, the locus coeruleus is more sensitive to-or receives more input from-the salience network and related circuits, even during rapid eye movement sleep, when it should normally be sound asleep. This vulnerability may ignite a downward spiral of insufficient overnight adaptation to distress, resulting in accumulating hyperarousal, which, in turn, impedes restful sleep and moreover increases the risk of other mental health adversity. Sensitized brain circuits are likely to be subjectively experienced as "sleeping with one eye open". The proposed model opens up the possibility for novel intervention studies and animal studies, thus accelerating the ignition of a neuroscience of insomnia, which is direly needed for better treatment.

Biofeedback Therapies for Chronic Insomnia: A Systematic Review

The treatment of insomnia is still a challenge in clinical practice. This systematic review of randomized and quasi-randomized clinical trials aims to summarize the evidence for the use of biofeedback techniques in the treatment of chronic insomnia. Studies that compared biofeedback with other techniques of cognitive behavioral therapy, placebo, or absence of treatment were selected. The outcomes evaluated included sleep onset latency, total sleep time, sleep fragmentation, sleep efficiency and subjective sleep quality. Comparing to placebo and absence of treatment, some studies suggest possible benefits from the use of biofeedback for chronic insomnia in decreasing sleep onset latency and number of awakenings; however, there was marked divergence among included studies. There was no evidence of improvement in total sleep time, sleep efficiency and subjective sleep quality. Moreover, the maintenance of long-term benefits lacks evidence for any outcome. In the majority of outcomes evaluated, no significant differences in the effectiveness of biofeedback compared with other cognitive behavioral therapy techniques were observed. This systematic review found conflicting evidence for the effectiveness of biofeedback techniques in the treatment of chronic insomnia. Inter- and intra-group clinical heterogeneity among studies could be a reasonable explanation for the divergent results. These findings emphasize the need of performing further randomized clinical trials of higher methodological quality in order to better delineate the effectiveness of biofeedback on chronic insomnia treatment.

Perceived Stress and Sleep Quality in Midlife and Later: Controlling for Genetic and Environmental Influences

OBJECTIVE/BACKGROUND

Stress is a strong predictor for poor sleep quality. However, little is known about the mechanism of this association or the respective contribution of genetic and environmental factors. This study aims to investigate general distress as a mediator and cognitive/emotional control as a moderator in the stress-sleep relationship and estimate the influence of gene and environment in this mechanism using a national representative sample.

PARTICIPANTS

1,255 middle-aged and elderly Americans and a subset of 296 twins.

METHODS

The Pittsburgh Sleep Quality Index, the Perceived Stress Scale, the Mood and Anxiety Symptom Questionnaire and the Self-Control Scale assessed sleep quality, perceived stress, general distress, and emotional/cognitive control. Structural equation modeling was used to test the mediating and moderating effect. ACE models on MZ and DZ twins were used to separate the contribution of genetic and environmental factors. Finally, a co-twin design was nested in the SEM to control for the genetic and familial confounds in the stress-sleep relationship.

RESULTS

General distress mediated the relationship between stress and sleep while emotional/cognitive control buffered the impact of stress on general distress. 7.69% of the variance in sleep quality was explained by genetic and familial factors and 8.26% was explained by individual-specific factors. Emotional/cognitive control only moderated the individual-specific association between stress and sleep.

CONCLUSIONS

Gene/family factors and individual factors explained an equivalent proportion of the stress-sleep relationship. The genetic and familial association between stress and sleep is more robust, whereas the individual-specific association can be buffered by regulation strategies.

Onset of regular cannabis use and young adult insomnia: an analysis of shared genetic liability

STUDY OBJECTIVES

Estimate the genetic and environmental influences on the relationship between onset of regular cannabis use and young adult insomnia.

METHODS

In a population-based twin cohort of 1882 twins (56% female, mean age = 22.99, SD = 2.97) we explored the genetic/environmental etiology of the relationship between onset of regular cannabis use and insomnia-related outcomes via multivariate twin models.

RESULTS

Controlling for sex, current depression symptoms, and prior diagnosis of an anxiety or depression disorder, adult twins who reported early onset for regular cannabis use (age 17 or younger) were more likely to have insomnia (β = 0.07, p = 0.024) and insomnia with short sleep on weekdays (β = 0.08, p = 0.003) as young adults. We found significant genetic contributions for the onset of regular cannabis use (a2 = 76%, p < 0.001), insomnia (a2 = 44%, p < 0.001), and insomnia with short sleep on weekdays (a2 = 37%, p < 0.001). We found significant genetic correlations between onset of regular use and both insomnia (rA = 0.20, p = 0.047) and insomnia with short sleep on weekdays (rA = 0.25, p = 0.008) but no significant environmental associations between these traits.

CONCLUSIONS

We found common genetic liabilities for early onset of regular cannabis use and insomnia, implying pleiotropic influences of genes on both traits.

Association between 5-hydroxytryptamine gene polymorphism rs140700 and primary insomnia in Chinese population

BACKGROUND

Primary insomnia is a worldwide problem and it has a considerable negative impact on one's physical and mental health. Studies have shown that non-synonymous Single-nucleotide polymorphisms in 5-hydroxytryptamine (serotonin or 5-HT) are related to primary insomnia. Previous studies have shown that 5-HT polymorphism (rs140700) is related to depression, and insomnia is often accompanied by depression and anxiety. The relationship between this site and primary insomnia is unknown. We speculated that this site may be related to primary insomnia, so we investigated the relationship between rs140700 and primary insomnia.

AIMS

To explore the relationship between the 5-HT gene polymorphism rs140700 and primary insomnia.

METHODS

In this study, we included 57 patients with primary insomnia and 54 age- and gender-matched normal controls. The subjects who belonged to the Chinese population were subjected to polysomnography for three consecutive nights. Their sleep quality was assessed, and the genotypes of the 5-hydroxytryptamine (5-HT) gene polymorphism rs140700 were determined by the flight mass spectrometry.

RESULTS

The genotype distributions of the 5-HT gene polymorphism rs140700 were in Hardy-Weinberg equilibrium in both patients and controls (P > 0.05). The allele and genotype distributions of this variant were comparable between the patients and controls in all subjects and between genders (all P > 0.05). The influence of rs140700 on percentage of stage 1 (P = 0.015) change and arousal index (P = 0.028) of primary insomnia was statistically significant. The logistic multi-factor regression analysis results revealed that 5-HT gene polymorphism rs140700 was not a risk factor for primary insomnia in the Chinese population (P = 0.589).

CONCLUSIONS

The 5-HT gene polymorphism rs140700 may not be a susceptibility locus for primary insomnia in the Chinese population.

Intraindividual variability in sleep and perceived stress in young adults

OBJECTIVES

Research suggests strong associations between habitual sleep parameters (eg, mean duration, timing, efficiency), perceived stress, and insomnia symptoms. The associations between intraindividual variability (IIV; night-to-night within-person variation) in sleep, perceived stress, and insomnia have not been explored. This study examined associations between IIV in subjectively and objectively determined sleep parameters and to perceived stress in young adults with and without insomnia.

DESIGN

Prospective longitudinal.

SETTING AND PARTICIPANTS

Participants were 149 college students (mean age = 20.2 [SD = 2.4], 59% female) either with insomnia (n = 81; 54%) or without insomnia (n = 68; 46%).

MEASUREMENTS

Participants completed 1 week of daily sleep diaries and actigraphy (to assess total sleep time [TST], sleep efficiency [SE], and circadian midpoint [CM]), the Perceived Stress Scale, and a diagnostic interview for determination of insomnia as part of a parent study.

RESULTS

Greater IIV in actigraphy-determined TST (but not SE or CM) was independently associated with greater perceived stress, regardless of insomnia status. Greater IIV in sleep diary-determined TST, SE, or CM was not associated with perceived stress. Insomnia status was the most robust predictor of elevated perceived stress. There was a significant interaction between IIV in sleep diary-determined TST and insomnia status on perceived stress: Only in those without insomnia was greater IIV in sleep diary-determined TST associated with higher perceived stress.

CONCLUSION

Maintaining a more consistent sleep duration may be associated with lower stress in college students. Future research is needed to clarify the directionality and implications of this association for treatment.

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.

Mindfulness and associations with symptoms of insomnia, anxiety and depression in early adulthood: A twin and sibling study

This study investigated associations between mindfulness and symptoms of insomnia, depression and anxiety. Mindfulness was disaggregated into five subscales: 'nonreactivity to inner experience', 'observing', 'acting with awareness', 'describing' and 'nonjudging of inner experience'. Twin models were used to examine genetic and environmental influences on mindfulness, symptoms of insomnia, depression and anxiety and on their associations. Data came from a longitudinal twin/sibling study (G1219) comprising 862 individuals (age range 22-32 years, 66% females). Less mindfulness was associated with greater symptoms of insomnia, depression and anxiety (r = .22-.48). Of the mindfulness subscales, 'nonjudging of inner experience' was most strongly associated with the other traits. Overall mindfulness was largely influenced by non-shared environmental factors (E = .72) although familial influences played a role for overall mindfulness, as well as for the 'acting with awareness' and 'describing' subscales. The genetic correlations between overall mindfulness and symptoms of insomnia, depression and anxiety ranged from .32 to .75 (but were non-significant), while the shared environmental correlations ranged from -.78 to .79 (also non-significant). The non-shared environmental influences between these three variables were moderately, significantly correlated (rE = .21-.55).

Obsessive-compulsive personality disorder features and response to behavioral therapy for insomnia among patients with hypnotic-dependent insomnia

Objective: To compare therapeutic response to behavioral therapy for insomnia (BT-I) among hypnotic-dependent insomnia (HDI) patients with and without Cluster C personality disorders. Participants: Twenty-three adults with HDI (17 females), aged between 33 and 68 (M = 53; SD = 9.9) were included in the study. Methods: Participants completed a personality disorder assessment (baseline), as well as sleep diaries, polysomnography (PSG), and an insomnia severity assessment (baseline, posttreatment, and one-year follow-up). Treatment consisted of eight weeks of individual BT-I and gradual hypnotic medication withdrawal. Multilevel mixed-effects linear regression models examined the interaction between study visit and Cluster C personality disorders status on treatment response to BT-I. Results: Obsessive-compulsive personality disorder (OCPD) was the most prevalent of the Cluster C personality disorders with 38% (n = 8) of participants meeting criteria. There were no significant treatment differences by OCPD status across time as measured by sleep diaries and insomnia severity status. However, there were significant treatment differences by OCPD status by one-year follow-up on PSG outcomes, indicating that patients with OCPD status had shorter and more disrupted sleep than patients without OCPD status. Conclusions: Based on self-reported sleep measures, patients with insomnia and features of OCPD responded equivalently to BT-I at one-year follow-up compared to patients without features of OCPD. However, polysomnography outcomes indicated objective sleep deteriorated in these patients, which may suggest greater vulnerability to relapse.

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.