Vulnerability to insomnia: the role of familial aggregation

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.

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.

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.

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.

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.

Mindfulness-Based Strategies for Improving Sleep in People with Psychiatric Disorders

PURPOSE OF THE REVIEW

To review the recent literature on mindfulness-based strategies for improving self-report and objective measures of sleep, in individuals with psychiatric disorders.

RECENT FINDINGS

Currently, research provides some support for the use of mindfulness-based interventions to improve sleep amongst individuals with psychiatric comorbidities. The strongest evidence was for the use of standardized programs, particularly for improving sleep in anxiety and depressive disorders. There is a paucity of well-controlled studies using validated subjective or objective measures of sleep. As these interventions were not specifically designed to target sleep, observed improvements may be an indirect consequence of reduced psychiatric symptoms. There is insufficient research into the application of mindfulness-based strategies to improve sleep or treat sleep disorders in people with psychiatric disorders. Well-controlled studies using standardized, mindfulness-based interventions developed to target sleep, such as mindfulness-based therapy for insomnia, may optimize the potential benefits of mindfulness for sleep in psychiatric populations.

Prior sleep problems and adverse post-traumatic neuropsychiatric sequelae of motor vehicle collision in the AURORA study

STUDY OBJECTIVES

Many patients in Emergency Departments (EDs) after motor vehicle collisions (MVCs) develop post-traumatic stress disorder (PTSD) or major depressive episode (MDE). This report from the AURORA study focuses on associations of pre-MVC sleep problems with these outcomes 8 weeks after MVC mediated through peritraumatic distress and dissociation and 2-week outcomes.

METHODS

A total of 666 AURORA patients completed self-report assessments in the ED and at 2 and 8 weeks after MVC. Peritraumatic distress, peritraumatic dissociation, and pre-MVC sleep characteristics (insomnia, nightmares, daytime sleepiness, and sleep duration in the 30 days before the MVC, trait sleep stress reactivity) were assessed retrospectively in the ED. The survey assessed acute stress disorder (ASD) and MDE at 2 weeks and at 8 weeks assessed PTSD and MDE (past 30 days). Control variables included demographics, MVC characteristics, and retrospective reports about PTSD and MDE in the 30 days before the MVC.

RESULTS

Prevalence estimates were 41.0% for 2-week ASD, 42.0% for 8-week PTSD, 30.5% for 2-week MDE, and 27.2% for 8-week MDE. Pre-MVC nightmares and sleep stress reactivity predicted 8-week PTSD (mediated through 2-week ASD) and MDE (mediated through the transition between 2-week and 8-week MDE). Pre-MVC insomnia predicted 8-week PTSD (mediated through 2-week ASD). Estimates of population attributable risk suggest that blocking effects of sleep disturbance might reduce prevalence of 8-week PTSD and MDE by as much as one-third.

CONCLUSIONS

Targeting disturbed sleep in the immediate aftermath of MVC might be one effective way of reducing MVC-related PTSD and MDE.

A negative cognitive style is associated with greater insomnia and depression symptoms: The mediating role of sleep reactivity

Insomnia and depression are distinct clinical phenomena, yet they are highly comorbid. One potential explanation for the high comorbidity rates is the overlap in risk factors. Atypical responses to stress, for example, place individuals at greater risk for both insomnia and depression. The goal of the present study was to simultaneously assess vulnerability to stress-related sleep disturbance (sleep reactivity) and the tendency to make negative attributions about stressful events (negative cognitive style), and how they relate to insomnia and depression. Study participants included 224 undergraduate students recruited from a large, public university in the United States. Sleep reactivity and negative cognitive style were assessed using the Ford Insomnia Response to Stress Test (FIRST) and the Cognitive Style Questionnaire (CSQ), respectively. Insomnia symptoms were assessed using the Insomnia Severity Index (ISI), and depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale (CES-D). Sleep reactivity was independently associated with greater insomnia and depression symptoms. Additionally, a negative cognitive style was related to greater depressive symptoms, and this effect was partially mediated by sleep reactivity. The current findings suggest that sleep reactivity may contribute to the development of disorders beyond insomnia. These findings further support the use of an interdisciplinary approach to investigating etiological models, and more specifically, the further exploration of how multiple stress responses (in terms of cognitions, sleep, etc.) place individuals at greater risk for developing psychopathology.

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.

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.

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.

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.

Assessing Stress-Induced Sleep Reactivity in College Students: The European Portuguese Version of the Ford Insomnia Response to Stress Test (FIRST)

OBJECTIVE AND BACKGROUND

Over the past few years, the comprehensive models of insomnia have exhibited impressive developments. However, there is scarce knowledge on predisposing or vulnerability factors for insomnia. One of the most promising constructs to aid in filling this gap is stress-induced sleep reactivity assessed through self-report. Our aim was to study the psychometric properties of the European Portuguese version of the Ford Insomnia Response to Stress Test (FIRST).

PARTICIPANTS

We recruited a large sample of students attending medical school (N = 699).

METHODS

Several analyses were carried out such as internal consistency, construct validity, and discriminant groups' analysis.

RESULTS

It was observed that FIRST-PT shows good internal consistency (Cronbach´s alpha = .81) and validity indicators. Interestingly, and contrary to what was observed in the previously published studies on psychometric properties of the FIRST, it was observed that a two-factor solution (Factor I = rumination, Factor II = worry) was the most adequate one to explain the correlation matrix, accounting for approximately 44% of the total variance.

CONCLUSIONS

The FIRST-PT proved to be a useful and reliable tool to measure stress-induced sleep reactivity. However, these results should be replicated in other groups, particularly clinical samples, in order to verify the stability of its factorial dimension.

Familial Risk for Insomnia Is Associated With Abnormal Cortisol Response to Stress

Objectives

Abnormalities in the stress system have been implicated in insomnia. However, studies examining physiological stress regulation in insomnia have not consistently detected differences in the hypothalamic-pituitary-adrenal (HPA)-axis response to stress. One explanation may be that deficits in the stress system are associated specifically with a biological vulnerability to insomnia rather than the phenotypic expression of insomnia. To examine stress response as a function of vulnerability to insomnia, this study tested response to the Trier Social Stress Test in a sample of healthy sleepers with varying familial risks for insomnia.

Methods

Thirty-five healthy individuals with and without familial risk for insomnia were recruited to complete a laboratory stressor. Participants with one or both biological parents with insomnia were categorized as positive for familial risk, whereas those without biological parents with insomnia were categorized as negative for familial risk. Participants completed the Trier Social Stress Test in the laboratory, and psychological and physiological (autonomic and HPA-axis) responses were compared.

Results

Despite self-reported increases in anxiety, those positive for familial risk exhibited a blunted cortisol response relative to those without familial risk for insomnia. Individuals with blunted cortisol also reported heightened reactivity to personal life stressors, including increased sleep disturbances, elevated cognitive intrusions, and more behavioral avoidance.

Conclusions

Findings from this study provide initial evidence that abnormal stress regulation may be a biological predisposing factor conferred via familial risk for insomnia. This deficit may also predict negative consequences over time, including insomnia and the associated psychiatric comorbidities.

Temporal Stability of the Ford Insomnia Response to Stress Test (FIRST)

STUDY OBJECTIVES

The Ford Insomnia Response to Stress Test (FIRST) is a self-report tool that measures sleep reactivity (i.e., vulnerability to experience situational insomnia under stressful conditions). Sleep reactivity has been termed a "trait-like" vulnerability; however, evidence of its long-term stability is lacking. The main objective of the current psychometric study was to investigate the temporal stability of the FIRST over two 6-mo intervals in a population-based sample of adults with and without insomnia. The temporal stability of the FIRST was also compared with the temporal stability of other scales associated with insomnia (trait-anxiety, arousability).

METHODS

Participants included 1,122 adults (mean age = 49.9 y, standard deviation = 14.8; 38.8% male) presenting with an insomnia syndrome (n = 159), insomnia symptoms (n = 152), or good sleep (n = 811). Participants completed the FIRST, the State-Trait Anxiety Inventory (trait-anxiety), and the Arousal Predisposition Scale (arousability) on three different occasions: baseline and at 6- and 12-mo follow-up. Intraclass correlation coefficients (ICCs) were computed for all scales (baseline to 6 mo and 6 to 12 mo).

RESULTS

The FIRST yielded strong temporal stability from baseline to 6 mo among those with insomnia syndrome (ICC = 0.81), symptoms (ICC = 0.78), and good sleep (ICC = 0.81). Similar results were observed for 6 to 12 mo among those with insomnia syndrome (ICC = 0.74), insomnia symptoms (ICC = 0.82), and good sleep (ICC = 0.84). The stability of the FIRST was not comparable with the stability of trait-anxiety, but was somewhat comparable with the stability of arousability.

CONCLUSIONS

Overall, the FIRST is a temporally reliable stable scale over 6-mo intervals. Future research is needed to corroborate the stability and trait-like measures of sleep reactivity with physiological, behavioural and personality measures.

Psychometric Evaluation of the Ford Insomnia Response to Stress Test (FIRST) in Early Pregnancy

STUDY OBJECTIVES

To evaluate the construct validity and factor structure of the Spanish-language version of the Ford Insomnia Response to Stress Test questionnaire (FIRST-S) when used in early pregnancy.

METHODS

A cohort of 647 women were interviewed at ≤ 16 weeks of gestation to collect information regarding lifestyle, demographic, and sleep characteristics. The factorial structure of the FIRST-S was tested through exploratory and confirmatory factor analyses (EFA and CFA). Internal consistency and construct validity were also assessed by evaluating the association between the FIRST-S with symptoms of depression, anxiety, and sleep quality. Item response theory (IRT) analyses were conducted to complement classical test theory (CTT) analytic approaches.

RESULTS

The mean score of the FIRST-S was 13.8 (range: 9-33). The results of the EFA showed that the FIRST-S contained a one-factor solution that accounted for 69.8% of the variance. The FIRST-S items showed good internal consistency (Cronbach α = 0.81). CFA results corroborated the one-factor structure finding from the EFA; and yielded measures indicating goodness of fit (comparative fit index of 0.902) and accuracy (root mean square error of approximation of 0.057). The FIRST-S had good construct validity as demonstrated by statistically significant associations of FIRST-S scores with sleep quality, antepartum depression and anxiety symptoms. Finally, results from IRT analyses suggested excellent item infit and outfit measures.

CONCLUSIONS

The FIRST-S was found to have good construct validity and internal consistency for assessing vulnerability to insomnia during early pregnancy.

Intimate Partner Violence Is Associated with Stress-Related Sleep Disturbance and Poor Sleep Quality during Early Pregnancy

Objectives

To examine the associations of Intimate partner violence (IPV) with stress-related sleep disturbance (measured using the Ford Insomnia Response to Stress Test [FIRST]) and poor sleep quality (measured using the Pittsburgh Sleep Quality Index [PSQI]) during early pregnancy.

Methods

This cross-sectional study included 634 pregnant Peruvian women. In-person interviews were conducted in early pregnancy to collect information regarding IPV history, and sleep traits. Adjusted odds ratios (aOR) and 95% confidence intervals (95%CIs) were calculated using logistic regression procedures.

Results

Lifetime IPV was associated with a 1.54-fold increased odds of stress-related sleep disturbance (95% CI: 1.08–2.17) and a 1.93-fold increased odds of poor sleep quality (95% CI: 1.33–2.81). Compared with women experiencing no IPV during lifetime, the aOR (95% CI) for stress-related sleep disturbance associated with each type of IPV were: physical abuse only 1.24 (95% CI: 0.84–1.83), sexual abuse only 3.44 (95%CI: 1.07–11.05), and physical and sexual abuse 2.51 (95% CI: 1.27–4.96). The corresponding aORs (95% CI) for poor sleep quality were: 1.72 (95% CI: 1.13–2.61), 2.82 (95% CI: 0.99–8.03), and 2.50 (95% CI: 1.30–4.81), respectively. Women reporting any IPV in the year prior to pregnancy had increased odds of stress-related sleep disturbance (aOR = 2.07; 95% CI: 1.17–3.67) and poor sleep quality (aOR = 2.27; 95% CI: 1.30–3.97) during pregnancy.

Conclusion

Lifetime and prevalent IPV exposures are associated with stress-related sleep disturbance and poor sleep quality during pregnancy. Our findings suggest that sleep disturbances may be important mechanisms that underlie the lasting adverse effects of IPV on maternal and perinatal health.

Immediate postarousal sleep dynamics: an important determinant of sleep stability in obstructive sleep apnea

Arousability from sleep is increasingly recognized as an important determinant of the clinical spectrum of sleep disordered breathing (SDB). Patients with SDB display a wide range of arousability. The reason for these differences is not known. We hypothesized that differences in the speed with which sleep deepens following arousals/awakenings (postarousal sleep dynamics) is a major determinant of these differences in arousability in patients with SDB. We analyzed 40 preexisting clinical polysomnography records from patients with a range of SDB severity (apnea-hypopnea index 5-135/h). Sleep depth was determined every 3 s using the odds ratio product (ORP) method, a continuous index of sleep depth (0 = deep sleep, 2.5 = full wakefulness) that correlates strongly (r = 0.98) with arousability (Younes M, Ostrowski M, Soiferman M, Younes H, Younes M, Raneri J, and Hanly P. Sleep 38: 641-654, 2015). Time course of ORP was determined from end of arousal until the next arousal. All arousals were analyzed (142 ± 65/polysomnogram). ORP increased from 0.58 ± 0.32 during sleep to 1.67 ± 0.35 during arousals. ORP immediately (first 9 s) following arousals/awakenings (ORP-9) ranged from 0.21(very deep sleep) to 1.71 (highly arousable state) in different patients. In patients with high ORP-9, sleep deepened slowly (over minutes) beyond 9 s but only if no arousals/awakenings recurred. ORP-9 correlated strongly with average non-rapid eye movement sleep depth (r = 0.87, P < 2E-13), the arousal/awakening index (r = 0.68, P < 5E-6), and with the apnea-hypopnea index (r = 0.60, P < 0.001). ORP-9 was consistent within each patient and did not change on continuous positive airway pressure despite marked improvement in sleep architecture. We conclude that postarousal sleep dynamics are highly variable among patients with sleep-disordered breathing and largely determine average sleep depth and continuity.

Childhood abuse is associated with stress-related sleep disturbance and poor sleep quality in pregnancy

OBJECTIVES

Childhood abuse is associated with increased risks of adult psychiatric disorders and physical health conditions. Mounting evidence documents associations of childhood abuse with sleep disturbances in adulthood. However, to date, no study has evaluated associations of childhood abuse and sleep disturbances among pregnant women.

METHODS

This cross-sectional study included 634 pregnant Peruvian women. To collect information regarding socio-demographic characteristics, history of childhood abuse, and complaints of sleep disturbances, face-to-face interviews were conducted with women in early pregnancy. Ford Insomnia Response to Stress Test (FIRST-S) and the Pittsburgh Sleep Quality Index (PSQI-S), translated from English to Spanish, were used to assess stress-related sleep disturbance and sleep quality, respectively. Logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (95% CIs).

RESULTS

Women who experienced any childhood abuse had a 1.65-fold increased odds of stress-related sleep disturbance (aOR = 1.65; 95% CI: 1.15-2.38) and 2.11-fold increased odds of poor sleep quality during early pregnancy (aOR = 2.11; 95% CI: 1.35-3.30) as compared with women who reported no abuse. Women who reported both physical and sexual abuse during childhood were more than twice as likely to suffer from stress-related sleep disturbance (aOR = 2.26; 95% CI: 1.44-3.53) and poor sleep quality (aOR = 2.43; 95% CI: 1.45-4.09) in comparison to women who reported no childhood abuse.

CONCLUSIONS

A history of childhood abuse is associated with increased odds of stress-related sleep disturbance and poor sleep quality during pregnancy. These findings, if replicated, should be used to inform the development of trauma-informed care for such sleep disturbances induced by childhood trauma.

Vulnerability to Stress-Related Sleep Disturbance and Insomnia: Investigating the Link with Comorbid Depressive Symptoms

Greater sleep difficulty following a challenging event, or a vulnerability to stress-related sleep disturbance (i.e., sleep reactivity), is characteristic of insomnia. However, insomnia is rarely observed in isolation; rather it is frequently seen in combination with other problems, such as depression. Despite the link between depression and increased sensitivity to stress, relatively little is known about the role sleep reactivity has in explaining variability in depressive symptoms. Therefore, the current study examined whether sleep reactivity was associated with depressive symptoms, and whether this relationship was mediated by insomnia. We assessed sleep reactivity, insomnia, and depressive symptoms among 2250 young adults (1244 female; M_age = 23.1, SD_age = 2.97) from the Colorado Longitudinal Twin Study and Community Twin Study. Results indicated that greater sleep reactivity was significantly associated with elevated depressive symptoms, and that this link was partially mediated by insomnia. This is one of the first studies to demonstrate an independent association between sleep reactivity and depressive symptomatology. These findings suggest that a greater sensitivity to stress-related sleep disturbance may also be a predisposing factor to depression, and highlight the need for a better understanding of sleep reactivity, as it may represent a more global vulnerability construct.

Stress-related sleep vulnerability and maladaptive sleep beliefs predict insomnia at long-term follow-up

INTRODUCTION

Vulnerability to stress-related sleep disturbances and maladaptive sleep beliefs has been proposed to be predisposing factors for insomnia. Yet previous studies addressing these factors have been cross-sectional in nature and could not be used to infer the time sequences of the association. The current study used a six-year follow-up to examine the predisposing roles of these two factors and their interactions with major life stressors in the development of insomnia.

METHODS

One hundred seventeen college students recruited for a survey in 2006 participated in this follow-up survey in 2012. In 2006, they completed a packet of questionnaires including the Dysfunctional Beliefs and Attitudes about Sleep Questionnaire, 10-item version (DBAS-10), the Ford Insomnia Response to Stress Test (FIRST), and the Pittsburgh Sleep Quality Index (PSQI); in 2012 they completed the Insomnia Severity Index (ISI) and the modified Life Experiences Survey (LES).

RESULTS

Fourteen of the participants were found to suffer from insomnia as measured by the ISI. Logistic regression showed that scores on both DBAS-10 and FIRST could predict insomnia at follow-up. When the interaction of DBAS-10 and LES and that of FIRST and LES were added, both DBAS-10 and FIRST remained significant predictors, while the interaction of FIRST and LES showed a near-significant trend in predicting insomnia.

CONCLUSIONS

The results showed that both vulnerability to stress-related sleep disturbances and maladaptive sleep beliefs are predisposing factors for insomnia. The hypothesized interaction effect between sleep vulnerability and major life stressors was found to be marginal. The maladaptive sleep beliefs, on the other hand, showed a predisposing effect independent from the influences of negative life events.

Stress and sleep reactivity: a prospective investigation of the stress-diathesis model of insomnia

STUDY OBJECTIVES

To prospectively assess sleep reactivity as a diathesis of insomnia, and to delineate the interaction between this diathesis and naturalistic stress in the development of insomnia among normal sleepers.

DESIGN

Longitudinal.

SETTING

Community-based.

PARTICIPANTS

2,316 adults from the Evolution of Pathways to Insomnia Cohort (EPIC) with no history of insomnia or depression (46.8 ± 13.2 y; 60% female).

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Participants reported the number of stressful events they encountered at baseline (Time 1), as well as the level of cognitive intrusion they experienced in response to each stressor. Stressful events (OR = 1.13; P < 0.01) and stress-induced cognitive intrusion (OR = 1.61; P < 0.01) were significant predictors of risk for insomnia one year hence (Time 2). Intrusion mediated the effects of stressful events on risk for insomnia (P < 0.05). Trait sleep reactivity significantly increased risk for insomnia (OR = 1.78; P < 0.01). Further, sleep reactivity moderated the effects of stress-induced intrusion (P < 0.05), such that the risk for insomnia as a function of intrusion was significantly higher in individuals with high sleep reactivity. Trait sleep reactivity also constituted a significant risk for depression (OR = 1.67; P < 0.01) two years later (Time 3). Insomnia at Time 2 significantly mediated this effect (P < 0.05).

CONCLUSIONS

This study suggests that premorbid sleep reactivity is a significant risk factor for incident insomnia, and that it triggers insomnia by exacerbating the effects of stress-induced intrusion. Sleep reactivity is also a precipitant of depression, as mediated by insomnia. These findings support the stress-diathesis model of insomnia, while highlighting sleep reactivity as an important diathesis.

CITATION

Drake CL, Pillai V, Roth T. Stress and sleep reactivity: a prospective investigation of the stress-diathesis model of insomnia.

Cognitive-emotional hyperarousal in the offspring of parents vulnerable to insomnia: a nuclear family study

Cognitive-emotional hyperarousal is believed to be a predisposing factor for insomnia; however, there is limited information on the association of familial vulnerability to insomnia and cognitive-emotional hyperarousal. The aim of this study was to estimate the heritability of stress-related insomnia and examine whether parental vulnerability to stress-related insomnia is associated with cognitive-emotional hyperarousal in their offspring. We studied a volunteer sample of 135 nuclear families comprised of 270 middle-aged (51.5 ± 5.4 years) fathers and mothers and one of their biological offspring (n = 135, 20.2 ± 1.1 years). We measured vulnerability to stress-related insomnia (i.e. Ford Insomnia Response to Stress Test: FIRST), perceived stress, depression and anxiety in all participants, and arousability, presleep cognitive and somatic arousal, coping and personality in the offspring. We found a heritability estimate of 29% for FIRST scores. High FIRST parents had three to seven times the odds of having offspring highly vulnerable to stress-related insomnia. Offspring of high FIRST parents showed higher arousability, presleep cognitive arousal and emotion-oriented coping. Furthermore, high FIRST mothers contributed to offspring's higher anxiety and lower task-oriented coping, while high FIRST fathers contributed to offspring's higher presleep somatic arousal and conscientiousness. Vulnerability to stress-related insomnia is significantly heritable. Parents vulnerable to stress-related insomnia have offspring with cognitive-emotional hyperarousal who rely upon emotion-oriented coping. These data give support to the notion that arousability and maladaptive coping are key factors in the aetiology of insomnia.

Prevalence of sleep disorders by sex and ethnicity among older adolescents and emerging adults: relations to daytime functioning, working memory and mental health

The study determined the prevalence of sleep disorders by ethnicity and sex, and related daytime functioning, working memory, and mental health among older adolescent to emerging adult college students. Participants were U.S.A. undergraduates (N = 1684), aged 17-25, recruited from 2010 to 2011. Participants completed online questionnaires for all variables. Overall, 36.0% of the sample screened positive for sleep disorders with insomnia, restless legs syndrome, and periodic limb movement disorder being the most prevalent. Women reported more insomnia and daytime impairment. African-Americans reported more early morning awakenings and less daytime impairment. Students with insomnia symptoms or restless legs syndrome tended to have lower working memory capacities. Students with nightmares or parasomnias had greater odds for mental disorders. In an older adolescent to emerging adult college student sample, sleep disorders may be a common source of sleep disturbance and impairment. Certain sleep disorders may be associated with lower working memory capacity and poor mental health.

Who is predisposed to insomnia: a review of familial aggregation, stress-reactivity, personality and coping style

Insomnia is a common health complaint world-wide. Insomnia is a risk factor in the development of other psychological and physiological disorders. Therefore understanding the mechanisms which predispose an individual to developing insomnia has great transdiagnostic value. However, whilst it is largely accepted that a vulnerable phenotype exists there is a lack of research which aims to systematically assess the make-up of this phenotype. This review outlines the research to-date, considering familial aggregation and the genetics and psychology of stress-reactivity. A model will be presented in which negative affect (neuroticism) and genetics (5HTTLPR) are argued to lead to disrupted sleep via an increase in stress-reactivity, and further that the interaction of these variables leads to an increase in learned negative associations, which further increase the likelihood of poor sleep and the development of insomnia.

Transient insomnia versus chronic insomnia: a comparison study of sleep-related psychological/behavioral characteristics

OBJECTIVES

Vulnerability to transient insomnia is regarded as a predisposing factor for chronic insomnia. However, most individuals with transient insomnia do not develop chronic insomnia. The current study investigated the differential contributing factors for these two conditions to further the understanding of this phenomenon.

METHOD

Chronic insomnia patients and normal sleepers with high and low vulnerability to transient insomnia completed measures of pre-sleep arousal, dysfunctional sleep beliefs, and sleep-related safety behaviors.

RESULTS

Both cognitive and somatic pre-sleep arousals were identified as significant predictors for transient insomnia. Dysfunctional beliefs regarding worry about insomnia and cognitive arousal were predictors for chronic insomnia. Sleep-related safety behavior, although correlated with insomnia severity, was not a significant predictor for both conditions.

CONCLUSIONS

Dysfunctional beliefs associated with worry and losing control over sleep are the most critical factors in differentiating chronic insomnia from transient insomnia. These factors should be addressed to help prevent individuals with high sleep vulnerability from developing chronic sleep disturbance.

Sleep reactivity and insomnia: genetic and environmental influences

STUDY OBJECTIVES

Determine the genetic and environmental contributions to sleep reactivity and insomnia.

DESIGN

Population-based twin cohort.

PARTICIPANTS

1782 individual twins (988 monozygotic or MZ; 1,086 dizygotic or DZ), including 744 complete twin pairs (377 MZ and 367 DZ). Mean age was 22.5 ± 2.8 years; gender distribution was 59% women.

MEASUREMENTS

Sleep reactivity was measured using the Ford Insomnia Response to Stress Test (FIRST). The criterion for insomnia was having difficulty falling asleep, staying asleep, or nonrefreshing sleep "usually or always" for ≥ 1 month, with at least "somewhat" interference with daily functioning.

RESULTS

The prevalence of insomnia was 21%. Heritability estimates for sleep reactivity were 29% for females and 43% for males. The environmental variance for sleep reactivity was greater for females and entirely due to nonshared effects. Insomnia was 43% to 55% heritable for males and females, respectively; the sex difference was not significant. The genetic variances in insomnia and FIRST scores were correlated (r = 0.54 in females, r = 0.64 in males), as were the environmental variances (r = 0.32 in females, r = 0.37 in males). In terms of individual insomnia symptoms, difficulty staying asleep (25% to 35%) and nonrefreshing sleep (34% to 35%) showed relatively more genetic influences than difficulty falling asleep (0%).

CONCLUSIONS

Sleep reactivity to stress has a substantial genetic component, as well as an environmental component. The finding that FIRST scores and insomnia symptoms share genetic influences is consistent with the hypothesis that sleep reactivity may be a genetic vulnerability for developing insomnia.

Cognitive-emotional hyperarousal as a premorbid characteristic of individuals vulnerable to insomnia

OBJECTIVE

To examine whether cognitive-emotional hyperarousal is a premorbid characteristic of middle-aged and young good sleepers vulnerable to stress-related insomnia.

METHODS

Self-reported information was collected from two samples of 305 middle-aged and 196 young adults. From those adults, 149 middle-aged (50.34 +/- 4.47 years) and 85 young (20.19 +/- 1.31 years) good sleepers were selected for the present study. The Ford Insomnia Response to Stress Test (FIRST) was used to measure vulnerability to stress-related insomnia. Trait measures of personality, arousability, rumination, presleep arousal, and coping skills were entered as predictors in the linear regression models, at the same time controlling for gender, depression, and anxiety.

RESULTS

The regression models showed that arousability (beta = 0.546), neuroticism (beta = 0.413), perceived stress (beta = 0.375), and rumination (beta = 0.214) were associated with FIRST scores in middle-aged adults. Among young adults, the regression models revealed that presleep cognitive arousal (beta = 0.448), arousability (beta = 0.426), neuroticism (beta = 0.320), presleep somatic arousal (beta = 0.290), emotion-oriented coping (beta = 0.220), and rumination (beta = 0.212) were associated with FIRST scores. Finally, individuals with high FIRST scores did not show lower scores in measures of cognitive-emotional hyperarousal compared with chronic insomniacs.

CONCLUSIONS

These data suggest that cognitive-emotional hyperarousal may be a premorbid characteristic of subjects vulnerable to insomnia. It seems that maladaptive coping stress strategies and cognitive-emotional hyperarousal predispose to the development of insomnia and that interventions targeting these characteristics may be important in the prevention and treatment of chronic insomnia.

Identifying sleep regulatory genes using a Drosophila model of insomnia

Although it is widely accepted that sleep must serve an essential biological function, little is known about molecules that underlie sleep regulation. Given that insomnia is a common sleep disorder that disrupts the ability to initiate and maintain restorative sleep, a better understanding of its molecular underpinning may provide crucial insights into sleep regulatory processes. Thus, we created a line of flies using laboratory selection that share traits with human insomnia. After 60 generations, insomnia-like (ins-l) flies sleep 60 min a day, exhibit difficulty initiating sleep, difficulty maintaining sleep, and show evidence of daytime cognitive impairment. ins-l flies are also hyperactive and hyperresponsive to environmental perturbations. In addition, they have difficulty maintaining their balance, have elevated levels of dopamine, are short-lived, and show increased levels of triglycerides, cholesterol, and free fatty acids. Although their core molecular clock remains intact, ins-l flies lose their ability to sleep when placed into constant darkness. Whole-genome profiling identified genes that are modified in ins-l flies. Among those differentially expressed transcripts, genes involved in metabolism, neuronal activity, and sensory perception constituted over-represented categories. We demonstrate that two of these genes are upregulated in human subjects after acute sleep deprivation. Together, these data indicate that the ins-l flies are a useful tool that can be used to identify molecules important for sleep regulation and may provide insights into both the causes and long-term consequences of insomnia.

The hyperarousal model of insomnia: a review of the concept and its evidence

Primary insomnia is defined as difficulties in falling asleep, maintaining sleep or non-restorative sleep accompanied by significantly impaired daytime functioning in the absence of a specific physical, mental or substance-related cause. The current review provides substantial support for the concept that hyperarousal processes from the molecular to the higher system level play a key role in the pathophysiology of primary insomnia. Autonomous, neuroendocrine, neuroimmunological, electrophysiological and neuroimaging studies demonstrate increased levels of arousal in primary insomnia during both night and daytime. In the light of neurobiological theories of sleep-wake regulation, primary insomnia may be conceptualized as a final common pathway resulting from the interplay between a genetic vulnerability for an imbalance between arousing and sleep-inducing brain activity, psychosocial/medical stressors and perpetuating mechanisms including dysfunctional sleep-related behavior, learned sleep preventing associations and other cognitive factors like tendency to worry/ruminate.

A community-based study of insomnia in Hong Kong Chinese children: Prevalence, risk factors and familial aggregation

OBJECTIVES

There has been limited data on familial aggregation of insomnia. We aimed to explore the prevalence, risk factors and familial aggregation of childhood insomnia with a large community-based sample.

METHODS

A community-based epidemiologic study of sleep disorders was conducted among primary school children. Those children with at least one reported biological parent were recruited. A total of 5695 children (mean age 9.2; SD 1.8), 4939 of their reported biological mothers (mean age 38.9; SD 4.6) and 4289 of their reported biological fathers (mean age 43.3; SD 5.5) were studied.

RESULTS

The rates of insomnia 3 times/week in the past 12 months were 4.0%, 12.8% and 9.7% for children, mothers and fathers, respectively. A robust familial aggregation of insomnia was found even after adjustment of the shared environmental and socio-demographic factors. There was a significant dose-response relationship among the children across their parental status from neither, fathers, mothers to both parents with insomnia [3.0%, 7.1%, 9.5% and 11.9%; with ORs (95% CIs)=2.48 (1.82-4.37) for fathers, 3.42 (2.55-4.59) for mothers and 4.42 (2.42-8.10) for both parents, respectively]. In addition, the frequency of insomniac symptoms of the parents also had a dose-response effect on the rate of insomnia of their children.

CONCLUSIONS

Insomnia is a common problem in both children and their parents. A significant familial aggregation of childhood onset insomnia was seen in this study even after adjustment of the co-risk factors. There was a dose-response effect of parental insomnia on the rate of insomnia of their children with a slight predilection of maternal influences.