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.

Daily Sleep-Stress Reactivity and Functional Impairment in World Trade Center Responders

BACKGROUND

How sleep is impacted by stress ("sleep reactivity to stress") and how stress is impacted by sleep ("stress reactivity to sleep") are trait-like characteristics of individuals that predict depression, anxiety, and insomnia. However, pathways between reactivity and functional impairment (e.g., impairment in social relationships and interpersonal functioning) have not been explored, which may be a critical pathway in understanding the link between reactivity and the development of psychological disorders.

PURPOSE

We examined associations between reactivity and changes in functional impairment among a cohort of 9/11 World Trade Center responders.

METHODS

Data from 452 responders (Mage = 55.22 years; 89.4% male) were collected between 2014 and 2016. Four baseline sleep and stress reactivity indices (i.e., sleep duration and efficiency reactivity to stress; stress reactivity to sleep duration and efficiency) were calculated from 14 days of sleep and stress data using random slopes from multilevel models. Functional impairment was assessed approximately 1 year and 2 years after baseline via semi-structured interviews. Latent change score analyses examined associations between baseline reactivity indices and changes in functional impairment.

RESULTS

Greater baseline sleep efficiency reactivity to stress was associated with decreases in functioning (β = -0.05, p = .039). In addition, greater stress reactivity to sleep duration (β = -0.08, p = .017) and sleep efficiency (β = -0.22, p < .001) was associated with lower functioning at timepoint one.

CONCLUSION

People who are more reactive to daily fluctuations in stress and sleep have poorer interpersonal relationships and social functioning. Identifying individuals with high reactivity who could benefit from preventative treatment may foster better social integration.

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.

Negative life stress, sleep disturbance, and depressive symptoms: The moderating role of anterior insula activity in response to sleep-related stimuli

BACKGROUND

This study investigated the effects of anterior insula (AI) activation on the association between stress and sleep disturbance as a neurobiological basis of the trait-like degree of sleep reactivity to stress. Additionally, it examined the effects of AI activity on the association between sleep disturbance and depression.

METHODS

The participants were 48 adults. To assess AI activation in response to sleep-related stimuli (SS) compared to neutral stimuli (NS), we extracted mean AI parameter estimates for the SS-NS contrast. We examined whether the interaction between life stress and AI activation would predict sleep disturbance and whether the interaction between sleep disturbance and AI activation would predict depression.

RESULTS

At higher levels of bilateral AI activation in response to SS, higher levels of stress were associated with greater sleep disturbance (left AI x stress: b = 1.07, SE = 0.44, p < 0.05; right AI x stress: b = 1.05, SE = 0.48, p < 0.05). In addition, at higher levels of right AI activation, higher levels of sleep disturbance were associated with more severe depressive symptoms (right AI x sleep disturbance: b = 2.55, SE = 1.10, p < 0.05).

LIMITATION

This study assessed sleep quality and depressive symptoms based on self-reported questionnaires.

CONCLUSION

This study revealed moderating effects of AI activation on the association between negative life stress and sleep disturbance. Additionally, AI activation strengthened the association between sleep disturbance and depression. AI activation may reflect a crucial etiological diathesis for insomnia and stress-related disorders.

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.

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.

Arousability as a trait predisposition to insomnia: multidimensional structure and clinical utility of the Spanish and English versions of the Arousal Predisposition Scale

OBJECTIVES

Traits related to a hyper-reactive arousal system (arousability) and weakened sleep system (sleep reactivity) are considered predisposing factors for insomnia of potential clinical utility. However, research examining the psychometric properties (ie, reliability and validity) of the Arousal Predisposition Scale (APS) and its clinical utility (ie, cut-off scores) among population-based and clinical samples is very limited.

METHODS

A total of 500 adults (41.8% female, 39.1 ± 15.9 years) from the general population in Spain and 217 adults (64.5% female, 46.0 ± 16.1 years) from a clinical sample in the United States completed the APS, as well as measures of sleep reactivity, insomnia severity, anxiety, depression, and stress. Structural equation modeling was used to conduct confirmatory factor analysis (CFA) of the APS. Correlation and receiver operating characteristic (ROC) analyses were used to determine convergent and predictive validity of the APS and its factors.

RESULTS

The CFAs supported two dimensions of emotional reactivity (APS-ER, 9 items) and trait anxiety (APS-TA, 3 items) in both independent samples. APS-ER was associated with sleep reactivity and performed better than APS-TA when predicting clinically significant sleep reactivity and similarly when predicting clinically significant insomnia severity.

CONCLUSIONS

Our findings support the specificity of emotional reactivity and sleep reactivity as trait predispositions to insomnia, while trait anxiety is a predisposing factor for the comorbidity of insomnia with state anxiety rather than a specific diathesis for insomnia. These data provide further support for the diathesis-stress model of insomnia and, as a transdiagnostic process, its potential etiological link with psychopathology.

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.

Stress-related sleep reactivity is associated with insomnia, psychopathology and suicidality in pregnant women: preliminary results

INTRODUCTION

Depression and anxiety symptoms are commonly experienced by women during pregnancy and may have negative consequences on mothers and newborns. Deterioration of sleep quality throughout pregnancy increases insomnia, which may lead to adverse outcomes including increased psychopathology in the perinatal period. Thus, identifying women at high risk of developing insomnia may have important clinical implications on maternal-fetal outcomes. Stress-related sleep reactivity is a well-established risk factor for future insomnia, depression, and anxiety in general adult samples. However, little is known of sleep reactivity and its relations to sleep and mood pathology in pregnancy. Therefore, we explored sleep reactivity in pregnant women and its relations to prenatal symptoms of insomnia, depression, anxiety, and suicidality.

METHOD

Sixty-two pregnant women (mean age 33.6 ± 3 years, 20.6 ± 0.6 weeks of pregnancy) were evaluated during their routine visit at the Gynecological Unit of the University of Pisa, Italy, using the Insomnia Severity Index (ISI) for insomnia symptoms, the Ford Insomnia Response to Stress Test for sleep reactivity (FIRST), Edinburgh Postnatal Depression Scale (EPDS) for depressive symptoms, and the Zung Self Rating Anxiety Scale (SAS) for anxiety symptoms. Item #10 of the EPDS was used to assess for suicidality. Differences in means between women with high vs low stress-related sleep reactivity were calculated using t-test or Mann-Whitney U/Wilcoxon test. Linear/multiple regression analyses have been performed to study associations between variables.

RESULTS

Pregnant women with high stress-related sleep reactivity, relative to those with low reactivity, reported greater symptoms of insomnia (t = 6.5, 0.004) as well as higher rates of depression (62.0% vs 6.1%, p < 0.001), anxiety (55.1% vs 15.1%, p = 0.030), and suicidality (17.2% vs 3.0%, p = 0.025). Multivariate models revealed sleep reactivity to correlate independently with symptoms of insomnia, depression, and anxiety, when controlling for comorbid symptoms.

CONCLUSIONS

In mid-pregnancy, women with high sleep reactivity report elevated symptoms of insomnia, depression, and anxiety, and are more likely to endorse suicidal ideation. As a prognostic marker of future insomnia and psychiatric illness, early detection of high prenatal sleep reactivity holds potential to prevent the development of sleep and mood pathology during pregnancy, thereby potentially improving maternal and child outcomes.

High-Frequency Heart Rate Variability Reactivity and Trait Worry Interact to Predict the Development of Sleep Disturbances in Response to a Naturalistic Stressor

BACKGROUND

High-frequency heart rate variability (HF-HRV) reactivity was proposed as a vulnerability factor for stress-induced sleep disturbances. Its effect may be amplified among individuals with high trait worry or sleep reactivity.

PURPOSE

This study evaluated whether HF-HRV reactivity to a worry induction, sleep reactivity, and trait worry predict increases in sleep disturbances in response to academic stress, a naturalistic stressor.

METHOD

A longitudinal study following 102 undergraduate students during an academic semester with well-defined periods of lower and higher academic stress was conducted. HF-HRV reactivity to a worry induction, trait worry using the Penn State Worry Questionnaire, and sleep reactivity using the Ford Insomnia Stress Reactivity Test were measured during the low stress period. Sleep disturbances using the Pittsburgh Sleep Quality Index were assessed twice during the lower stress period and three times during the higher stress period.

RESULTS

Greater reductions in HF-HRV in response to the worry induction predicted increases in sleep disturbances from the lower to the higher academic stress period. Trait worry moderated this association: individuals with both higher trait worry and greater HF-HRV reactivity to worry had larger increases in stress-related sleep disturbances over time, compared to participants with lower trait worry and HF-HRV reactivity. A similar, but marginally significant effect was found for sleep reactivity.

CONCLUSION

This study supports the role of HF-HRV reactivity as a vulnerability factor for stress-induced sleep disturbances. The combination of high trait worry and high HF-HRV reactivity to worry might identify a subgroup of individuals most vulnerable to stress-related sleep disturbances.

Investigating psychological and physiological responses to the Trier Social Stress Test in young adults with insomnia

OBJECTIVE

Stress and hyperarousal both contribute to insomnia. Elevated stress-related sleep reactivity is associated with hyperarousal, and might constitute a vulnerability to future insomnia. The present study examined acute stress-induced arousal and its association with nocturnal sleep.

METHODS

Participants were 30 healthy adults (66.7% female, M_age = 26.7 years): 10 with insomnia (INS) and 20 good sleepers with high vulnerability (HV) or low vulnerability (LV) to insomnia. They underwent two consecutive nights of polysomnography. During the evening preceding the second night, the Trier Social Stress Test (TSST) was administered, and psychological and physiological arousal indices were assessed.

RESULTS

The TSST elicited an increase in psychological and physiological arousal in all three groups. The INS group showed greater acute cortisol response (p < 0.05) and secretion at bedtime (p < 0.05), and higher pre-sleep cognitive arousal (p < 0.01) than the LV group; HV participants did not significantly differ from those in the INS or the LV group. Increased cortisol response and elevated sympathovagal imbalance (ie, low frequency/high frequency ratio) were each significantly associated with longer nocturnal awakenings (p = 0.048, p = 0.037, respectively). Heightened blood pressure was significantly associated with prolonged sleep onset latency, and reduced total sleep time and sleep efficiency (all ps < 0.05).

CONCLUSIONS

These findings support the hyperarousal conceptualization of insomnia and indirectly suggest that increased stress reactivity and bedtime hyperarousal might represent a trait-like vulnerability in certain good sleepers. More research is warranted to validate and expand these preliminary findings.

Sleep system sensitization: evidence for changing roles of etiological factors in insomnia

OBJECTIVES

To test for sensitization of the sleep system in response to insomnia development and major life stress. In addition, to evaluate the impact on depression and anxiety associated with sleep system sensitization.

METHODS

A longitudinal study with three annual assessments. The community-based sample included 262 adults with no history of insomnia or depression who developed insomnia one year after baseline (67.6% female; 44.0 ± 13.4 yr). Measures included the Ford Insomnia Response to Stress Test to assess sleep reactivity, Quick Inventory of Depressive Symptomatology, and Beck Anxiety Inventory. Insomnia classification was based on DSM-IV criteria. Sleep system sensitization was operationally defined as significant increases in sleep reactivity.

RESULTS

Sensitization of the sleep system was observed from baseline to insomnia onset at 1-yr follow-up among insomniacs with low premorbid vulnerability (p < 0.001), resulting in 68.3% of these individuals re-classified as highly sleep reactive. Major life stress was associated with greater sleep system sensitization (p = 0.02). Results showed that sleep reactivity at 2-yr follow-up remained elevated among those with low premorbid vulnerability, even after insomnia remission (p < 0.01). Finally, analyses revealed that increases in sleep reactivity predicted greater depression (p < 0.001) and anxiety (p < 0.001) at insomnia onset. The impact of sensitization on depression was stable at 2-yr follow-up (p = 0.01).

CONCLUSIONS

Evidence supports sensitization of the sleep system as a consequence of insomnia development and major life stress among individuals with low premorbid sleep reactivity. Sleep system sensitization may serve as a mechanism by which insomnia is perpetuated. Harmful effects of the sensitization process may increase risk for insomnia-related depression and anxiety.

Shift work disorder, depression, and anxiety in the transition to rotating shifts: the role of sleep reactivity

AIM

The aim of this study is to investigate premorbid sleep reactivity as a vulnerability to incident shift work disorder (SWD), and related changes in depression as well as anxiety following a transition to a rotating shifts work schedule.

METHODS

This is a longitudinal study with two waves of data collection. The community-based sample included normal sleeping non-shift workers (N = 96; 62.5% female; 47.9 ± 13.3 years) without a lifetime history of insomnia or baseline excessive daytime sleepiness who transitioned to rotating shift work one year later. Participants reported demographic characteristics, trait sleep reactivity on the Ford Insomnia Response to Stress Test, depression symptoms on the Quick Inventory of Depression Symptomatology, and anxiety symptoms on the Beck Anxiety Inventory. SWD was determined based on significant sleep disturbance and/or excessive sleepiness in the context of working in a rotating-shift schedule.

RESULTS

Analyses revealed that the odds were over five times greater for highly sleep-reactive individuals to develop SWD after transitioning to rotating shifts (OR = 5.59, p = 0.04). Nearly 90% of participants who suffered from SWD were accurately identified as high risk at one year before disease onset. Furthermore, individuals who developed SWD reported greater increases in symptoms of depression and anxiety. Finally, analyses revealed significant indirect effects wherein high sleep reactivity increased risk for SWD, which led to greater severity of anxiety and depression symptoms.

CONCLUSIONS

The Ford Insomnia Response to Stress Test (FIRST) accurately identifies a focused target population in which the premorbid psychobiological processes complicit in SWD onset and progression, as well as shift work-related depression and anxiety changes, can be better investigated, thus improving future preventative efforts.

Validation of the Japanese version of the Ford Insomnia Response to Stress Test and the association of sleep reactivity with trait anxiety and insomnia

OBJECTIVE

Our study was conducted to validate the Japanese version of the Ford Insomnia Response to Stress Test (FIRST-J) and to clarify the association of the measure with trait anxiety and insomnia in healthy subjects and insomnia patients.

METHODS

We studied 161 healthy subjects and 177 insomnia patients who completed the FIRST-J, Pittsburgh Sleep Quality Index (PSQI), Athens Insomnia Scale (AIS), and State-Trait Anxiety Inventory-Trait (STAI). The healthy subjects and the insomnia patients were classified, respectively, into two groups with high FIRST-J and low FIRST-J scores (divided by the median value of healthy subjects).

RESULTS

Cronbach α coefficients of the FIRST-J in the insomnia patients and healthy subjects were 0.89 and 0.87, respectively. Factor analysis revealed that the FIRST-J had a single-factor structure. The FIRST-J score significantly correlated with all other measures in the healthy subjects, though the score only correlated with the score of the STAI in the insomnia patients. The healthy subjects with high FIRST-J scores showed higher scores of the AIS and STAI than those with low FIRST-J scores. Furthermore, insomnia patients had a higher total score of the FIRST-J than the healthy subjects.

CONCLUSIONS

The FIRST-J is an important tool for assessing vulnerability to insomnia.