Sleep disturbance at pre-deployment is a significant predictor of post-deployment re-experiencing symptoms

Stress-induced increase in heart-rate during sleep as an indicator of PTSD risk among combat soldiers

STUDY OBJECTIVES

Discerning the differential contribution of sleep behavior and sleep physiology to the subsequent development of posttraumatic-stress-disorder (PTSD) symptoms following military operational service among combat soldiers.

METHODS

Longitudinal design with three measurement time points: during basic training week (T1), during intensive stressed training week (T2), and following military operational service (T3). Participating soldiers were all from the same unit, ensuring equivalent training schedules and stress exposures. During measurement weeks soldiers completed the Depression Anxiety and Stress Scale (DASS) and the PTSD Checklist for DSM-5 (PCL-5). Sleep physiology (sleep heart-rate) and sleep behavior (duration, efficiency) were monitored continuously in natural settings during T1 and T2 weeks using wearable sensors.

RESULTS

Repeated measures ANOVA revealed a progressive increase in PCL-5 scores from T1 and T2 to T3, suggesting an escalation in PTSD symptom severity following operational service. Hierarchical linear regression analysis uncovered a significant relation between the change in DASS stress scores from T1 to T2 and subsequent PCL-5 scores at T3. Incorporating participants' sleep heart-rate markedly enhanced the predictive accuracy of the model, with increased sleep heart-rate from T1 to T2 emerging as a significant predictor of elevated PTSD symptoms at T3, above and beyond the contribution of DASS stress scores. Sleep behavior did not add to the accuracy of the model.

CONCLUSION

Findings underscore the critical role of sleep physiology, specifically elevated sleep heart-rate following stressful military training, in indicating subsequent PTSD risk following operational service among combat soldiers. These findings may contribute to PTSD prediction and prevention efforts.

Symptoms of Posttraumatic Stress Disorder Among Japanese Peacekeepers Deployed in South Sudan

Importance

Peacekeepers in United Nations missions experience potentially traumatic events, resulting in increased risk for posttraumatic stress disorder (PTSD). Understanding the course and risk factors of PTSD symptom severity is crucial to ensure personnel safety.

Objective

To investigate the incidence of PTSD, symptom severity trajectories, and potential risk factors associated with adverse trajectories among Japanese peacekeepers deployed in South Sudan.

Design, Setting, and Participants

Data for this 6-year prospective cohort study were collected from December 2011 to December 2018 from Japan Ground Self-Defense Force personnel deployed at the United Nations Mission in South Sudan, corresponding to before and up to 78 months after deployment. Of 3799 potential participants, 80 were excluded because of multiple deployments and 757 because of missing data, incomplete responses, or not providing informed consent. Therefore, 2962 participants were included in the analysis. Data analysis was performed from February 2022 to February 2024.

Exposure

The participants were deployed to United Nations Mission in South Sudan for 6 months.

Main Outcomes and Measures

The 22-item Impact of Event Scale-Revised was used to assess PTSD symptoms, with 25 or more points indicating probable PTSD (p-PTSD). Sociodemographic data were collected, and the 30-item General Health Questionnaire was administered before deployment to identify risk factors for PTSD symptom severity.

Results

In the 2962 participants studied (2901 [97.9%] male; mean [SD] age, 33.9 [7.2] years), the incidence of p-PTSD was 3.95%. Latent growth mixture models identified 4 symptom severity trajectories: resilient (2143 [72.3%]), recovery (479 [16.2%]), protracted (182 [6.1%]), and delayed (158 [5.3%]). Multinomial logistic regression showed that sleep disturbance was a common risk factor for the 2 most severe trajectories (protracted: odds ratio [OR], 1.29; 95% CI, 1.08-1.54; delayed: OR, 1.26; 95% CI, 1.03-1.53), whereas older age (OR, 1.25; 95% CI, 1.06-1.48), anxiety and dysphoria (OR, 1.45; 95% CI, 1.20-1.75), and general illness (OR, 1.30; 95% CI, 1.06-1.59) were associated with the protracted trajectory.

Conclusions and Relevance

This cohort study found that approximately 4% of the participants developed p-PTSD and identified 4 distinct PTSD symptom trajectories. The findings suggest that addressing sleep disturbance and general health issues could effectively prevent PTSD symptoms among peacekeepers.

From childhood adversity to latent stress vulnerability in adulthood: the mediating roles of sleep disturbances and HPA axis dysfunction

Childhood adversity is a prominent predisposing risk factor for latent stress vulnerability, expressed as an elevated likelihood of developing stress-related psychopathology upon subsequent exposure to trauma in adulthood. Sleep disturbances have emerged as one of the most pronounced maladaptive behavioral outcomes of childhood adversity and are also a highly prevalent core feature of stress-related psychopathology, including post-traumatic stress disorder (PTSD). After reviewing the extensive literature supporting these claims, the current review addresses the notion that childhood adversity-induced sleep disturbances may play a causal role in elevating individuals' stress vulnerability in adulthood. Corroborating this, sleep disturbances that predate adult trauma exposure have been associated with an increased likelihood of developing stress-related psychopathology post-exposure. Furthermore, novel empirical evidence suggests that sleep disturbances, including irregularity of the sleep-wake cycle, mediate the link between childhood adversity and stress vulnerability in adulthood. We also discuss cognitive and behavioral mechanisms through which such a cascade may evolve, highlighting the putative role of impaired memory consolidation and fear extinction. Next, we present evidence to support the contribution of the hypothalamic-pituitary-adrenal (HPA) axis to these associations, stemming from its critical role in stress and sleep regulatory pathways. Childhood adversity may yield bi-directional effects within the HPA stress and sleep axes in which sleep disturbances and HPA axis dysfunction reinforce each other, leading to elevated stress vulnerability. To conclude, we postulate a conceptual path model from childhood adversity to latent stress vulnerability in adulthood and discuss the potential clinical implications of these notions, while highlighting directions for future research.

Sleep and mental health in recruit paramedics: a 6-month longitudinal study

STUDY OBJECTIVES

To explore potential relationships and longitudinal changes in sleep and mental health in recruit paramedics over the first 6 months of work, and whether sleep disturbances pre-emergency work predict future mental health outcomes.

METHODS

Participants (N = 101, 52% female, Mage = 26 years) completed questionnaires prior to (baseline), and after 6 months of emergency work to assess for symptoms of insomnia, obstructive sleep apnea, post-traumatic stress disorder (PTSD), depression, anxiety, and trauma exposure. At each timepoint, participants also completed a sleep diary and wore an actigraph for 14 days to assess sleep patterns. Correlations between baseline sleep and mental health were conducted and changes in these variables across timepoints were examined using linear mixed models. Hierarchical regressions assessed whether sleep at baseline predicted mental health at follow-up.

RESULTS

Insomnia and depression symptoms, and total sleep time increased while sleep onset latency decreased across the first 6 months of emergency work. Participants experienced an average of 1 potentially traumatic event during the 6-month period. Baseline insomnia predicted increased depression symptoms at the 6-month follow-up, while baseline wake after sleep onset predicted follow-up PTSD symptoms.

CONCLUSION

Results highlight an increase in insomnia and depression across the initial months of emergency work, while sleep disturbances before emergency work were identified as potential risk factors for the development of depression and PTSD among paramedics in their early career. Screening and early interventions targeting poor sleep at the beginning of emergency employment may assist in reducing the risk of future mental health outcomes in this high-risk occupation.

Sleep Quality Disturbances Are Associated with White Matter Alterations in Veterans with Post-Traumatic Stress Disorder and Mild Traumatic Brain Injury

Sleep disturbances are strongly associated with mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD). PTSD and mTBI have been linked to alterations in white matter (WM) microstructure, but whether poor sleep quality has a compounding effect on WM remains largely unknown. We evaluated sleep and diffusion magnetic resonance imaging (dMRI) data from 180 male post-9/11 veterans diagnosed with (1) PTSD (n = 38), (2) mTBI (n = 25), (3) comorbid PTSD+mTBI (n = 94), and (4) a control group with neither PTSD nor mTBI (n = 23). We compared sleep quality (Pittsburgh Sleep Quality Index, PSQI) between groups using ANCOVAs and calculated regression and mediation models to assess associations between PTSD, mTBI, sleep quality, and WM. Veterans with PTSD and comorbid PTSD+mTBI reported poorer sleep quality than those with mTBI or no history of PTSD or mTBI (p = 0.012 to <0.001). Poor sleep quality was associated with abnormal WM microstructure in veterans with comorbid PTSD+mTBI (p < 0.001). Most importantly, poor sleep quality fully mediated the association between greater PTSD symptom severity and impaired WM microstructure (p < 0.001). Our findings highlight the significant impact of sleep disturbances on brain health in veterans with PTSD+mTBI, calling for sleep-targeted interventions.

The association of polysomnographic sleep on posttraumatic stress disorder symptom clusters in trauma-exposed civilians and veterans

Study Objectives

Self-reported sleep disturbance has been established as a risk factor and predictor for posttraumatic stress disorder (PTSD); however, less is known about the relationship between objective sleep and PTSD symptom clusters, and the specific role of hyperarousal. The present study examined the relationships between sleep continuity and architecture on PTSD symptom clusters.

Methods

Participants underwent two in-laboratory sleep studies to assess sleep continuity and architecture. They also completed the Clinician-Administered PTSD-IV scale and the Structured Clinical Interview for the DSM-IV to assess for PTSD diagnosis and other psychiatric disorders.

Results

Sleep continuity (i.e. total sleep time, sleep efficiency percent, wake after sleep onset, sleep latency) was significantly related to PTSD Cluster B (reexperiencing) symptom severity (R ² = .27, p < .001). Sleep architecture, specifically Stage N1 sleep, was significantly associated with PTSD Cluster B (t = 2.98, p = .004), C (Avoidance; t = 3.11, p = .003), and D (Hyperarosual; t = 3.79, p < .001) symptom severity independently of Stages N2, N3, and REM sleep. REM sleep variables (i.e. REM latency, number of REM periods) significantly predicted Cluster D symptoms (R ² = .17, p = .002).

Conclusions

These data provide evidence for a relationship between objective sleep and PTSD clusters, showing that processes active during Stage N1 sleep may contribute to PTSD symptomatology in civilians and veterans. Further, these data suggest that arousal mechanisms active during REM sleep may also contribute to PTSD hyperarousal symptoms.This paper is part of the War, Trauma, and Sleep Across the Lifespan Collection. This collection is sponsored by the Sleep Research Society.

Effects of Sleep Deficiency on Risk, Course, and Treatment of Psychopathology

This article reviews the literature on the relationship between sleep deficiency and unipolar and bipolar depression, anxiety disorders, and posttraumatic stress disorder. We consider the evidence for sleep as a contributory causal factor in the development of psychiatric disorders, as well as sleep as an influential factor related to the outcome and recurrence of psychopathology. A case for sleep deficiency being an important treatment target when sleep and psychiatric disorders are comorbid is also made. Our recommendation is that sleep deficiency is recognized as a means to positively impact the development and course of psychopathology and, as such, is routinely assessed and treated in clinical practice.

Moderators of Cognitive Behavioral Treatment for Insomnia on Depression and Anxiety Outcomes

PURPOSE OF REVIEW

With a focus on reviewing adequately powered randomized controlled trials, we present recent research on the potential of cognitive behavioral therapy for insomnia (CBT-I) to improve depression and anxiety outcomes among patients with insomnia and one of the following comorbid psychiatric disorders: major depressive disorder (MDD), generalized anxiety disorder (GAD), or posttraumatic stress disorder (PTSD). We also examine potential moderators of CBT-I on depression and anxiety outcomes in this population.

RECENT FINDINGS

Despite high comorbidity rates, current behavioral and pharmacological treatments for MDD, GAD, and PTSD do not substantially target or improve insomnia symptoms; residual insomnia is exceedingly common even among patients who experience remission. Insomnia plays a critical role in the onset and maintenance of depression and anxiety, and treating insomnia with CBT-I may improve global outcomes for patients with MDD, GAD, and PTSD. CBT-I is superior to traditional depression/anxiety treatment in improving insomnia symptoms among patients with comorbid psychiatric disorders. Results are mixed on whether CBT-I (either alone or augmented with depression/anxiety treatment) is effective in improving overall MDD, GAD, and PTSD outcomes. Evening circadian preference and depression/anxiety symptom severity may moderate the effect of CBT-I on depression and anxiety outcomes.

Prospective examination of pre-trauma anhedonia as a risk factor for post-traumatic stress symptoms

BACKGROUND

Anhedonia, the reduction of pleasure and reward-seeking behaviour, is a transdiagnostic symptom with well-described neural circuit mediators. Although typically observed during disease state, extant hypotheses suggest that anhedonia may also be an early risk factor for development of psychopathology. Understanding the contribution of anhedonia to the trauma-response trajectory may bolster inferences about biological mechanisms contributing to pre-trauma risk versus trauma-related symptom expression, knowledge of which could aid in targeted interventions.

OBJECTIVE

Using a prospective, longitudinal design in a population at risk for trauma disorders, we tested the hypothesis that anhedonia may be a pre-trauma risk factor for post-traumatic stress disorder (PTSD) symptoms.

METHODS

Adult male participants from the Marine Resilience Study (N = 2,593) were assessed across three time-points (pre-deployment, 3-month and 6-month post-deployment). An anhedonia factor was extracted from self-report instruments pre-trauma and tested for its relationship with development of PTSD re-experiencing symptoms after deployment.

RESULTS

Higher pre-deployment anhedonia predicted increased PTSD intrusive re-experiencing symptoms at 3- and 6-months post-deployment when controlling for pre-trauma PTSD and depression symptoms. Depression symptoms were not significant predictors of subsequent PTSD intrusive re-experiencing symptoms. Anhedonia at 3 mo also robustly predicted maintenance of PTSD intrusive re-experiencing symptoms at the 6 mo time point.

CONCLUSIONS

Pre-deployment anhedonia may be a pre-trauma risk factor for PTSD, not simply a state-dependent effect of trauma exposure and PTSD symptom expression. Anhedonia may contribute to persistence and/or chronicity of re-experiencing symptoms after the emergence of PTSD symptoms.

Prenatal insomnia and childbirth-related PTSD symptoms: A prospective population-based cohort study

BACKGROUND

Certain populations are at high risk of experiencing a traumatic event and developing post-traumatic stress disorder (PTSD). Yet, primary preventive interventions against PTSD are lacking. It is therefore crucial to identify pre-traumatic risk factors, which could be targeted with such interventions. Insomnia may be a good candidate, but studies on civilians are sparse. Furthermore, the mechanisms at stake in the relationship between pre-traumatic insomnia and PTSD symptoms are unclear.

METHODS

This prospective population-based cohort study (n = 1,610) examined the relationship between insomnia symptoms at 32 weeks of pregnancy and childbirth-related PTSD (CB-PTSD) symptoms at eight weeks postpartum. Postnatal insomnia symptoms, prenatal psychological symptoms (depression, anxiety, PTSD, fear of childbirth), subjective birth experience (SBE) and birth medical severity were included as covariates in the analyses, which were based on a Piecewise Structural Equation Modelling approach.

RESULTS

The relationship between prenatal insomnia and CB-PTSD symptoms was mediated by negative SBE and postnatal insomnia symptoms. All relationships involving insomnia symptoms had small or very small effect sizes.

LIMITATIONS

This study used self-report questionnaires. Postnatal insomnia and CB-PTSD symptoms were concurrently measured.

CONCLUSION

Prenatal insomnia symptoms may impair the ability to cope with a difficult birth experience and contribute to postnatal insomnia, a risk factor for CB-PTSD. Thus, prenatal insomnia symptoms may be a promising target for CB-PTSD primary preventive interventions, although other prenatal psychological symptoms could also be considered. Even beyond the perinatal context, future studies on pre-traumatic insomnia and PTSD should include post-traumatic insomnia as a covariate.

Postmigration stress and sleep disturbances mediate the relationship between trauma exposure and posttraumatic stress symptoms among Syrian and Iraqi refugees

STUDY OBJECTIVES

Sleep disturbance is common in those who experience trauma. In a sample of nontreatment-seeking refugees, we examined the associations between trauma exposure, postmigration stress, sleep symptoms, and posttraumatic psychological symptoms.

METHODS

Syrian and Iraqi refugees (n = 86; 51% female; mean age = 45 years) residing in Australia were recruited from the local community. Cross-sectional descriptive design, multinominal regression analyses, and mediation analyses were used. Participants completed measures in Arabic assessing premigration trauma exposure, postmigration stress, sleep symptoms, and mental health. They also completed 7 days of sleep diaries and actigraphy.

RESULTS

We identified 34.9% of the participants as normal sleepers, 32.6% as probably having insomnia, and 32.6% as likely having insomnia. Variables associated with greater sleep disturbance (McFadden's R² = 0.57) included greater trauma exposure, increased time of resettlement, greater postmigration stress, and greater presleep arousal. The association of premigration trauma exposure to current posttraumatic symptoms was mediated sequentially by postmigration stress and sleep symptoms.

CONCLUSIONS

Our findings highlight the extent of sleep disturbance in refugees. We found evidence for an indirect pathway between trauma exposure and posttraumatic symptoms through premigration stress and sleep (particularly presleep arousal). In the current global refugee crisis, improving the existing system of care in countries experiencing increased migration is critical. Because sleep disturbance is a modifiable condition associated with mental health, targeting sleep could be an important component of psychological interventions for refugees.

Go to Bed and You MIGHT Feel Better in the Morning—the Effect of Sleep on Affective Tone and Intrusiveness of Emotional Memories

Purpose of Review

It is important to examine what effect sleep has after an emotional experience. More knowledge about this topic could help inform us whether there are any potential sleep interventions that could help make sure that memories of negative emotional experiences are processed in the most adaptive manner possible.

Recent Findings

Findings on the role of sleep in altering reactivity to emotional stimuli have been highly varied, with significant findings in opposite directions. A new exciting development in the field is several studies finding that sleep seems to make memories of negative experiences less intrusive.

Summary

This review has mainly aimed to give an overview of the field, and of which issues need to be resolved. We argue for there being a strong need for standardization of how data are analyzed and presented, as well as for better methods for determining to what extent the effects of sleep are specific for a particular memory, or represent general changes in emotional reactivity.

Sleep, circadian system and traumatic stress

The human circadian system creates and maintains cellular and systemic rhythmicity essential for the temporal organization of physiological processes promoting homeostasis and environmental adaptation. Sleep disruption and loss of circadian rhythmicity fundamentally affects master homeostasic regulating systems at the crossroads of peripheral and central susceptibility pathways, similar to acute or chronic stress and, thus, may play a central role in the development of stress-related disorders. Direct and indirect human and animal PTSD research accordingly suggests circadian-system-linked sleep, neuroendocrine, immune, metabolic and autonomic dysregulation, linking circadian misalignment to PTSD pathophysiology. Additionally, there is evidence that sleep and circadian disruption may represent a vital pre-existing risk factor in the prediction of PTSD development, while sleep-related symptoms are among the most prominent in trauma-associated disorders. These facts may represent a need for a shift towards a more chronobiological understanding of traumatic sequel and could support better prevention, evaluation and treatment of sleep and circadian disruption as first steps in PTSD management. In this special issue, we highlight and review recent advances from human sleep and chronobiological research that enhances our understanding of the development and maintenance of trauma-related disorders.

Cortisol awakening response over the course of humanitarian aid deployment: a prospective cohort study

Background: Internationally deployed humanitarian aid (HA) workers are routinely confronted with potentially traumatic stressors. However, it remains unknown whether HA deployment and related traumatic stress are associated with long-term changes in hypothalamic-pituitary-adrenal (HPA) axis function. Therefore, we investigated whether cortisol awakening response (CAR) decreased upon deployment and whether this was moderated by previous and recent trauma exposure and parallel changes in symptom severity and perceived social support. Methods: In this prospective study, n = 86 HA workers (68% females) completed questionnaires regarding trauma exposure, posttraumatic stress disorder (PTSD), anxiety and depressive symptoms and perceived social support, as well as salivary cortisol assessments at awakening and 30 minutes post-awakening at before, early and 3-6 months post-deployment. Results: Linear mixed models showed significantly decreased CAR (b(SE) = -.036(.011), p = .002) and awakening cortisol over time (b(SE) = -.007(.003), p = .014). The extent of awakening cortisol change was significantly moderated by interactions between previous and recent trauma exposure. Also, a steeper awakening cortisol decrease was significantly associated with higher mean anxiety and PTSD symptoms across assessments. No significant effects were found for social support. Conclusions: We observed attenuated CAR and awakening cortisol upon HA deployment, with a dose-response effect between trauma exposure before and during the recent deployment on awakening cortisol. Awakening cortisol change was associated with PTSD and anxiety symptom levels across assessments. Our findings support the need for organizational awareness that work-related exposures may have long-lasting biological effects. Further research assessing symptoms and biological measures in parallel is needed to translate current findings into guidelines on the individual level.

Traumatic stress and the circadian system: neurobiology, timing and treatment of posttraumatic chronodisruption

Background: Humans have an evolutionary need for a well-preserved internal 'clock', adjusted to the 24-hour rotation period of our planet. This intrinsic circadian timing system enables the temporal organization of numerous physiologic processes, from gene expression to behaviour. The human circadian system is tightly and bidirectionally interconnected to the human stress system, as both systems regulate each other's activity along the anticipated diurnal challenges. The understanding of the temporal relationship between stressors and stress responses is critical in the molecular pathophysiology of stress-and trauma-related diseases, such as posttraumatic stress disorder (PTSD). Objectives/Methods: In this narrative review, we present the functional components of the stress and circadian system and their multilevel interactions and discuss how traumatic stress can affect the harmonious interplay between the two systems. Results: Circadian dysregulation after trauma exposure (posttraumatic chronodisruption) may represent a core feature of trauma-related disorders mediating enduring neurobiological correlates of traumatic stress through a loss of the temporal order at different organizational levels. Posttraumatic chronodisruption may, thus, affect fundamental properties of neuroendocrine, immune and autonomic systems, leading to a breakdown of biobehavioral adaptive mechanisms with increased stress sensitivity and vulnerability. Given that many traumatic events occur in the late evening or night hours, we also describe how the time of day of trauma exposure can differentially affect the stress system and, finally, discuss potential chronotherapeutic interventions. Conclusion: Understanding the stress-related mechanisms susceptible to chronodisruption and their role in PTSD could deliver new insights into stress pathophysiology, provide better psychochronobiological treatment alternatives and enhance preventive strategies in stress-exposed populations.

Sleep disturbance and psychiatric disorders

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