Sleep and PTSD in the Military Forces: A Reciprocal Relationship and a Psychiatric Approach

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.

Interest of neurofeedback training for cognitive performance and risk of brain disorders in the military context

Operational environments are characterized by a range of psycho-physiological constraints that can degrade combatants' performance and impact on their long-term health. Neurofeedback training (NFT), a non-invasive, safe and effective means of regulating brain activity, has been shown to be effective for mental disorders, as well as for cognitive and motor capacities and aiding sports performance in healthy individuals. Its value in helping soldiers in operational condition or suffering from post-traumatic stress (PTSD) is undeniable, but relatively unexplored. The aim of this narrative review is to show the applicability of NFT to enhance cognitive performance and to treat (or manage) PTSD symptoms in the military context. It provides an overview of NFT use cases before, during or after military operations, and in the treatment of soldiers suffering from PTSD. The position of NFT within the broad spectrum of performance enhancement techniques, as well as several key factors influencing the effectiveness of NFT are discussed. Finally, suggestions for the use of NFT in the military context (pre-training environments, and during and post-deployments to combat zones or field operations), future research directions, recommendations and caveats (e.g., on transfer to operational situations, inter-individual variability in responsiveness) are offered. This review is thus expected to draw clear perspectives for both researchers and armed forces regarding NFT for cognitive performance enhancement and PTSD treatment related to the military context.

REM disruption and REM vagal activity predict extinction recall in trauma-exposed individuals

BACKGROUND

Accumulating evidence suggests that rapid eye movement sleep (REM) supports the consolidation of extinction memory. REM is disrupted in posttraumatic stress disorder (PTSD), and REM abnormalities after traumatic events increase the risk of developing PTSD. Therefore, it was hypothesized that abnormal REM in trauma-exposed individuals may pave the way for PTSD by interfering with the processing of extinction memory. In addition, PTSD patients display reduced vagal activity. Vagal activity contributes to the strengthening of memories, including fear extinction memory, and recent studies show that the role of vagus in memory processing extends to memory consolidation during sleep. Therefore, it is plausible that reduced vagal activity during sleep in trauma-exposed individuals may be an additional mechanism that impairs extinction memory consolidation. However, to date, the contribution of sleep vagal activity to the consolidation of extinction memory or any emotional memory has not been investigated.

METHODS

Trauma-exposed individuals (n = 113) underwent a 2-day fear conditioning and extinction protocol. Conditioning and extinction learning phases were followed by extinction recall 24 h later. The association of extinction recall with REM characteristics and REM vagal activity (indexed as heart rate variability) during the intervening consolidation night was examined.

RESULTS

Consistent with our hypotheses, REM disruption was associated with poorer physiological and explicit extinction memory. Furthermore, higher vagal activity during REM was associated with better explicit extinction memory, and physiological extinction memory in males.

CONCLUSIONS

These findings support the notion that abnormal REM, including reduced REM vagal activity, may contribute to PTSD by impairing the consolidation of extinction memory.

The association between sleep disturbance and nightmares: Temporal dynamics of nightmare occurrence and sleep architecture in the home

We collected measures of sleep architecture and nightmares from participants (N = 61) wearing the DREEM 3 headband across 2 weeks of data collection to test the hypothesis that there are bidirectional links between insomnia (measured as sleep disturbance) and nightmare events. Nightmares were predicted by increased sleep disturbance the night before the nightmare, but not on the same night or 2 nights before. We also found that nightmare occurrences did not predict increased sleep disturbance on the same night or the following 2 nights, rather nightmares predicted increased sleep disturbance at the between-subjects level only. We suggest that nightmares are associated with an N3 sleep rebound on the night of the nightmare following a night of sleep disturbance.

REM disruption and REM Vagal Activity Predict Extinction Recall in Trauma-Exposed Individuals

Accumulating evidence suggests that rapid eye movement sleep (REM) supports the consolidation of extinction memory. REM is disrupted in PTSD, and REM abnormalities after traumatic events increase the risk of developing PTSD. Therefore, it was hypothesized that abnormal REM in trauma-exposed individuals may pave the way for PTSD by interfering with the processing of extinction memory. In addition, PTSD patients display reduced vagal activity. Vagal activity contributes to the strengthening of memories, including fear extinction memory, and recent studies show that the role of vagus in memory processing extends to memory consolidation during sleep. Therefore, it is plausible that reduced vagal activity during sleep in trauma-exposed individuals may be an additional mechanism that impairs extinction memory consolidation. However, to date, the contribution of sleep vagal activity to the consolidation of extinction memory or any emotional memory has not been investigated. To test these hypotheses, we examined the association of extinction memory with REM characteristics and REM vagal activity (indexed as heart rate variability) in a large sample of trauma-exposed individuals (n=113). Consistent with our hypotheses, REM disruption was associated with poorer physiological and explicit extinction memory. Furthermore, higher vagal activity during REM was associated with better explicit extinction memory, and physiological extinction memory in males. These findings support the notion that abnormal REM may contribute to PTSD by impairing the consolidation of extinction memory and indicate the potential utility of interventions that target REM sleep characteristics and REM vagal activity in fear-related disorders.

Evaluation of sleep and therapeutic education needs of military with PTSD

Sleep disorders in post-traumatic stress disorder (PTSD) are both diagnostic (nocturnal reliving) and prognostic. Poor sleep worsens the daytime symptomatology of PTSD and makes it resistant to treatment. However, no specific treatment is codified in France to treat these sleep disorders although sleep therapies (cognitive behavioural therapy for insomnia, psychoeducation and relaxation) have proven for years to be effective in treating insomnia. Therapeutic sessions can be part of a therapeutic patient education program, which is a model for the management of chronic pathologies. It allows for an improvement in a patient's quality of life and enhanced medication compliance. We therefore carried out an inventory of sleep disorders of patients with PTSD. First, we collected data by means of sleep diaries concerning the population's sleep disorders at home. Then we assessed the population's expectations and needs regarding its management of sleep, thanks to a semi-qualitative interview. The data from sleep diaries, which was consistent with the literature, showed that our patients suffered from severe sleep disorders that strongly impact their daily lives, with 87% of patients having an increased sleep onset latency, and 88% having nightmares. We observed a strong demand from patients for specific support for these symptoms, 91% expressing an interest in a TPE program targeting sleep disorders. Thanks to the data collected, the emerging themes for a future therapeutic patient education program targeting sleep disorders of soldiers with PTSD are: sleep hygiene; management of nocturnal awakenings, including nightmares; and psychotropic drugs.

The Effect of Concussion Mechanism of Injury on Sleep Problems in Active Duty Service Members Following Deployment

INTRODUCTION

Sleep disruption is pervasive in the military and is generally exacerbated during deployment, partially due to increases in operational tempo and exposure to stressors and/or trauma. In particular, sleep disruption is a commonly reported symptom following deployment-related traumatic brain injury (TBI), though less is known about the prevalence of sleep disturbance as a function of whether the TBI was induced by high-level blast (HLB) or direct impact to the head. TBI assessment, treatment, and prognosis are further complicated by comorbidity with posttraumatic stress disorder (PTSD), depression, and alcohol misuse. Here, we examine whether concussion mechanism of injury is associated with differences in the prevalence of self-reported sleep disturbance following deployment in a large sample of U.S. Marines while accounting for probable PTSD, depression, and alcohol misuse.

MATERIALS AND METHODS

This was a retrospective cohort study of active duty enlisted Marines with a probable concussion (N = 5757) who completed the Post-Deployment Health Assessment between 2008 and 2012. Probable concussion was defined as endorsement of a potentially concussive event with corresponding loss or alteration of consciousness. The presence of concussion-related sleep problems was assessed with a dichotomous item. Probable PTSD, depression, and alcohol misuse were assessed using the Primary Care PTSD Screen, the Patient Health Questionnaire-2, and the Alcohol Use Identification Test-Concise, respectively. Logistic regression models investigated the effects of mechanism of injury (HLB vs. impact), PTSD, depression, and alcohol misuse on the presence of sleep problems, adjusting for sex and pay grade. The study was approved by the Naval Health Research Center Institutional Review Board.

RESULTS

Approximately 41% of individuals with a probable deployment-related concussion reported sleep problems following the event; 79% of concussed individuals reporting both HLB and probable PTSD reported sleep problems. All main effects were significantly associated with sleep disturbance in adjusted models. PTSD showed the strongest association with sleep disturbance (adjusted odds ratio [AOR] = 2.84), followed by depression (AOR = 2.43), HLB exposure (AOR = 2.00), female sex (AOR = 1.63), alcohol misuse (AOR = 1.14), and pay grade (AOR = 1.10). A significant HLB × PTSD interaction emerged (AOR = 1.58), which suggests that sleep disturbance was elevated among those with both HLB-induced (vs. impact-induced) concussions and presence (vs. absence) of PTSD. No other significant interactions emerged.

CONCLUSION

To our knowledge, this is the first study to examine the prevalence of concussion-related sleep complaints following deployment as a function of the mechanism of injury in individuals with and without probable PTSD and depression. Individuals with HLB-induced concussion were twice as likely to report sleep problems as those with an impact-induced concussion. Future work should examine these effects longitudinally with validated measures that assess greater precision of exposure and outcome assessment (e.g., blast intensity and type of sleep disturbance).

Translation, Cross-Cultural Adaptation and Preliminary Validation of a French Version of the Trauma-Related Nightmare Survey (TRNS-FR) in a PTSD Veteran Population

INTRODUCTION

In the military population, trauma-related nightmares (TRNs) are highly associated with deployments and combat-related events. Trauma-related nightmares are also correlated with severity, treatment resistance, and chronicity of Post-Traumatic Stress Disorder (PTSD). However, to date, no specific measure of TRNs has been validated for use in the French language. This study aimed to translate and culturally adapt the English version of the Trauma-Related Nightmare Survey into French and to evaluate the psychometric properties of the translation on veterans.

MATERIALS AND METHODS

After the translation and cultural adaptation process, we evaluated the reliability and validity of the French version of the questionnaire (TRNS-FR) in a population of veterans suffering from PTSD with nightmare complaints (n = 56 patients for test-retest and n = 60 for internal consistency), recruited from five French military hospitals.

RESULTS

Analyses demonstrated that TRNS-FR has good test-retest reliability (r = 0.59) and good internal consistency with PTSD symptoms, insomnia symptoms, and subjective sleep parameters assessed at home. This questionnaire provides a rapid and comprehensive assessment of sleep disturbance and a specific description of TRNs in the population of veterans with severe PTSD. Our results allowed us to propose a valid and reliable French adaptation of the questionnaire.

CONCLUSION

Because sleep disturbances and TRNs require specific therapeutic management, the psychometric qualities of TRNS-FR make it a tool of choice for assessing TRNs in future clinical research settings.

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 Disturbances in Panic Disorder with Comorbid Complex PTSD: A Possible Relationship and Different Psychopathology?

BACKGROUND

Several studies have shown the possible link between trauma and sleep disturbances, particularly in anxiety disorders. This issue could be because sympathetic hyperarousal is central to both disorders, probably caused by a dysregulation of the noradrenergic system. This study aimed to establish if the comorbidity with complex post-traumatic stress disorder (cPTSD) is associated with sleep disturbances in panic disorder (PD) and if the presence of poor sleep quality is associated with a higher psychopathological burden.

METHODS

Participants (N = 211) with PD completed the International Trauma Questionnaire concerning their most troubling experience, the Hamilton Anxiety Rating Scale (HAM-A), and the Pittsburgh Sleep Quality Index (PSQI) to assess anxiety symptoms and sleep disturbances, respectively.

RESULTS

The sample was divided into two subgroups based on the presence of cPTSD. No significant differences emerged in the bivariate analyses for what concerns sociodemographic features. As for the scores of the psychopathological scales, the analysis highlighted statistically significant differences between the subgroups. Subjects with cPTSD reported significantly higher HAM-A total scores. As for the disturbances in self-organization (DSO) and PSQI scores, these were all significantly higher in the cPTSD subsample. At the logistic regression, the presence of cPTSD was inserted as the dependent variable, while the PSQI scores of the subscales evaluating subjective sleep quality, sleep duration, sleep efficacy, and the use of hypnotics were used as independent variables. The presence of cPTSD was significantly associated with the PSQI subscores for subjective sleep quality and use of hypnotics.

CONCLUSIONS

Patients with PD exhibit more severe sleep disturbances and a higher anxiety burden when experiencing prolonged trauma. Therapeutic advances are needed in this field to target these symptomatologic domains.

An ecological approach to clinically assess nightmares in military service members with severe PTSD

BACKGROUND

Trauma-related nightmares (TRNs) are distressing events which contribute to insomnia severity, chronicity and treatment resistance of PTSD. Therefore, recording TRNs is a crucial technical challenge in order to understand their physiopathological patterns and their impact on sleep. However, TRNs are difficult to record during a single night in a sleep laboratory, which, moreover, is likely to be considered by patients as a protective sleep environment that is therefore not representative of home sleep conditions.

METHOD

In the present study, we investigate if objective sleep measures acquired at-home using two ambulatory devices is of clinical value by correlating with PTSD patients' complaints about sleep and nightmares. A secondary objective is to relate awakenings associated with TRNs to sleep stages and to provide new insights into the use of electrodermal activity (EDA) as a potential physiological marker of TRNs. Sixty veterans and active-duty service members were assessed by questionnaires and recorded for 5 consecutive nights in their homes.

RESULTS

Our approach firstly identified positive correlations between subjective and objective sleep parameters (total sleep time, sleep-onset latency and TRNs frequency). We also developed a method of synchronization between the two ambulatory devices that allowed us to match 200 TRNs (reported by event marker push button) with sleep stages corresponding to 91 nights and 37 patients. Most awakenings associated with TRNs occurred during NREM sleep (65.5% versus 34.5% during REM sleep). Our results also reveal significant differences in the frequency of EDA peaks 10 min before the reported events, with a lower frequency in REM (13.7 peaks) than in NREM (24.8 peaks) awakenings associated with TRNs. This EDA peaks frequency in REM sleep is not statistically different from that in REM sleep preceding awakenings that are not associated with TRNs.

CONCLUSION

The development of wearable devices to collect physiological parameters is of interest in clinical practice to improve our knowledge of sleep and trauma-related nightmares in patients with PTSD.

Nanowired Delivery of Cerebrolysin Together with Antibodies to Amyloid Beta Peptide, Phosphorylated Tau, and Tumor Necrosis Factor Alpha Induces Superior Neuroprotection in Alzheimer's Disease Brain Pathology Exacerbated by Sleep Deprivation

Sleep deprivation induces amyloid beta peptide and phosphorylated tau deposits in the brain and cerebrospinal fluid together with altered serotonin metabolism. Thus, it is likely that sleep deprivation is one of the predisposing factors in precipitating Alzheimer's disease (AD) brain pathology. Our previous studies indicate significant brain pathology following sleep deprivation or AD. Keeping these views in consideration in this review, nanodelivery of monoclonal antibodies to amyloid beta peptide (AβP), phosphorylated tau (p-tau), and tumor necrosis factor alpha (TNF-α) in sleep deprivation-induced AD is discussed based on our own investigations. Our results suggest that nanowired delivery of monoclonal antibodies to AβP with p-tau and TNF-α induces superior neuroprotection in AD caused by sleep deprivation, not reported earlier.

Pre-deployment threat learning predicts increased risk for post-deployment insomnia: Evidence from the Marine Resiliency Study

Insomnia is a common and impairing consequence of military deployment, but little is known about pre-deployment risk factors for post-deployment insomnia. Abnormal threat learning tendencies are commonly observed in individuals with insomnia and maladaptive responses to stress have been implicated in the development of insomnia, suggesting that threat learning could be an important risk factor for post-deployment insomnia. Here, we examined pre-deployment threat learning as a predictor of post-deployment insomnia and the potential mechanisms underlying this effect. Male servicemembers (N = 814) completed measures of insomnia, psychiatric symptoms, and a threat learning task before and after military deployment. Threat learning indices that differentiated participants with versus withoutinsomnia at post-deployment were tested as pre-deployment predictors of post-deployment insomnia. Post-deployment insomnia was linked to elevations on several threat learning indices at post-deployment, but only higher threat conditioning, as indexed by higher threat expectancy ratings to the danger cue, emerged as a pre-deployment predictor of post-deployment insomnia. This effect was independent of combat exposure levels and partially mediated by greater post-deployment nightmares. The tendency to acquire stronger expectations of aversive events following encounters with danger cues may increase risk for post-deployment insomnia, in part due to the development of more severe nightmares.

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

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