Preventing sleep on the first resting phase following a traumatic event attenuates anxiety-related responses

Effect of sleep manipulations on intrusive memories after exposure to an experimental analogue trauma: A meta-analytic review

Sleep plays an important role in memory processing and is disrupted in individuals with post-traumatic stress disorder (PTSD). A growing body of research has experimentally investigated how sleep - or lack thereof - in the early aftermath of a traumatic experience contributes to intrusive memory formation. The aim of this meta-analytic review was to examine the effects of various experimental sleep manipulations (e.g., sleep deprivation, daytime naps) on intrusive memories following exposure to an experimentally induced analogue traumatic event. Eight eligible studies were systematically identified through PsycInfo and PubMed and provided sufficient data to contribute to a meta-analysis of the effects of sleep versus wakefulness on intrusive memory frequency. Sleep was found to reduce intrusive memory frequency when compared to wakefulness at a small but significant effect size (Hedge's g = 0.29). There was no evidence of publication bias and heterogeneity of effect sizes across studies was moderate. Results suggest that sleep plays a protective role in the aftermath of exposure to a traumatic event with implications for early post-trauma intervention efforts.

The potential beneficial effect of sleep deprivation following traumatic events to preventing PTSD: Review of current insight regarding sleep, memory, and trauma resonating with ancient rituals-Àìsùn Oku (African) and Tsuya (Japanese)

Sleep figures in numerous ancient texts, for example, Epic of Gilgamesh, and has been a focus for countless mystical and philosophical texts. Even in the present century, sleep remains one of the most complex behaviors whose function still remains to be further explored. Current hypotheses suggest that among other functions, sleep contributes to memory processes. Memory is a core topic of study in post-traumatic stress disorder (PTSD) and other stress-related phenomena. It is widely accepted that sleep plays a major role in the consolidation of newly encoded hippocampus-dependent memories to pre-existing knowledge networks. Conversely, sleep deprivation disrupts consolidation and impairs memory retrieval. Along this line, sleep deprivation following a potentially traumatic event may interfere with the consolidation of event-related memories and, thereby, may reduce long-term post-traumatic stress-related symptoms. This review consolidates clinical and animal studies on the relationships between sleep, sleep deprivation, memory processes, and trauma exposure while introducing new contemporary insights into an ancient African tribal ritual (Àìsùn Oku) and Japanese ceremony ritual (Tsuya). We propose that these findings, focusing specifically on the effects of sleep deprivation in the immediate aftermath of traumatic events, may be explored as a possible therapeutic measure. Along with a summary of the field questions on whether sleep is performed "to remember" or "to forget" we lay the rationale for using sleep deprivation as a clinical tool. A tool that may partially prevent the long-term persistence of these traumatic events' memory and thereby, at least partly, attenuating the development of PTSD.

Modified prolonged exposure therapy as Early Intervention after Rape (The EIR-study): study protocol for a multicenter randomized add-on superiority trial

BACKGROUND

Sexual assault and rape are the traumatic life events with the highest probability for posttraumatic stress disorder (PTSD), which can have devastating consequences for those afflicted by the condition. Studies indicate that modified prolonged exposure (mPE) therapy may be effective in preventing the development of PTSD in recently traumatized individuals, and especially for people who have experienced sexual assault. If a brief, manualized early intervention can prevent or reduce post-traumatic symptoms in women who have recently experienced rape, healthcare services targeted for these populations (i.e., sexual assault centers, SACs) should consider implementing such interventions as part of routine care.

METHODS/DESIGN

This is a multicenter randomized controlled add-on superiority trial that enrolls patients attending sexual assault centers within 72 h after rape or attempted rape. The objective is to assess whether mPE shortly after rape can prevent the development of post-traumatic stress symptoms. Patients will be randomized to either mPE plus treatment as usual (TAU) or TAU alone. The primary outcome is the development of post-traumatic stress symptoms 3 months after trauma. Secondary outcomes will be symptoms of depression, sleep difficulties, pelvic floor hyperactivity, and sexual dysfunction. The first 22 subjects will constitute an internal pilot trial to test acceptance of the intervention and feasibility of the assessment battery.

DISCUSSION

This study will guide further research and clinical initiatives for implementing strategies for preventing post-traumatic stress symptoms after rape and provide new knowledge about which women may benefit the most from such initiatives and for revising existing treatment guidelines within this area.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05489133. Registered on 3 August 2022.

Investigating the effects of sleep and sleep loss on the different stages of episodic emotional memory: A narrative review and guide to the future

For two decades, sleep has been touted as one of the primary drivers for the encoding, consolidation, retention, and retrieval of episodic emotional memory. Recently, however, sleep's role in emotional memory processing has received renewed scrutiny as meta-analyses and reviews have indicated that sleep may only contribute a small effect that hinges on the content or context of the learning and retrieval episodes. On the one hand, the strong perception of sleep's importance in maintaining memory for emotional events may have been exacerbated by publication bias phenomena, such as the "winner's curse" and "file drawer problem." On the other hand, it is plausible that there are sets of circumstances that lead to consistent and reliable effects of sleep on emotional memory; these circumstances may depend on factors such as the placement and quality of sleep relative to the emotional experience, the content and context of the emotional experience, and the probes and strategies used to assess memory at retrieval. Here, we review the literature on how sleep (and sleep loss) influences each stage of emotional episodic memory. Specifically, we have separated previous work based on the placement of sleep and sleep loss in relation to the different stages of emotional memory processing: (1) prior to encoding, (2) immediately following encoding during early consolidation, (3) during extended consolidation, separated from initial learning, (4) just prior to retrieval, and (5) post-retrieval as memories may be restructured and reconsolidated. The goals of this review are three-fold: (1) examine phases of emotional memory that sleep may influence to a greater or lesser degree, (2) explicitly identify problematic overlaps in traditional sleep-wake study designs that are preventing the ability to better disentangle the potential role of sleep in the different stages of emotional memory processing, and (3) highlight areas for future research by identifying the stages of emotional memory processing in which the effect of sleep and sleep loss remains under-investigated. Here, we begin the task of better understanding the contexts and factors that influence the relationship between sleep and emotional memory processing and aim to be a valuable resource to facilitate hypothesis generation and promote important future research.

Sleep well, mind wander less: A systematic review of the relationship between sleep outcomes and spontaneous cognition

Despite an upsurge of research on spontaneous cognition, little is known about its associations with sleep-related outcomes. This systematic review, following PRISMA guidelines, examined the relationship between sleep and spontaneous thoughts, across different definitions and measurements of sleep outcomes and spontaneous cognition, and a diversity of methodologies. Twenty-one articles with survey and/or experimental designs were identified. Self-reported disturbed sleep-comprising poor sleep quality, more insomnia symptoms, more daytime sleepiness and a tendency towards eveningness-and experimentally induced sleep deprivation were associated with a tendency to engage in disruptive mind wandering and daydreaming, but not positive-constructive daydreaming. Findings regarding circadian fluctuation in spontaneous thoughts were mixed and inconclusive. This systematic review bridges the gap between the sleep and spontaneous cognition research by contributing to the understanding of potential psychological and cognitive mechanisms of spontaneous cognition, as well as by elucidating the emotional and cognitive consequences of disturbed sleep.

Roles for Sleep in Neural and Behavioral Plasticity: Reviewing Variation in the Consequences of Sleep Loss

Sleep is a vital physiological state that has been broadly conserved across the evolution of animal species. While the precise functions of sleep remain poorly understood, a large body of research has examined the negative consequences of sleep loss on neural and behavioral plasticity. While sleep disruption generally results in degraded neural plasticity and cognitive function, the impact of sleep loss can vary widely with age, between individuals, and across physiological contexts. Additionally, several recent studies indicate that sleep loss differentially impacts distinct neuronal populations within memory-encoding circuitry. These findings indicate that the negative consequences of sleep loss are not universally shared, and that identifying conditions that influence the resilience of an organism (or neuron type) to sleep loss might open future opportunities to examine sleep's core functions in the brain. Here, we discuss the functional roles for sleep in adaptive plasticity and review factors that can contribute to individual variations in sleep behavior and responses to sleep loss.

Anxiety levels and sleep quality in nursing students during the COVID-19 pandemic

PURPOSE

This study was carried out with the aim of determining the correlation between the levels of anxiety experienced by students and their sleep quality during the coronavirus disease 2019 (COVID-19) pandemic.

DESIGN AND METHODS

This descriptive and correlational type study' sample population was 283 students. The personal information form, state-trait anxiety inventory, Verran and Snyder-Halpern sleep scale were used in data collection.

FINDINGS

Study findings indicate that students' state-trait anxiety levels and sleep quality are average, 28.26% of them sleep interrupted and there is a correlation between their anxiety and sleep quality.

PRACTICE IMPLICATION

İt is recommended that teaching students how to deal with COVID-19 and interventional studies aimed at improving sleep quality by reducing anxiety levels should be conducted to further investigate the topic.

The Many Faces of Sleep Disorders in Post-Traumatic Stress Disorder: An Update on Clinical Features and Treatment

Sleep disorders and nightmares are core symptoms of post-traumatic stress disorder (PTSD). The relationship seems to be bidirectional, and persistent disturbed sleep may influence the course of the disorder. With regard to sleep quality, insomnia and nocturnal anxiety symptoms, as well as nightmares and stressful dreams, are the most prominent sleep symptoms. Polysomnographic measurements reveal alterations of the sleep architecture and fragmentation of rapid eye movement sleep. In addition, sleep disorders, such as sleep-related breathing disorders and parasomnias are frequent comorbid conditions. The complex etiology and symptomatology of trauma-related sleep disorders with frequent psychiatric comorbidity require the application of multimodal treatment concepts, including psychological and pharmacological interventions. However, there is little empirical evidence on the effectiveness of long-term drug treatment for insomnia and nightmares. For nondrug interventions, challenges arise from the current lack of PTSD-treatment concepts integrating sleep- and trauma-focused therapies. Effective therapy for sleep disturbances may consequently also improve well-being during the day and probably even the course of PTSD. Whether early sleep interventions exert a preventive effect on the development of PTSD remains to be clarified in future studies.

Sleep and Memory Consolidation Dysfunction in Psychiatric Disorders: Evidence for the Involvement of Extracellular Matrix Molecules

Sleep disturbances and memory dysfunction are key characteristics across psychiatric disorders. Recent advances have revealed insight into the role of sleep in memory consolidation, pointing to key overlap between memory consolidation processes and structural and molecular abnormalities in psychiatric disorders. Ongoing research regarding the molecular mechanisms involved in memory consolidation has the potential to identify therapeutic targets for memory dysfunction in psychiatric disorders and aging. Recent evidence from our group and others points to extracellular matrix molecules, including chondroitin sulfate proteoglycans and their endogenous proteases, as molecules that may underlie synaptic dysfunction in psychiatric disorders and memory consolidation during sleep. These molecules may provide a therapeutic targets for decreasing strength of reward memories in addiction and traumatic memories in PTSD, as well as restoring deficits in memory consolidation in schizophrenia and aging. We review the evidence for sleep and memory consolidation dysfunction in psychiatric disorders and aging in the context of current evidence pointing to the involvement of extracellular matrix molecules in these processes.

Effects of restraining measures due to COVID-19: Pre- and post-lockdown cognitive status and mental health

The COVID-19 pandemic has prompted all countries to adopt restraining measures to mitigate the spread of the disease. Usually, large-scale disasters tend to be accompanied by significant increases of psychological distress, depression and anxiety. Confinement measures imposed during the COVID-19 pandemic are likely to have similar consequences. In the present study we aim to evaluate how COVID-19 affected the overall psychological functioning of Portuguese individuals by providing a comparison of current data with status prior to the COVID-19 pandemic. The study sample was composed of 150 cognitively healthy participants. Results show an overall maintenance of cognitive capacities, although subjective cognitive decline complaints significantly increased during the pandemic. Regarding mental health, restraining measures culminated in an aggravation of depressive and decrease of the perceived quality of life, associated with feelings of loneliness and perceived social isolation. Finally, higher levels of pre-COVID-19 quality of life seem to play a protective role against depression and anxiety and predict less difficulties in emotion regulation, feelings of solitude and cognitive complaints. In sum, confinement due to COVID-19 implied an aggravation of the mental health of the Portuguese population, which appears to have been attenuated in those with higher pre-pandemic levels of perceived quality of life.

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.

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.

A Polish and German Population Study of Quality of Life, Well-Being, and Life Satisfaction in Older Adults During the COVID-19 Pandemic

Introduction: Psychological studies undertaken during the COVID-19 pandemic rarely include people in their 60s or older. In our study, we studied the predictors of quality of life, well-being, and life satisfaction (including risky behavior, trait anxiety, feeling of threat, sleep quality, and optimism) during the pandemic in older people from Germany and Poland and compared them to three different age groups. Methods: A total of 494 adults in four groups-60+ (N = 60), 50-60 (N = 139), 36-49 (N = 155), <35 (N = 140)-completed validated self-report questionnaires assessing: socio-demographic data, quality of life, trait anxiety, risk tolerance, Coronavirus threat, optimism regarding the pandemic, difficulty relaxing, life satisfaction, well-being, and sleep quality during the pandemic period. Results: Older people rated their quality of life higher than did young (mean difference=0.74, SE=0.19, p < 0.01) and middle-aged (mean difference=0.79, SE=0.18, p < 0.01) participants, rated their life satisfaction higher than young (mean difference=1.23, SE = 0.31, p < 0.01) and middle-aged (mean difference=0.92, SE = 0.30, p < 0.05) participants, and rated their well-being higher than young (mean difference=1.40, SE = 0.31, p < 0.01) and middle-aged (mean difference=0.91, SE = 0.31, p < 0.05) participants. They also experienced lower levels of trait anxiety and Coronavirus threat (mean difference=-9.19, SE = 1.90, p < 0.01) than the younger age groups. They experienced greater risk tolerance (mean difference=1.38, SE=0.33, p < 0.01), sleep quality (F =1 .25; eta 2 = 0.01), and optimism (F = 1.96; eta 2 = 0.01), and had less difficulty relaxing during the pandemic (F = 3.75; eta 2 = 0.02) than middle-aged respondents. Conclusions: Quality of life, life satisfaction, and well-being during the pandemic is affected by age, trait anxiety, and Coronavirus threat. Older people rated their quality of life, life satisfaction, and well-being during pandemic higher than young people, and experienced lower levels of trait anxiety and Coronavirus threat than the younger age groups. They experienced greater risk tolerance, sleep quality, and optimism, and had less difficulty relaxing than middle-aged respondents.

The enemy who sealed the world: effects quarantine due to the COVID-19 on sleep quality, anxiety, and psychological distress in the Italian population

Background

The 2019 Coronavirus Disease (COVID-19) pandemic has become a global health emergency. The extreme actions aimed to reduce virus diffusion have profoundly changed the lifestyles of the Italian population. Moreover, fear of contracting the infection has generated high levels of anxiety. This study aimed to understand the psychological impact of the COVID-19 outbreak on sleep quality, general anxiety symptomatology, and psychological distress.

Methods

An online survey collected information on socio-demographic data and additional information concerning the COVID-19 pandemic. Furthermore, sleep quality, sleep disorders, generalized anxiety symptoms, psychological distress, and post-traumatic stress disorder (PTSD) symptomatology related to COVID-19 were assessed.

Results

This study included 2291 respondents. The results revealed that 57.1% of participants reported poor sleep quality, 32.1% high anxiety, 41.8% high distress, and 7.6% reported PTSD symptomatology linked to COVID-19. Youth and women, those uncertain regarding possible COVID-19 infection, and greater fear of direct contact with those infected by COVID-19 had an increased risk of developing sleep disturbances, as well as higher levels of anxiety and distress. Finally, a significant relationship between sleep quality, generalized anxiety, and psychological distress with PTSD symptoms related to COVID-19 was evidenced.

Conclusions

Our findings indicate that the COVID-19 pandemic appears to be a risk factor for sleep disorders and psychological diseases in the Italian population, as previously reported in China. These results should be used as a starting point for further studies aimed to develop psychological interventions to minimize the brief and long-term consequences of the COVID-19 pandemic.

Hyper-Activation of mPFC Underlies Specific Traumatic Stress-Induced Sleep-Wake EEG Disturbances

Sleep disturbances have been recognized as a core symptom of post-traumatic stress disorders (PTSD). However, the neural basis of PTSD-related sleep disturbances remains unclear. It has been challenging to establish the causality link between a specific brain region and traumatic stress-induced sleep abnormalities. Here, we found that single prolonged stress (SPS) could induce acute changes in sleep/wake duration as well as short- and long-term electroencephalogram (EEG) alterations in the isogenic mouse model. Moreover, the medial prefrontal cortex (mPFC) showed persistent high number of c-fos expressing neurons, of which more than 95% are excitatory neurons, during and immediately after SPS. Chemogenetic inhibition of the prelimbic region of mPFC during SPS could specifically reverse the SPS-induced acute suppression of delta power (1–4 Hz EEG) of non-rapid-eye-movement sleep (NREMS) as well as most of long-term EEG abnormalities. These findings suggest a causality link between hyper-activation of mPFC neurons and traumatic stress-induced specific sleep–wake EEG disturbances.

Sleep and intrusive memories immediately after a traumatic event in emergency department patients

STUDY OBJECTIVES

Intrusive memories of psychological trauma are a core clinical feature of posttraumatic stress disorder (PTSD), and in the early period post-trauma may be a potential target for early intervention. Disrupted sleep in the weeks post-trauma is associated with later PTSD. The impact of sleep and intrusive memories immediately post-trauma, and their relation to later PTSD, is unknown. This study assessed the relationship between sleep duration on the first night following a real-life traumatic event and intrusive memories in the subsequent week, and how these might relate to PTSD symptoms at 2 months.

METHODS

Patients (n = 87) recruited in the emergency department completed a sleep and intrusive memory diary from the day of their trauma and for the subsequent week, with optional actigraphy. PTSD, anxiety, and depression symptoms were assessed at 1 week and 2 months.

RESULTS

A U-shaped relationship was observed between sleep duration on the first night and intrusive memories over the subsequent week: sleeping "too little" or "too much" was associated with more intrusive memories. Individuals who met Clinician-Administered PTSD Scale (CAPS) criteria for PTSD at 2 months had three times more intrusive memories in the first week immediately post-trauma than those who did not (M = 28.20 vs 9.96). Post hoc analysis showed that the absence of intrusive memories in the first week post-trauma was only observed in those who did not meet CAPS criteria for PTSD at 2 months.

CONCLUSIONS

Monitoring intrusive memories and sleep in the first week post-trauma, using a simple diary, may help identify individuals more vulnerable to later psychopathology.

Circadian Rhythms of Perineuronal Net Composition

Perineuronal nets (PNNs) are extracellular matrix (ECM) structures that envelop neurons and regulate synaptic functions. Long thought to be stable structures, PNNs have been recently shown to respond dynamically during learning, potentially regulating the formation of new synapses. We postulated that PNNs vary during sleep, a period of active synaptic modification. Notably, PNN components are cleaved by matrix proteases such as the protease cathepsin-S. This protease is diurnally expressed in the mouse cortex, coinciding with dendritic spine density rhythms. Thus, cathepsin-S may contribute to PNN remodeling during sleep, mediating synaptic reorganization. These studies were designed to test the hypothesis that PNN numbers vary in a diurnal manner in the rodent and human brain, as well as in a circadian manner in the rodent brain, and that these rhythms are disrupted by sleep deprivation. In mice, we observed diurnal and circadian rhythms of PNNs labeled with the lectin Wisteria floribunda agglutinin (WFA+ PNNs) in several brain regions involved in emotional memory processing. Sleep deprivation prevented the daytime decrease of WFA+ PNNs and enhances fear memory extinction. Diurnal rhythms of cathepsin-S expression in microglia were observed in the same brain regions, opposite to PNN rhythms. Finally, incubation of mouse sections with cathepsin-S eliminated PNN labeling. In humans, WFA+ PNNs showed a diurnal rhythm in the amygdala and thalamic reticular nucleus (TRN). Our results demonstrate that PNNs vary in a circadian manner and this is disrupted by sleep deprivation. We suggest that rhythmic modification of PNNs may contribute to memory consolidation during sleep.

Interrupting traumatic memories in the emergency department: a randomized controlled pilot study

BACKGROUND

The hours immediately following a traumatic event may present a window of opportunity to interrupt the consolidation of memories of the traumatic event, and this may prevent PTSD development. This theory has been validated in a series of analogue studies, showing that a visuo-spatial task reduces intrusive memories, however clinical studies are scarce.

OBJECTIVE

This pilot RCT examined the use of a semi-immersive Virtual Reality visuospatial task, as an intervention to interrupt memory consolidation, in the Emergency Department (ED) in the immediate hours following a traumatic event. We hypothesised that participants who had received the intervention would present with lower levels of PTSD symptoms than the control group who received no intervention.

METHOD

Seventy-seven adult survivors of traumatic events, meeting study criteria, were recruited in the ED of a Level III Trauma Centre. Survivors arrived at the ED less than one hour, on average, after the trauma. After signing informed consent, participants were randomized to the SnowWorld intervention or control group. Both groups completed self-report questionnaires, and the intervention group used SnowWorld for up to 10 minutes.

RESULTS

No significant differences between the intervention and control groups were found regarding PTSD symptom levels two weeks and six months following the traumatic event.

CONCLUSIONS

These results add to the growing literature examining the use of a concurrent task to reduce intrusions following a traumatic event. In contrast to previous clinical studies, this study did not show significant group differences; however, it replicates an analogue study that used a specifically developed app. Further studies are needed to elucidate possible reasons for these conflicting results.

Rodent models of post-traumatic stress disorder: behavioral assessment

Although the etiology and expression of psychiatric disorders are complex, mammals show biologically preserved behavioral and neurobiological responses to valent stimuli which underlie the use of rodent models of post-traumatic stress disorder (PTSD). PTSD is a complex phenotype that is difficult to model in rodents because it is diagnosed by patient interview and influenced by both environmental and genetic factors. However, given that PTSD results from traumatic experiences, rodent models can simulate stress induction and disorder development. By manipulating stress type, intensity, duration, and frequency, preclinical models reflect core PTSD phenotypes, measured through various behavioral assays. Paradigms precipitate the disorder by applying physical, social, and psychological stressors individually or in combination. This review discusses the methods used to trigger and evaluate PTSD-like phenotypes. It highlights studies employing each stress model and evaluates their translational efficacies against DSM-5, validity criteria, and criteria proposed by Yehuda and Antelman's commentary in 1993. This is intended to aid in paradigm selection by informing readers about rodent models, their benefits to the clinical community, challenges associated with the translational models, and opportunities for future work. To inform PTSD model validity and relevance to human psychopathology, we propose that models incorporate behavioral test batteries, individual differences, sex differences, strain and stock differences, early life stress effects, biomarkers, stringent success criteria for drug development, Research Domain Criteria, technological advances, and cross-species comparisons. We conclude that, despite the challenges, animal studies will be pivotal to advances in understanding PTSD and the neurobiology of stress.

Investigation of the impact of total sleep deprivation at home on the number of intrusive memories to an analogue trauma

Sleep enhances the consolidation of memory; however, this property of sleep may be detrimental in situations where memories of an event can lead to psychopathology, such as following a traumatic event. Intrusive memories of trauma are emotional memories that spring to mind involuntarily and are a core feature of post-traumatic stress disorder. Total sleep deprivation in a hospital setting on the first night after an analogue trauma (a trauma film) led to fewer intrusive memories compared to sleep as usual in one study. The current study aimed to test an extension of these findings: sleep deprivation under more naturalistic conditions-at home. Polysomnographic recordings show inconsistent sleep deprivation was achieved at home. Fewer intrusive memories were reported on day 1 after the trauma film in the sleep-deprived condition. On day 2 the opposite was found: more intrusive memories in the sleep-deprived condition. However, no significant differences were found with the removal of two participants with extreme values and no difference was found in the total number of intrusive memories reported in the week following the trauma film. Voluntary memory of the trauma film was found to be slightly impaired in the sleep deprivation condition. In conclusion, compared to our eariler findings using total sleep deprivation in a hospital setting, in the current study the use of inconsistent sleep deprivation at home does not replicate the pattern of results on reducing the number of intrusive memories. Considering the conditions under which sleep deprivation (naturalistic versus hospital) was achieved requires further examination.

Multilevel Interactions of Stress and Circadian System: Implications for Traumatic Stress

The dramatic fluctuations in energy demands by the rhythmic succession of night and day on our planet has prompted a geophysical evolutionary need for biological temporal organization across phylogeny. The intrinsic circadian timing system (CS) represents a highly conserved and sophisticated internal "clock," adjusted to the 24-h rotation period of the earth, enabling a nyctohemeral coordination of numerous physiologic processes, from gene expression to behavior. The human CS is tightly and bidirectionally interconnected to the stress system (SS). Both systems are fundamental for survival and regulate each other's activity in order to prepare the organism for the anticipated cyclic challenges. Thereby, the understanding of the temporal relationship between stressors and stress responses is critical for the comprehension of the molecular basis of physiology and pathogenesis of disease. A critical loss of the harmonious timed order at different organizational levels may affect the fundamental properties of neuroendocrine, immune, and autonomic systems, leading to a breakdown of biobehavioral adaptative mechanisms with increased stress sensitivity and vulnerability. In this review, following an overview of the functional components of the SS and CS, we present their multilevel interactions and discuss how traumatic stress can alter the interplay between the two systems. Circadian dysregulation after traumatic stress exposure may represent a core feature of trauma-related disorders mediating enduring neurobiological correlates of trauma through maladaptive stress regulation. Understanding the mechanisms susceptible to circadian dysregulation and their role in stress-related disorders could provide new insights into disease mechanisms, advancing psychochronobiological treatment possibilities and preventive strategies in stress-exposed populations.

Sleep in the Intensive Care Unit in a Model of Family-Centered Care

The desire for families to be physically present to support their loved ones in the intensive care unit, and guidelines in favor of this open visitation approach, require that clinicians consider both patient and family sleep. This article reviews the causes of poor sleep for patients and their family members in the intensive care unit as well as the expected changes in cognition and emotion that can result from sleep deprivation. Measures are proposed to improve the intensive care unit environment to promote family sleep. A framework to educate family members and engage them in preservation of their and their loved one's circadian rhythm is also presented. Although further research is needed, the proposed framework has the potential to improve outcomes for patients and their families in the intensive care unit.

Sleep and Dreaming in Posttraumatic Stress Disorder

PURPOSE OF REVIEW

Sleep disturbances are core features of posttraumatic stress disorder (PTSD). This review aims to characterize sleep disturbances, summarize the knowledge regarding the relationships between trauma exposure and sleep difficulties, and highlight empirically supported and/or utilized treatments for trauma-related nightmares and insomnia.

RECENT FINDINGS

Trauma-related nightmares and insomnia, and other sleep disorders, are frequently reported among trauma survivors. The roles of fear of sleep, REM density, and decreased parasympathetic activity are beginning to inform the relationship between trauma exposure and sleep difficulties. Additionally, the potential adaptive role of sleep loss immediately following a traumatic experience is being recognized. Interventions targeting these sleep disturbances show promise in reducing symptoms. Research in understanding the role of sleep on the development, course, and treatment of PTSD is expanding. Longitudinal investigations are needed to further elucidate these relationships and identify treatments most effective in ameliorating symptoms.