Understanding nightmares after traumatic events in Detroit (UNiTED): prospective associations with interpersonal violence and posttraumatic stress disorder symptoms

ABSTRACTBackground: Research suggests trauma-related nightmares (TRNs) during the acute aftermath of trauma may contribute to posttraumatic stress disorder (PTSD). However, it is unknown who is most vulnerable to TRNs, which is critical to identify at-risk patients toward whom early nightmare-focused treatments can be targeted to prevent PTSD.Objective: We tested trauma type (interpersonal violence [e.g. assault] vs non-interpersonal trauma [e.g. motor vehicle collision]) as a risk factor for TRNs in a predominantly low-income, Black, urban sample in Detroit, MI, USA.Method: We recruited patients from the intensive care unit following traumatic injury (N = 88; Mage = 39.53 ± SD 14.31 years, 67.0% male, 67.0% Black, 47.7% annual income ≤ $20,000) and administered surveys at three post trauma timepoints: one week (T1), one month (T2; n = 61), and two months (T3; n = 59). Trauma type was assessed at T1 via electronic medical records. Participants reported the extent to which their dreams' content was similar to the trauma for which they were hospitalized across T1-T3. Participants then completed the PTSD Checklist for DSM-5 at T3.Results: TRNs were more prevalent over time among patients exposed to interpersonal violence (80%) vs non-interpersonal trauma (48.7%, p = .005). Patients hospitalized for interpersonal violence faced greater odds for TRNs across timepoints relative to non-interpersonal trauma patients (Odds Ratio = 4.95, p = .021). TRNs, in turn, prospectively predicted PTSD symptoms such that TRNs at T2 presaged more severe PTSD at T3 (p = .040, ηp2 = .31), above and beyond T1 PTSD status.Conclusions: This prospective study provides first evidence that interpersonal violence exposure is a robust risk factor for TRNs, which prospectively contribute to PTSD symptom development. Early intervention on TRNs after interpersonal violence exposure may decrease PTSD risk. Future studies are encouraged to use ambulatory methods to capture nightmares sooner after they occur.

How emotions impact sleep: A quantitative review of experiments

Although sleep and emotional processes are recognized as mutually dependent, the causal impact of emotions on sleep has been comparatively neglected. To appraise evidence for the causal influence of emotions on sleep, a meta-analysis of the existing experimental literature evaluated the strength, form, and context of experimental effects of emotion inductions on sleep parameters (k = 31). Quality of experiments was evaluated, and theoretically-relevant features were extracted and examined as moderating factors of observed effects (i.e., sleep parameter, design, sleep context, types of emotion inductions and emotions). Random-effect models were used to aggregate effects for each sleep parameter, while-mixed effect models examined moderators. There was a significant impact of emotion inductions on delayed sleep onset latency (D = 3.36 min, 95%CI [1.78, 4.94], g = 0.53), but not other parameters. There was little evidence of publication bias regarding sleep-onset latency effect, the studies overall were heterogeneous, sometimes of limited methodological quality, and could only detect moderate-to-large impacts. The findings supported the hypothesis that negative emotions delayed sleep onset, but evidence regarding other sleep parameters was inconclusive. The results call for more targeted investigation to disambiguate distinct features of emotions and their import for sleep.

To sleep or not to sleep, that is the question: A systematic review and meta-analysis on the effect of post-trauma sleep on intrusive memories of analog trauma

Distressing intrusive memories of a traumatic event are one of the hallmark symptoms of posttraumatic stress disorder. Thus, it is crucial to identify early interventions that prevent the occurrence of intrusive memories. Both, sleep and sleep deprivation have been discussed as such interventions, yet previous studies yielded contradicting effects. Our systematic review aims at evaluating existing evidence by means of traditional and individual participant data (IPD) meta-analyses to overcome power issues of sleep research. Until May 16th, 2022, six databases were searched for experimental analog studies examining the effect of post-trauma sleep versus wakefulness on intrusive memories. Nine studies were included in our traditional meta-analysis (8 in the IPD meta-analysis). Our analysis provided evidence for a small effect favoring sleep over wakefulness, log-ROM = 0.25, p < .001, suggesting that sleep is associated with a lower number of intrusions but unrelated to the occurrence of any versus no intrusions. We found no evidence for an effect of sleep on intrusion distress. Heterogeneity was low and certainty of evidence for our primary analysis was moderate. Our findings suggest that post-trauma sleep has the potential to be protective by reducing intrusion frequency. More research is needed to determine the impact following real-world trauma and the potential clinical significance.

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.

Sleep and day-to-day PTSD symptom variability: an ecological momentary assessment and actigraphy monitored study in trauma-exposed young adults

BACKGROUND

Disrupted sleep and post-traumatic stress disorder (PTSD) are bi-directionally linked and have been found to mutually reinforce each other on a day-to-day basis. However, most of the previous research has focused on subjective measures of sleep only.

OBJECTIVE

Here, we investigated the temporal relationship between sleep and PTSD symptoms using both subjective (sleep diary) and objective measures of sleep (actigraphy).

METHODS

Forty-one non-treatment seeking, trauma exposed young adults (age M = 24.68, SD = 8.15) with a range of PTSD symptom severities (PTSS, 0-53 on PCL-5) were recruited. Participants completed two surveys per day over four weeks to measure day-time PTSD symptoms (i.e. PTSS and number of intrusions) and night-time sleep subjectively, while wearing an actigraphy watch to measure sleep objectively.

RESULTS

Linear mixed models revealed that subjectively reported sleep disruptions were associated with elevated next-day PTSS and increasing number of intrusive memories both within and between participants. Similar results were found for daytime PTSD symptoms on night-time sleep. However, these associations were not found using objective sleep data. Exploratory moderator analyses including sex (male vs. female) found that these associations differed in strength between sexes but were generally in the same direction.

DISCUSSION

These results were in line with our hypothesis with regards to the sleep diary (subjective sleep), but not actigraphy (objective sleep). Several factors which have implications on both PTSD and sleep, such as the COVID-19 pandemic and/ or sleep-state misperception, may be potential reasons behind those discrepancies. However, this study had limited power and needs to be replicated in larger samples. Nonetheless, these results add to the current literature about the bi-directional relationship between sleep and PTSD and have clinical implications for treatment strategies.

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.

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.

Sleep's role in updating aversive autobiographical memories

Aversive autobiographical memories play a key role in the development and maintenance of many mental disorders. Imagery rescripting is a well-established psychotherapeutic intervention aiming to create a more adaptive version of an aversive memory by modifying its interpretation. Sleep has been shown to support reconsolidation of updated neutral memories. Here, we investigated in healthy participants whether a 90-min nap compared to wake supports the adaptive reconsolidation of autobiographical memories. Forty-four university students received a single 50-min imagery rescripting session. Thereafter, half of the participants took a 90-min nap, whereas the other half stayed awake. Subjective (arousal ratings, reports of emotions and dysfunctional cognitions) and heart rate (HR) responses to individual memory scripts were measured before the intervention (pre), after the 90-min retention interval (post 1) and 7 days later (post 2). Results demonstrate a significant decrease in distress of aversive memories pre to post imagery rescripting. The nap group showed less distressing dysfunctional cognitions along with a lower HR in response to the negative memory script as compared to the wake group at post 1. These differences were no longer evident 1 week later (post 2). Central sleep spindle density during the nap was correlated with the reduction in HR in response to the negative memory script from pre to post 1. Our results provide first evidence for sleep benefitting adaptive reconsolidation of aversive autobiographical memories. Future research should expand this approach to clinical populations and investigate precise conditions under which sleep may benefit psychotherapeutic interventions utilizing reconsolidation mechanisms.

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.

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.