睡眠对恐惧学习的影响及其认知神经机制

睡眠问题可能会诱发恐惧相关情绪障碍(焦虑、创伤性应激障碍、恐怖症等),研究睡眠影响恐惧学习的认知神经机制,有助于增强对恐惧相关情绪障碍的预测、诊断和治疗。以往研究表明睡眠剥夺影响恐惧习得和消退主要是通过抑制vmPFC活动,阻碍其与杏仁核的功能连接,从而导致恐惧习得增强或是消退学习受损。进一步研究发现睡眠不同阶段对恐惧学习相关脑区有独特的影响:剥夺(缺乏)快速眼动睡眠会抑制vmPFC活动、增强杏仁核、海马激活,导致恐惧习得增强,消退学习受损,此外边缘皮层的功能连接减少破坏了记忆巩固(恐惧记忆和消退记忆);而慢波睡眠主要与海马变化有关,慢波睡眠期间进行目标记忆重激活可促进恐惧消退学习。未来研究需要增加睡眠影响恐惧泛化的神经机制研究、及昼夜节律中断对恐惧消退的影响,以及关注动物睡眠研究向人类睡眠研究转化中存在的问题。     

Subjective Sleep Disturbances in Sexual Assault Survivors: Associations With Trauma and Posttraumatic Stress Disorder Symptom Severity

Prior work implicates sleep disturbance in the development and maintenance of posttraumatic stress disorder (PTSD). However, the majority of this literature has focused on combat veteran men, and limited work has examined links between sleep disturbance and PTSD symptoms in sexual assault survivors. This is a notable gap in the literature, as sexual trauma is disproportionately likely to result in PTSD and is more common in women. We sought to examine the relations between subjective sleep disturbance, sexual assault severity, and PTSD symptoms in a sample of sexual assault survivors with PTSD (PTSD+), without PTSD (PTSD-), and healthy controls. The sample (N = 60) completed the Insomnia Severity Index and prospectively monitored their sleep for 1 week using the Consensus Sleep Diary. The sexual assault survivors also completed the Sexual Experiences Survey and PTSD Checklist-5. Results of group comparisons found that the PTSD+ group reported significantly higher insomnia symptoms, longer sleep onset latency, more nocturnal awakenings, and lower sleep quality compared to the healthy control group and higher insomnia symptoms compared to the PTSD- group. Results of regression analyses in the sexual assault survivors found that insomnia symptoms and number of nocturnal awakenings were significantly associated with higher PTSD symptoms, and sexual assault severity was significantly associated with higher insomnia symptoms, longer sleep onset latency, and lower sleep quality. These findings highlight specific features of sleep disturbance that are linked to trauma and PTSD symptom severity among sexual assault survivors.     

REM Sleep Bout Duration and Frequency in PTSD

The few pharmacological treatments shown to be effective in reducing sleep disturbance in posttraumatic stress disorder (PTSD) might work through normalization of rapid eye movement (REM). However, evidence of REM sleep disturbance in PTSD has been inconsistent and the definition of REM bout has varied as well. In this study, we compared polysomnographic findings in adults with PTSD to both normal sleepers and insomniacs. We found no differences between those with and without PTSD on REM bout frequency or duration. We did, however, find gender differences within our PTSD sample as consistent with a previous review suggesting that males with PTSD are more likely to demonstrate REM sleep disturbance. Consensus on REM bout definition is needed, in addition to studies powered to detect gender differences.     

The Relationship Between Postdeployment Factors and PTSD Severity in Recent Combat Veterans

Combat traumas precipitate posttraumatic stress disorder (PTSD); however, nontraumatic deployment and postdeployment factors may also contribute to PTSD severity. The Deployment Risk and Resilience Inventory (DRRI) was used to investigate pre-, peri-, and postdeployment factors associated with current PTSD severity in 150 recent combat veterans with PTSD and hazardous alcohol use. Hierarchal linear regression analyzed what factors independently predicted PTSD severity when controlling for sociodemographic characteristics and combat specific variables. Four postdeployment factors independently predicted PTSD severity: unemployment, alcohol use, social support, and stressful (nontraumatic) life events. The centrality of trauma in the maintenance of PTSD and clinical implications for treatment providers are discussed.     

Altered sleep in Borderline Personality Disorder in relation to the core dimensions of psychopathology

The aim of the study was to review the literature regarding sleep disturbances in Borderline Personality Disorder (BPD) and to relate the reported sleep alterations to the underlying core dimensions of BPD pathology. We present a qualitative and theoretical review regarding the empirical studies that investigated objective and subjective sleep quality in BPD and in different psychiatric conditions showing high co‐morbidity with this disorder. We show that disturbed sleep including sleep fragmentation, alterations in Slow Wave Sleep and REM sleep, and dysphoric dreaming are prevalent symptoms in BPD. We provide a framework relating the specific sleep alterations to the core dimensions of BPD pathology in order to clarify the inconsistencies of the different findings. The specific sleep disturbances in BPD seem to be related to different dimensions of psychopathological functioning and may have detrimental consequences on waking affect and cognition. Investigating disturbed sleep in BPD in relation to waking symptoms and underlying neural functioning would shed more light on the nature of this complex disorder. Moreover, a stronger emphasis on sleep disturbances would enrich the treatment protocols of BPD.     

Physiological arousal and attention in veterans with posttraumatic stress disorder

Psychophysiological reactivity has been well documented in WWII, Korean Conflict, and Vietnam veterans with posttraumatic stress disorder (PTSD). In addition, these individuals have demonstrated cognitive impairments within the domains of attention, concentration, new learning, and memory. However, there has been no research examining the impact of physiological arousal on attention in individuals with PTSD. This study documents the level of physiological arousal and associated disruption of attentional abilities in 28 Persian Gulf War veterans (18 without PTSD or other psychopathology and 10 with PTSD). This population represents a group of combat trauma victims who experienced a relatively acute onset of PTSD, thus providing a unique opportunity to compare prior psychophysiological and cognitive results with a group of veterans who manifested a recent onset of PTSD. Results indicated relatively comparable psychophysiological reactivity and arousal between Persian Gulf War veterans with PTSD and Persian Gulf War veterans without PTSD. Furthermore, attentional processes of veterans with PTSD were not more disrupted than in comparison soldiers. Results suggest that the intensity and chronicity of the disorder may impact physiological arousal and disruption of cognitive functioning. Following Persian Gulf War veterans with PTSD over time may reveal that psychophysiological arousal becomes more pronounced with chronicity, perhaps as memory networks become strengthened and/or neuroendocrine systems become increasingly disrupted.     

Effects of a brief behavioral treatment for PTSD-related sleep disturbances: a pilot study

OBJECTIVE: Sleep disturbances are a core feature of post-traumatic stress disorder (PTSD), and are often resistant to first-line pharmacological and psychological PTSD interventions. The goal of this pilot study was to explore the effects of a very brief intervention for PTSD-related nightmares and insomnia in victims of violent crimes with PTSD. METHODS: Seven adult victims of violent crimes with a current diagnosis of PTSD received a single, 90-min intervention session that used cognitive-behavioral techniques aimed at reducing post-traumatic nightmares and insomnia. Sleep diary measures, and measures of sleep quality, PTSD severity, anxiety, and depression were completed at baseline and 6 weeks post-intervention. RESULTS: Improvements in self-report and sleep diary measures of sleep quality and dream frequency were observed post-intervention. Clinically meaningful reductions in daytime PTSD symptom severity were also observed. CONCLUSIONS: A very brief behavioral intervention targeting post-traumatic nightmares and insomnia was associated with significant improvements in sleep and daytime PTSD symptom severity. Brief sleep-focused intervention may be helpful adjuncts to first-line PTSD treatments.     

Sleep and Sleep Disorders in Older Adults

A common but significant change associated with aging is a profound disruption to the daily sleep-wake cycle. It has been estimated that as many as 50% of older adults complain about difficulty initiating or maintaining sleep. Poor sleep results in increased risk of significant morbidity and mortality. Moreover, in younger adults, compromised sleep has been shown to have a consistent effect on cognitive function, which may suggest that sleep problems contribute to the cognitive changes that accompany older age. The multifactorial nature of variables affecting sleep in old age cannot be overstated. Changes in sleep have been thought to reflect normal developmental processes, which can be further compromised by sleep disturbances secondary to medical or psychiatric diseases (e.g., chronic pain, dementia, depression), a primary sleep disorder that can itself be age-related (e.g., Sleep Disordered Breathing and Periodic Limb Movements During Sleep), or some combination of any of these factors. Given that changes in sleep quality and quantity in later life have implications for quality of life and level of functioning, it is imperative to distinguish the normal age-related sleep changes from those originating from pathological processes.     

Anxiety buffer disruption theory: a terror management account of posttraumatic stress disorder

We present anxiety buffer disruption theory (ABDT) and provide a review of current evidence regarding the theory. ABDT is an application of terror management theory to explain diverse reactions to traumatic events and the onset and maintenance of posttraumatic stress disorder (PTSD). It posits that PTSD results from a disruption in one's anxiety-buffering mechanisms, which normally provide protection against anxiety in general and death anxiety in particular. The disruption of these mechanisms leaves the individual defenseless in the face of overwhelming anxiety, which leads to the major symptom clusters of PTSD: re-experiencing, hyper-arousal, and avoidance. According to ABDT, because of the disruption in their anxiety-buffering mechanisms, individuals with PTSD symptoms do not respond to mortality reminders in the defensive ways that psychologically healthier individuals do. We review four sets of studies conducted in four different cultures and with people who have experienced different types of trauma, which reveal this atypical response pattern and lend support to ABDT.     

Trauma reactivity, avoidant coping, and PTSD symptoms: a moderating relationship?

In the immediate aftermath of a traumatic event, many individuals experience physiological reactivity in response to reminders of the traumatic event that typically lessens over time. However, an overreliance on avoidant coping strategies may interfere with the natural recovery process, particularly for those who are highly reactive to trauma reminders. In the current investigation, we examined avoidant coping as a moderator of the association between heart rate reactivity to a trauma monologue measured shortly after a traumatic event and severity of posttraumatic stress disorder (PTSD) symptoms measured several months later. Fifty-five female survivors of assault completed PTSD diagnostic interviews and a self-report coping measure and participated in a trauma monologue procedure that included continuous heart rate measurement. These procedures were completed within 1 month of the assault and again 3 months postassault. After we controlled for the effect of initial symptom levels, the interaction of heart rate reactivity to the trauma monologue and avoidant coping measured at Time 1 was associated with PTSD symptom severity at Time 2. Individuals who are relatively highly reliant on avoidant coping strategies and relatively highly reactive to trauma reminders may be at greatest risk of maintaining or potentially increasing their PTSD symptoms within the first few months following the trauma. These findings may help inform early intervention efforts for survivors of traumatic events.     

Interpersonal hostility and violence in vietnam combat veterans with chronic posttraumatic stress disorder: A review of theoretical models and empirical evidence

There is strong evidence that anger and violence are prevalent problems in Vietnam combat veterans with posttraumatic stress disorder, and a summary of relevant empirical studies is presented. However, the pathways responsible for development and perpetuation of anger and violence in this clinical population have been unidentified. Available information processing and neurobiological models regarding how anger and aggression may be dysregulated in response to trauma are reviewed. Anger and interpersonal violence in Vietnam veterans with PTSD may have a distinct etiology and maintenance compared to other disorders, and may be directly related to neurobiological and trauma-related factors. Although anger has not yet been directly modeled in accordance with theories of PTSD, these models may provide frameworks for investigating how anger may be associated with the development and maintenance of PTSD. Additional suggestions for future research are offered.     

Unwanted memories of assault: what intrusion characteristics are associated with PTSD?

Intrusive memories are common in the immediate aftermath of traumatic events, but neither their presence or frequency are good predictors of the persistence of posttraumatic stress disorder (PTSD). Two studies of assault survivors, a cross-sectional study (N=81) and a 6-month prospective longitudinal study (N=73), explored whether characteristics of the intrusive memories improve the prediction. Intrusion characteristics were assessed with an Intrusion Interview and an Intrusion Provocation Task. The distress caused by the intrusions, their "here and now" quality, and their lack of a context predicted PTSD severity. The presence of intrusive memories only explained 9% of the variance of PTSD severity at 6 months after assault. Among survivors with intrusions, intrusion frequency only explained 8% of the variance of PTSD symptom severity at 6 months. Nowness, distress and lack of context explained an additional 43% of the variance. These intrusion characteristics also predicted PTSD severity at 6 months over and above what could be predicted from PTSD diagnostic status at initial assessment. Further predictors of PTSD severity were rumination about the intrusive memories, and the ease and persistence with which intrusive memories could be triggered by photographs depicting assaults. The results have implications for the early identification of trauma survivors at risk of chronic PTSD.     

Inducing and modulating intrusive emotional memories: a review of the trauma film paradigm

Highly affect-laden memory intrusions are a feature of several psychological disorders with intrusive images of trauma especially associated with post-traumatic stress disorder (PTSD). The trauma film paradigm provides a prospective experimental tool for investigating analogue peri-traumatic cognitive mechanisms underlying intrusion development. We review several historical papers and some more recent key studies that have used the trauma film paradigm. A heuristic diagram is presented, designed to simplify predictions about analogue peri-traumatic processing and intrusion development, which can also be related to the processing elements of recent cognitive models of PTSD. Results show intrusions can be induced in the laboratory and their frequency amplified/attenuated in line with predictions. Successful manipulations include competing task type (visuospatial vs. verbal) and use of a cognitive coping strategy. Studies show that spontaneous peri-traumatic dissociation also affects intrusion frequency although attempts to manipulate dissociation have failed. It is hoped that further use of this paradigm may lead to prophylactic training for at risk groups and an improved understanding of intrusions across psychopathologies.     

Sleep Symptoms as a Partial Mediator Between Combat Stressors and Other Mental Health Symptoms in Iraq War Veterans

Sleep symptoms are a prominent feature of mental health disorders like PTSD and depression. However, it is unknown whether sleep symptoms mediate the relationship between combat stress and these disorders. We examined the mediating role of sleep symptoms on the relationship between combat stress and PTSD; and the relationship between combat stress and depression using data from 576 Army veterans of the Iraq War surveyed in 2004. Correlational analyses revealed that when insomnia was included in the model, the correlation between combat stressors and other depression symptoms decreased by 65%; and when nightmares were included in the model, the correlation between combat stressors and other PTSD symptoms decreased by 69%. We replicated these analyses using individual items assessing PTSD and depression and found that the insomnia and nightmare items had the largest and second largest mediation effect between combat stressors and PTSD and depression symptoms. Our result support the theory that sleep symptoms contribute to the development and/or maintenance of other mental health symptoms and that early treatment of sleep symptoms may mitigate the other mental health consequences of combat stress.     

Shifting from implicit to explicit knowledge: different roles of early- and late-night sleep

Sleep has been shown to promote the generation of explicit knowledge as indicated by the gain of insight into previously unrecognized task regularities. Here, we explored whether this generation of explicit knowledge depends on pre-sleep implicit knowledge, and specified the differential roles of slow-wave sleep (SWS) vs. rapid eye movement (REM) sleep in this process. Implicit and explicit knowledge (insight) related to a hidden regularity were assessed in an associative motor-learning task (number reduction task, NRT), which was performed in two sessions (initial practice and retest) separated by 3 h of either early-night sleep, rich in SWS, or of late-night sleep, rich in REM sleep. About half of the participants developed signs of implicit rule knowledge (i.e., speeded reaction times for responses determined by the hidden regularity) at initial practice preceding early or late sleep. Of these, half developed explicit knowledge across early-night sleep, significantly more than across late-night sleep. In contrast, late-night subjects preferentially remained on the level of implicit rule knowledge after sleep. Participants who did not develop implicit knowledge before sleep had comparable rates of transition to implicit or explicit knowledge across early and late sleep. If subjects gained explicit knowledge across sleep, this was associated with lower amounts of REM sleep, specifically in the late-night group. SWS predominant during the early night may restructure implicit memory representations in a way that allows creating an explicit representation afterward, whereas REM sleep in the late night appears to stabilize them in their implicit form.     

Psychotic symptoms in posttraumatic stress disorder

Recent data suggest that the presence of psychotic symptoms in patients suffering from posttraumatic stress disorder (PTSD) may represent an underrecognized and unique subtype of PTSD. Among combat veterans with PTSD, 30% to 40% report auditory or visual hallucinations and/or delusions. The presence of psychotic symptoms in PTSD is associated with a more severe level of psychopathology, similar to that of chronic schizophrenia. In this review, the differential diagnosis of psychotic symptoms in PTSD is discussed, including possible comorbid schizophrenia, psychotic depression, substance-induced psychosis, and personality disorder. A recent biologic study supporting the existence of a unique subtype of PTSD with psychotic features is also addressed, as are the similarities between PTSD with psychotic features and psychotic depression disorder. Finally, data on the treatment implications of psychotic symptoms in PTSD are presented. The intriguing recent findings on psychotic symptoms in PTSD need further investigation in noncombat-related PTSD populations before findings can be generalized to all individuals with PTSD.     

Change in sleep symptoms across Cognitive Processing Therapy and Prolonged Exposure: A longitudinal perspective

Sleep disturbance is a core component in posttraumatic stress disorder (PTSD). Although cognitive-behavioral treatments for PTSD reduce the severity of sleep symptoms, they do not lead to complete remission. The present study examines the impact of Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE) on subjective measures of sleep disturbance from treatment randomization through long-term follow-up (LTFU). Participants were 171 female rape victims with PTSD who were randomly assigned to CPT, PE, or Minimal Attention (MA). After 6-weeks, the MA group was randomized to CPT or PE. Sleep symptoms were assessed at baseline, post-MA, post-treatment, 3-months, 9-months and LTFU using the Pittsburgh Sleep Quality Index (PSQI) and nightmare and insomnia items from the Clinician Administered PTSD Scale. Change in sleep during MA, from pre- to post-treatment for CPT and PE, and from post-treatment through LTFU was assessed using piecewise hierarchical linear modeling with the intent-to-treat sample. Controlling for medication, sleep improved during CPT and PE compared to MA, and treatment gains were maintained through LTFU. CPT and PE were equally efficacious and improvements persist over LTFU, yet, neither produced remission of sleep disturbance. Overall, sleep symptoms do not remit and may warrant sleep-specific treatments.     

Identity Distress Among Youth Exposed to Natural Disasters: Associations with Level of Exposure,Posttraumatic Stress,and Internalizing Problems

Identity distress involves intense or prolonged upset or worry about personal identity issues including long-term goals, career choice, friendships, sexual orientation and behavior, religion, values and beliefs, and group loyalties. Research suggests that trauma exposure and subsequent posttraumatic stress disorder (PTSD) symptoms may negatively affect identity development and psychological adjustment. However, little is known about their specific associations with identity distress and internalizing problems among disaster-exposed adolescents. This study aimed to examine these associations in a sample of 325 adolescents (60% female; 89% African American) who experienced a major natural disaster and its aftermath. The results indicated that identity distress was positively associated with age, hurricane exposure, PTSD symptoms, and internalizing problems. Linear regression analyses also showed that identity distress was uniquely associated with internalizing symptoms and that there was an indirect effect of hurricane exposure on identity distress via PTSD symptoms. PTSD symptoms moderated the link between identity distress and internalizing symptoms, with a significant positive slope found for youth with more PTSD symptoms. Findings were generally consistent with previous work and predictions, and they add to the extant knowledge about identity distress by providing data on the linkages among disaster exposure, posttraumatic stress, and internalizing problems in adolescents.     

Aftermath of Violence: Posttraumatic Stress Disorder Among Vietnam Veterans

Posttraumatic stress disorder (PTSD) frequently occurs in the aftermath of violence. A comprehensive four-phase treatment approach for Vietnam veterans with PTSD is presented. Phases in the recovery process are assessment, stabilization of symptoms, working through the trauma, and reintegration into the family and society.