Implicit and explicit memory for trauma-related information in PTSD

[Trauma and literality: psychodynamic reason in the spirit of neuroscientific traumatization]

Since its origin in the surgical medicine of the 17th century, trauma research has had multiple interpretations and has been associated either with visible injuries to organs and tissues, or with the influence of pathogenic psychic agents on memory, consciousness and personality. With the intensification of the role of classification systems since DSM-III, the phenomenon of trauma came to be incorporated into the psychiatric realm through Post-Traumatic Stress Disorder and destined finally to the constraints of neuroscientific research. Based on a narrative review, this article will address one of the fundamental epistemological premises for this transition, which informs how psychological trauma gained autonomy over anatomical descriptions to be reclassified, around a century later, as an essentially bodily phenomenon and incorporated into the jargon of neurosciences.

A proof-of-concept randomized crossover clinical trial of a first-in-class vasopressin 1a receptor antagonist for PTSD: Design, methods, and recruitment

Background

Almost eight million Americans suffer from Posttraumatic Stress Disorder (PTSD). Current PTSD drug therapies rely on repurposed antidepressants and anxiolytics, which produce undesirable side effects and have recognized compliance issues. Vasopressin represents a promising and novel target for pharmacological intervention. Logistical issues implementing a clinical trial for a novel PTSD pharmaceutical are relatively uncharted territory as trials concerning a new agent have not been published in the past several decades. All published trials have repurposed FDA-approved psychoactive medications with known risk profiles. Our recruitment challenges are discussed in this context.

Methods

An 18-week proof-of-concept randomized crossover clinical trial of a first-in-class vasopressin 1a receptor antagonist (SRX246) for PTSD was conducted. All participants received SRX246 for 8 weeks, the placebo for 8 weeks, and the drug vs. placebo arms were compared. Participants were assessed every 2 weeks for PTSD symptoms as well as other medication effects. Results were expected to provide an initial demonstration of safety and tolerability in this clinical population and potentially clinical efficacy in SRX246-treated patients measured by Clinician Administered PTSD Scale (CAPS) score changes, clinical impression, and other indices compared to placebo. The primary hypothesis was that SRX246 would result in a clinically meaningful 10-point reduction in mean CAPS score compared to placebo.

Discussion

This study is the first to investigate an oral vasopressin 1a receptor antagonist for PTSD. As a wave of PTSD clinical trials with new pharmaceutical compounds are beginning now, lessons learned from our recruitment challenges may be invaluable to these endeavors.

[The sovereignty of the visible: how traumatic memory becomes traumatic stress]

Since the release of the third version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), biological psychiatry has been systematically applying its classification reasoning to social phenomena of many natures. From this perspective, the discourse of trauma gained relevance and events of devastating magnitude began to receive neurobehavioral interpretations until finally being recognized less for their cultural and subjective effects than for the physiological changes they cause. By a narrative review, this study aims to analyze the transition of traumatic rationality from the 19th century, when trauma was associated with the cognitive concept of memory, to the 20th century, when this phenomenon was finally attached to neuroscientific research on stress. The plurality of conceptual models and deterministic paradigms can contribute to the fact that trauma research produces multifactorial coping protocols more appropriate to the human experience of post-traumatic suffering.

Impaired episodic memory in PTSD patients - A meta-analysis of 47 studies

Episodic memory impairments beyond the traumatic event might be a characteristic hallmark of post-traumatic stress disorder (PTSD). Although several studies support such a claim, empirical findings are inconsistent. Therefore, we performed a random-effects meta-analysis including data from a total of 47 studies and 3,062 subjects. As main finding, we can show that PTSD patients show episodic memory deficits compared to all controls. This effect was significantly stronger for PTSD vs. non-traumatized healthy controls as compared to PTSD vs. traumatized controls without PTSD. Finally, episodic memory impairments in PTSD were most pronounced in verbal memory tests as compared to non-verbal memory tests. Our results provide new evidence that PTSD is characterized by impaired episodic long-term memory beyond the traumatic event, and these deficits are particularly pronounced in verbal memory. We will discuss our findings in the context of physiological, psychological and trauma related memory models. From a broader perspective, our findings may have implications for the treatment of PTSD by suggesting that the assessment and, if necessary, training of memory deficits could be included as part of diagnostics and psychotherapeutic treatment.

Mechanisms Underlying Unconscious Processing and Their Alterations in Post-traumatic Stress Disorder: Neuroimaging of Zero Monetary Outcomes Contextually Framed as "No Losses" vs. "No Gains"

Although unconscious processing is a key element of mental operation, its neural correlates have not been established. Also, clinical observations suggest that unconscious processing may be involved in the pathophysiology of post-traumatic stress disorder (PTSD), but the neurobiological mechanisms underlying such impairments remain unknown. The purpose of the present study was to examine putative mechanisms underlying unconscious processing by healthy participants and to determine whether these mechanisms may be altered in PTSD patients. Twenty patients with PTSD and 27 healthy individuals were administered a validated wheel of fortune-type gambling task during functional magnetic resonance imaging (fMRI). Unconscious processing was elicited using unconscious contextual framing of the zero monetary outcomes as "no loss," "no gain" or as "neutral." Brief passive visual processing of the "no loss" vs. "no gain" contrast by healthy participants yielded bilateral frontal-, temporal- and insular cortices and striatal activations. Between-group comparison revealed smaller activity in the left anterior prefrontal-, left dorsolateral prefrontal-, right temporal- and right insular cortices and in bilateral striatum in PTSD patients with the left dorsolateral prefrontal cortex activity been more pronounced in those with greater PTSD severity. These observations implicate frontal-, temporal-, and insular cortices along with the striatum in the putative mechanisms underlying unconscious processing of the monetary outcomes. Additionally, our results support the hypothesis that PTSD is associated with primary cortical and subcortical alterations involved in the above processes and that these alterations may be related to some aspects of PTSD symptomatology.

The Impact of Psychological Interventions on Posttraumatic Stress Disorder and Pain Symptoms: A Systematic Review and Meta-Analysis

OBJECTIVES

Posttraumatic stress disorder (PTSD) and pain often co-occur, introducing clinical challenges and economic burden. Psychological treatments are considered effective for each condition, yet it is not known which therapies have the potential to concurrently address PTSD and pain-related symptoms.

MATERIALS AND METHODS

To conduct a systematic review and meta-analysis, databases were searched for articles published between January 2007 and December 2017 describing results from clinical trials of interventions addressing PTSD and pain-related symptoms in adults. Two independent reviewers finalized data extraction and risk of bias assessments. A random-effects model was used for meta-analysis and to calculate pooled and subgroup effect sizes (ESs) of psychological-only (single modality) and multimodal interventions.

RESULTS

Eighteen trials (7 uncontrolled, 11 randomized controlled trials, RCTs), totaling 1583 participants, were included in the systematic review. RCT intervention types included exposure-based, cognitive-behavioral, and mindfulness-based therapies. Data from 10 RCTs (N=1, 35) were available for meta-analysis, which demonstrated moderate effect for reduced PTSD severity (ES=-0.55, confidence interval [CI]: -0.83, -0.26) and nonsignificant effect for pain intensity (ES=-0.14, CI: -0.43, 0.15) and pain interference (ES=-0.07, CI: -0.35, 0.20) outcomes. Findings from uncontrolled trials supported meta-analytic results from RCTs. Using GRADE assessment, the quality of evidence was deemed as moderate for RCTs and low for non-RCTs.

DISCUSSION

Findings indicated that the majority of the interventions appeared to have a greater impact on reducing PTSD rather than pain-related symptoms. There remains a need to further develop interventions that consistently impact PTSD and pain-related outcomes when these 2 conditions co-occur.

Emotional Memory in Post-traumatic Stress Disorder: A Systematic PRISMA Review of Controlled Studies

Background: Emotional memory is an adaptive process that improves the memorization of emotional events or stimuli. In Post-Traumatic Stress Disorder (PTSD), emotional memory may be altered, which in turn may affect symptoms. Having a clearer view of the processes of interaction between memory and emotional stimuli in PTSD may improve our knowledge of this disorder, and could create new therapeutic management tools. Thus, we performed a systematic review of the evidence of specific emotional memory in PTSD patients.

Method: Following PRISMA guidelines, a systematic review of MEDLINE, PsycInfo, and ScienceDirect was undertaken to identify controlled studies on emotional memory that used cognitive tasks on PTSD patients. The initial research was conducted from June 2017 to July 2017, and search terms included: Post-Traumatic Stress Disorder; PTSD; emotional memory; emotion; emotional; memory; and episodic memory.

Results: Eighteen studies reporting on 387 PTSD patients met the eligibility criteria. Among the studies selected, 11 observed specific memory processing in PTSD patients, such as a greater memorization of negative information, or a trend to false recognition of negative information. In addition, attentional and inhibition processing seem to play an important role in emotional memory in PTSD sufferers. Furthermore, other studies that did not find behavioral differences between PTSD and control groups nevertheless showed differences in both specific cerebral activities and neurohormone levels during emotional memory tasks.

Conclusion: This review has several limitations, including a limited number of controlled studies, small sample sizes, different tasks and methods. Nevertheless, the results of this systematic review provide interesting information on emotional memory for clinicians and researchers, as they seem to highlight facilitated memory processing for negative information in PTSD patients. This topic needs further controlled studies with sensitive behavioral tasks. Also, future studies may evaluate emotional memory after symptom amelioration.

Vagus nerve stimulation promotes generalization of conditioned fear extinction and reduces anxiety in rats

BACKGROUND

Exposure-based therapies are used to treat a variety of trauma- and anxiety-related disorders by generating successful extinction following cue exposure during treatment. The development of adjuvant strategies that accelerate extinction learning, improve tolerability, and increase efficiency of treatment could increase the efficacy of exposure-based therapies. Vagus nerve stimulation (VNS) paired with exposure can enhance fear extinction, in rat models of psychiatric disorders, and chronic administration of VNS reduces anxiety in rats and humans.

OBJECTIVE

We tested whether VNS, like other cognitive enhancers, could produce generalization of extinction for stimuli that are not presented during the extinction sessions, but are associated with the fear event.

METHODS

Male Sprague Dawley rats underwent auditory fear conditioning with two easily discriminable auditory stimuli. Following fear conditioning, extinction training consisted of exposure to only one of the conditioned sounds. Half of the rats received VNS and half received sham stimulation during with sound presentations. VNS effects on anxiety were examined in a separate study where VNS was administered prior to testing on the elevated plus maze.

RESULTS

Sham stimulated rats given 20 presentations of a conditioned stimulus (CS) during the extinction session showed performance that was matched to VNS-treated rats given only 4 presentations of the CS. Despite comparable levels of freezing to the presented CS, only the VNS-treated rats showed a significant decrease in freezing to the CS that was not presented. VNS-induced generalization of extinction was observed only when the two sounds were paired with footshock within the same fear conditioning session; VNS did not promote generalization of extinction when the two sounds were conditioned on different days or in different contexts. On the anxiety test, VNS administration significantly increased time spent in the open arms of the elevated plus maze.

CONCLUSION

These results provide evidence that VNS can promote generalization of extinction to other stimuli associated with a specific fear experience. Furthermore, non-contingent VNS appears to reduce anxiety. The ability to generalize extinction and reduce anxiety makes VNS a potential candidate for use as an adjunctive strategy to improve the efficacy and tolerability of exposure-based therapies.

Using New Approaches in Neurobiology to Rethink Stress-Induced Amnesia

Purpose of Review

Psychological stress can impact memory systems in several different ways. In individuals with healthy defense and coping systems, stress results in the formation of negatively valenced memories whose ability to induce emotional and somatic distress subsides with time. Vulnerable individuals, however, go on to develop stress-related disorders such as post-traumatic stress disorder (PTSD) and suffer from significant memory abnormalities. Whether expressed as intrusive trauma memories, partial amnesia, or dissociative amnesia, such abnormalities are thought to be the core source of patients' symptoms, which are often debilitating and implicate an entire socio-cognitive-affective spectrum.

Recent Findings

With this in mind, and focusing on stress-responsive hippocampal microcircuits, this article highlights recent advances in the neurobiology of memory that allow us to (1) isolate and visualize memory circuits, (2) change their activity using genetic tools and state-dependent manipulations, and (3) directly examine their impact on socio-affective circuits and global network connectivity. By integrating these approaches, we are now in a position to address important questions that have troubled psychiatry for a long time-questions such as are traumatic memories special, and why are stress effects on memory diverse.

Summary

Furthering our fundamental understanding of memory in the framework of adaptive and maladaptive stress responses has the potential to boost the development of new treatments that can benefit patients suffering from psychological trauma.

Weak evidence for increased motivated forgetting of trauma-related words in dissociated or traumatised individuals in a directed forgetting experiment

Motivated forgetting is the idea that people can block out, or forget, upsetting or traumatic memories, because there is a motivation to do so. Some researchers have cited directed forgetting studies using trauma-related words as evidence for the theory of motivated forgetting of trauma. In the current article subjects used the list method directed forgetting paradigm with both trauma-related words and positive words. After one list of words was presented subjects were directed to forget the words previously learned, and they then received another list of words. Each list was a mix of positive and trauma-related words, and the lists were counterbalanced. Later, subjects recalled as many of the words as they could, including the ones they were told to forget. Based on the theory that motivated forgetting would lead to recall deficits of trauma-related material, we created eight hypotheses. High dissociators, trauma-exposed, sexual trauma-exposed, and high dissociators with trauma-exposure participants were hypothesised to show enhanced forgetting of trauma words. Results indicated only one of eight hypotheses was supported: those higher on dissociation and trauma recalled fewer trauma words in the to-be-forgotten condition, compared to those low on dissociation and trauma. These results provide weak support for differential motivated forgetting.

Neural correlates of experimental trauma memory retrieval

OBJECTIVES

Traumatic memories such as intrusions and flashbacks play a major role in the development and maintenance of post-traumatic stress disorder (PTSD). A thorough understanding of the neural mechanisms underlying traumatic memories is indispensable for precise diagnosis, for personalized treatment and prevention. In particular, the identification of early neural predictor variables for intrusion development shortly after trauma exposure requires detailed investigation.

EXPERIMENTAL DESIGN

Here, we examined the neural correlates of early experimental trauma memory retrieval in a traumatic film paradigm in 42 young healthy females, using both implicit and explicit retrieval tasks.

PRINCIPAL OBSERVATIONS

We show that implicit experimental trauma retrieval specifically involved the retrosplenial cortex and the anterior cingulate cortex (ACC), while both retrieval tasks resulted in trauma-related activity in the posterior cingulate cortex (PCC) and the precuneus. Importantly, neural activity early after experimental trauma exposure predicted later intrusion development, with independent contributions from activity in the retrosplenial cortex (implicit retrieval) and the PCC (explicit retrieval). Additional analyses revealed a stronger connectivity between the bilateral amygdala and the supplementary motor area, precentral and paracentral lobule for the control group compared to the experimental trauma group.

CONCLUSIONS

Our study gives new insights in the neural correlates of experimental trauma memory retrieval and their predictive value for subsequent symptom development. Our results could provide the basis for personalized early treatment and prevention of PTSD. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc. Hum Brain Mapp 38:3592-3602, 2017. © 2017 Wiley Periodicals, Inc.

Patterns of Childhood Abuse and Neglect in a Representative German Population Sample

BACKGROUND

Different types of childhood maltreatment, like emotional abuse, emotional neglect, physical abuse, physical neglect and sexual abuse are interrelated because of their co-occurrence. Different patterns of childhood abuse and neglect are associated with the degree of severity of mental disorders in adulthood. The purpose of this study was (a) to identify different patterns of childhood maltreatment in a representative German community sample, (b) to replicate the patterns of childhood neglect and abuse recently found in a clinical German sample, (c) to examine whether participants reporting exposure to specific patterns of child maltreatment would report different levels of psychological distress, and (d) to compare the results of the typological approach and the results of a cumulative risk model based on our data set.

METHODS

In a cross-sectional survey conducted in 2010, a representative random sample of 2504 German participants aged between 14 and 92 years completed the Childhood Trauma Questionnaire (CTQ). General anxiety and depression were assessed by standardized questionnaires (GAD-2, PHQ-2). Cluster analysis was conducted with the CTQ-subscales to identify different patterns of childhood maltreatment.

RESULTS

Three different patterns of childhood abuse and neglect could be identified by cluster analysis. Cluster one showed low values on all CTQ-scales. Cluster two showed high values in emotional and physical neglect. Only cluster three showed high values in physical and sexual abuse. The three patterns of childhood maltreatment showed different degrees of depression (PHQ-2) and anxiety (GAD-2). Cluster one showed lowest levels of psychological distress, cluster three showed highest levels of mental distress.

CONCLUSION

The results show that different types of childhood maltreatment are interrelated and can be grouped into specific patterns of childhood abuse and neglect, which are associated with differing severity of psychological distress in adulthood. The results correspond to those recently found in a German clinical sample and support a typological approach in the research of maltreatment. While cumulative risk models focus on the number of maltreatment types, the typological approach takes the number as well as the severity of the maltreatment types into account. Thus, specific patterns of maltreatment can be examined with regard to specific long-term psychological consequences.

Patterns of childhood abuse and neglect as predictors of treatment outcome in inpatient psychotherapy: a typological approach

BACKGROUND

Childhood maltreatment is associated with the development and maintenance of mental disorders. The purpose of this naturalistic study was (a) to identify different patterns of childhood maltreatment, (b) to examine how these patterns are linked to the severity of mental disorders and (c) whether they are predictive of treatment outcome.

METHODS

742 adult patients of a university hospital for psychotherapy and psychosomatics were assessed at intake and discharge by standardized questionnaires assessing depression (Beck Depression Inventory, BDI) and general mental distress (Symptom Check List-90-R, SCL-90-R). Traumatic childhood experience (using the Childhood Trauma Questionnaire, CTQ) and ICD-10 diagnoses were assessed at intake.

RESULTS

The patients could be allocated to three different patterns of early childhood trauma experience: mild traumatization, multiple traumatization without sexual abuse and multiple traumatization with sexual abuse. The three patterns showed highly significant differences in BDI, General Severity Index (GSI) and in the number of comorbidity at intake. For both BDI and GSI a general decrease in depression and general mental distress from intake to discharge could be shown. The three patterns differed in BDI and GSI at intake and discharge, indicating lowest values for mild traumatization and highest values for multiple traumatization with sexual abuse. Patients with multiple traumatization with sexual abuse showed the least favourable outcome.

CONCLUSION

The results provide evidence that the severity of childhood traumatization is linked to the severity of mental disorders and also to the treatment outcome in inpatient psychotherapy. In the study, three different patterns of childhood traumatization (mild traumatization, multiple traumatization without sexual abuse, multiple traumatization with sexual abuse) showed differences in the severity of mental disorder and in the course of treatment within the same therapy setting.

Current status on behavioral and biological markers of PTSD: a search for clarity in a conflicting literature

Extensive research has identified stereotypic behavioral and biological abnormalities in post-traumatic stress disorder (PTSD), such as heightened autonomic activity, an exaggerated startle response, reduced basal cortisol levels and cognitive impairments. We have reviewed primary research in this area, noting that factors involved in the susceptibility and expression of PTSD symptoms are more complex and heterogeneous than is commonly stated, with extensive findings which are inconsistent with the stereotypic behavioral and biological profile of the PTSD patient. A thorough assessment of the literature indicates that interactions among myriad susceptibility factors, including social support, early life stress, sex, age, peri- and post-traumatic dissociation, cognitive appraisal of trauma, neuroendocrine abnormalities and gene polymorphisms, in conjunction with the inconsistent expression of the disorder across studies, confounds attempts to characterize PTSD as a monolithic disorder. Overall, our assessment of the literature addresses the great challenge in developing a behavioral and biomarker-based diagnosis of PTSD.

Emotion regulation modulates anticipatory brain activity that predicts emotional memory encoding in women

It has been shown that the effectiveness with which unpleasant events are encoded into memory is related to brain activity set in train before the events. Here, we assessed whether encoding-related activity before an aversive event can be modulated by emotion regulation. Electrical brain activity was recorded from the scalps of healthy women while they performed an incidental encoding task on randomly intermixed unpleasant and neutral visual scenes. A cue presented 1.5 s before each picture indicated the upcoming valence. In half of the blocks of trials, the instructions emphasized to let emotions arise in a natural way. In the other half, participants were asked to decrease their emotional response by adopting the perspective of a detached observer. Memory for the scenes was probed 1 day later with a recognition memory test. Brain activity before unpleasant scenes predicted later memory of the scenes, but only when participants felt their emotions and did not detach from them. The findings indicate that emotion regulation can eliminate the influence of anticipatory brain activity on memory encoding. This may be relevant for the understanding and treatment of psychiatric diseases with a memory component.

Natural memory beyond the storage model: repression, trauma, and the construction of a personal past

Naturally occurring memory processes show features which are difficult to investigate by conventional cognitive neuroscience paradigms. Distortions of memory for problematic contents are described both by psychoanalysis (internal conflicts) and research on post-traumatic stress disorder (PTSD; external traumata). Typically, declarative memory for these contents is impaired - possibly due to repression in the case of internal conflicts or due to dissociation in the case of external traumata - but they continue to exert an unconscious pathological influence: neurotic symptoms or psychosomatic disorders after repression or flashbacks and intrusions in PTSD after dissociation. Several experimental paradigms aim at investigating repression in healthy control subjects. We argue that these paradigms do not adequately operationalize the clinical process of repression, because they rely on an intentional inhibition of random stimuli (suppression). Furthermore, these paradigms ignore that memory distortions due to repression or dissociation are most accurately characterized by a lack of self-referential processing, resulting in an impaired integration of these contents into the self. This aspect of repression and dissociation cannot be captured by the concept of memory as a storage device which is usually employed in the cognitive neurosciences. It can only be assessed within the framework of a constructivist memory concept, according to which successful memory involves a reconstruction of experiences such that they fit into a representation of the self. We suggest several experimental paradigms that allow for the investigation of the neural correlates of repressed memories and trauma-induced memory distortions based on a constructivist memory concept.

Cognition and depression: current status and future directions

Cognitive theories of depression posit that people's thoughts, inferences, attitudes, and interpretations, and the way in which they attend to and recall information, can increase their risk for depression. Three mechanisms have been implicated in the relation between biased cognitive processing and the dysregulation of emotion in depression: inhibitory processes and deficits in working memory, ruminative responses to negative mood states and negative life events, and the inability to use positive and rewarding stimuli to regulate negative mood. In this review, we present a contemporary characterization of depressive cognition and discuss how different cognitive processes are related not only to each other, but also to emotion dysregulation, the hallmark feature of depression. We conclude that depression is characterized by increased elaboration of negative information, by difficulties disengaging from negative material, and by deficits in cognitive control when processing negative information. We discuss treatment implications of these conclusions and argue that the study of cognitive aspects of depression must be broadened by investigating neural and genetic factors that are related to cognitive dysfunction in this disorder. Such integrative investigations should help us gain a more comprehensive understanding of how cognitive and biological factors interact to affect the onset, maintenance, and course of depression.

Stress effects on working memory, explicit memory, and implicit memory for neutral and emotional stimuli in healthy men

Stress is a strong modulator of memory function. However, memory is not a unitary process and stress seems to exert different effects depending on the memory type under study. Here, we explored the impact of social stress on different aspects of human memory, including tests for explicit memory and working memory (for neutral materials), as well as implicit memory (perceptual priming, contextual priming and classical conditioning for emotional stimuli). A total of 35 young adult male students were randomly assigned to either the stress or the control group, with stress being induced by the Trier Social Stress Test (TSST). Salivary cortisol levels were assessed repeatedly throughout the experiment to validate stress effects. The results support previous evidence indicating complex effects of stress on different types of memory: A pronounced working memory deficit was associated with exposure to stress. No performance differences between groups of stressed and unstressed subjects were observed in verbal explicit memory (but note that learning and recall took place within 1 h and immediately following stress) or in implicit memory for neutral stimuli. Stress enhanced classical conditioning for negative but not positive stimuli. In addition, stress improved spatial explicit memory. These results reinforce the view that acute stress can be highly disruptive for working memory processing. They provide new evidence for the facilitating effects of stress on implicit memory for negative emotional materials. Our findings are discussed with respect to their potential relevance for psychiatric disorders, such as post traumatic stress disorder.

Acute episodes of predator exposure in conjunction with chronic social instability as an animal model of post-traumatic stress disorder

People who are exposed to horrific, life-threatening experiences are at risk for developing post-traumatic stress disorder (PTSD). Some of the symptoms of PTSD include persistent anxiety, exaggerated startle, cognitive impairments and increased sensitivity to yohimbine, an alpha(2)-adrenergic receptor antagonist. We have taken into account the conditions known to induce PTSD, as well as factors responsible for long-term maintenance of the disorder, to develop an animal model of PTSD. Adult male Sprague-Dawley rats were administered a total of 31 days of psychosocial stress, composed of acute and chronic components. The acute component was a 1-h stress session (immobilization during cat exposure), which occurred on Days 1 and 11. The chronic component was that on all 31 days the rats were given unstable housing conditions. We found that psychosocially stressed rats had reduced growth rate, reduced thymus weight, increased adrenal gland weight, increased anxiety, an exaggerated startle response, cognitive impairments, greater cardiovascular and corticosterone reactivity to an acute stressor and heightened responsivity to yohimbine. This work demonstrates the effectiveness of acute inescapable episodes of predator exposure administered in conjunction with daily social instability as an animal model of PTSD.

Information Processing Bias in Post-traumatic Stress Disorder

This review considers theory and evidence for abnormal information processing in post-traumatic stress disorder (PTSD). Cognitive studies have indicated sensitivity in PTSD for traumatic information, more so than general emotional information. These findings were supported by neuroimaging studies that identify increased brain activity during traumatic cognition, especially in affective networks (including the amygdala, orbitofrontal and anterior cingulate cortex). In theory, it is proposed that traumatic cognition may interfere with neutral cognition and there is evidence of abnormal neutral stimulus processing in PTSD. Firstly, PTSD patients perform poorly on a variety of neuropsychology tasks that involve attention and memory for neutral information. The evidence from event-related potentials and functional neuroimaging also indicates abnormal results in PTSD during neutral stimulus processing. The research evidence generally provides support for theories of trauma sensitivity and abnormal neutral stimulus processing in PTSD. However, there is only tentative evidence that trauma cognition concurrently interferes with neutral cognition. There is even some evidence that traumatic or novelty arousal processes can increase the capacity for attentive processing, thereby enhancing cognition for neutral stimulus information. Research on this topic has not yet fully explored the mechanisms of interaction between traumatic and neutral content in the cognitive dynamics of PTSD.

Emotional memory function, personality structure and psychopathology: a neural system approach to the identification of vulnerability markers

It is well established that emotional events are ingrained stronger into memory relative to neutral events. Facilitated emotional memory is highly variable between individuals within the normal population and is particularly exacerbated in those diagnosed with mood and anxiety disorders. In order to elucidate how variation of enhanced emotional memory within the normal population may manifest into psychopathological states, we explored the convergence between studies investigating the neural systems engaged in emotional memory facilitation and studies investigating how these systems differ from person to person. Converging evidence highlights the roles of three neural systems (1. Amygdala function and attention, 2. Neuroendocrine function, 3. Interactive effects with mood) that all govern emotional memory facilitation and are highly variable between individuals as a function of personality. We applied this neural system approach to models of vulnerability of three forms of psychopathology that are particularly characterized by atypical emotional memory function (depression, generalized anxiety disorder and post-traumatic stress disorder). This application suggests that the incorporation of known vulnerability markers across psychological, neuroimaging and neuroendocrinological domains is cardinal to how susceptibility is conceptualized and assessed in these disorders.

Sexual desire and linguistic analysis: a comparison of sexually-abused and non-abused women

Although studies have identified a relationship between a history of child sexual abuse (CSA) and problems with hypoactive sexual desire, little is known about the potential cognitive and affective mechanisms involved in the sexual desire of women with a history of CSA. In this study, 27 women with a history of CSA and 22 women with no history of abuse were asked to write about sexual and non sexual topics. The Linguistic Inquiry Word Count software program was used to compute the percentage of words that fell into positive emotions, negative emotions, body, and sex categories. As expected, women with a history of CSA used more negative emotions words when writing about sexual topics, but not non-sexual topics, compared to non-abused women. Women with a history of CSA also used more sex words when writing about the non-sexual topics compared to non-abused women. Frequencies of body and sex words used in the sexual texts were positively linked to levels of sexual desire function. This association was not different between women with and without a history of CSA. A history of CSA remained an independent predictor of levels of sexual desire dysfunction even when taking into consideration the language used in the sexual texts, indicating that there may be aspects of the sexual desire experienced by women with a history of CSA that differ from non-abused women that remain unexplored.

Steroid pregnenolone sulfate enhances NMDA-receptor-independent long-term potentiation at hippocampal CA1 synapses: Role for L-type calcium channels and sigma-receptors

Severe stress elevates plasma and CNS levels of endogenous neuroactive steroids that can contribute to the influence of stress on memory formation. Among the neuroactive steroids, pregnenolone sulfate (PREGS) reportedly strengthens memories and is readily available as a memory-enhancing supplement. PREGS actions on memory may reflect its ability to produce changes in memory-related neuronal circuits, such as long-term potentiation (LTP) of excitatory transmission in hippocampus. Here, we report a previously undiscovered pathway by which PREGS exposure promotes activity-dependent LTP of field excitatory postsynaptic potentials at CA1 synapses in hippocampal slices. Thus, application of PREGS, but not the phosphated conjugate of the steroid, selectively facilitates the induction of a slow-developing LTP in response to high-frequency (100 Hz) afferent stimulation, which is not induced in the absence of the steroid. The slow-developing LTP is independent of NMDA-receptor function (i.e., dAP5 insensitive) but dependent on functional L-type voltage-gated calcium channels (VGCC) and sigma-receptors. By contrast, PREGS at the highest concentration tested produces a depression in NMDA-receptor-dependent LTP, which is evident when sigma-receptor function is compromised by the presence of a sigma-receptor antagonist. We found that at early times during the induction phase of L-type VGCC-dependent LTP, PREGS via sigma-receptors transiently enhances presynaptic function. As well, during the maintenance phase of L-type VGCC-dependent LTP, PREGS promotes a further increase in presynaptic function downstream of LTP induction, as evidenced by a decrease in paired-pulse facilitation. The identification of complex regulatory actions of PREGS on LTP, involving sigma-receptors, L-type VGCCs, NMDA-receptors, and inhibitory circuits will aid future research endeavors aimed at understanding the precise mechanisms by which this stress-associated steroid may engage multiple LTP-signaling pathways that alter synaptic transmission at memory-related synapses.

Directed forgetting in PTSD: a comparative study versus normal controls

The most characteristic feature of Post-Traumatic Stress Disorder (PTSD) is the reexperiencing syndrome. The patient's memory seems to be fixed on the traumatic event, which may be due to disturbance of the autobiographic memory. To retrieve memories, others have to be inhibited. These inhibition mechanisms have been studied using the Directed Forgetting Paradigm, which measures the capacity to forget recently processed information and to retain the relevant information. Our hypothesis is that during PTSD, the memory is saturated with traumatic memories, so that the patients are no longer able to use the inhibitory processes. Therefore, during a Directed Forgetting Task (DFT) in which words "to remember" and words "to forget" are given, PTSD patients cannot inhibit the words "to forget", and so recall more words than the controls. We studied 30 patients with PTSD and compared them with 30 healthy controls, using DFT. The results show that the patients remembered significantly fewer words overall, and fewer of the words "to remember" than the controls, both for immediate and final recall. Our results are in favor of a reduction in directed forgetting in patients suffering from PTSD, resulting in difficulty in inhibiting irrelevant information from the overall information. There seems to be a deficit in the inhibitory processes in the memory in PTSD.

Differential time courses and specificity of amygdala activity in posttraumatic stress disorder subjects and normal control subjects

BACKGROUND

Previous neuroimaging studies have demonstrated exaggerated amygdala responses to negative stimuli in posttraumatic stress disorder (PTSD). The time course of this amygdala response is largely unstudied and is relevant to questions of habituation and sensitization in PTSD exposure therapy.

METHODS

We applied blood oxygen level dependent functional magnetic resonance imaging and statistical parametric mapping to study amygdala responses to trauma-related and nontrauma-related emotional words in sexual/physical abuse PTSD and normal control subjects. We examined the time course of this response by separate analysis of early and late epochs.

RESULTS

PTSD versus normal control subjects have a relatively increased initial amygdala response to trauma-related negative, but not nontrauma-related negative, versus neutral stimuli. Patients also fail to show the normal patterns of sensitization and habituation to different categories of negative stimuli. These findings correlate with measured PTSD symptom severity.

CONCLUSIONS

Our results demonstrate differential time courses and specificity of amygdala response to emotional and control stimuli in PTSD and normal control subjects. This has implications for pathophysiologic models of PTSD and treatment response. The results also extend previous neuroimaging studies demonstrating relatively increased amygdala response in PTSD and expand these results to a largely female patient population probed with emotionally valenced words.

Stress doses of hydrocortisone, traumatic memories, and symptoms of posttraumatic stress disorder in patients after cardiac surgery: a randomized study

BACKGROUND

Traumatic experiences associated with cardiac surgery (CS) can result in traumatic memories and posttraumatic stress disorder (PTSD). Because it is known that subjects who develop PTSD often show sustained reductions in circulating cortisol concentrations, we performed a prospective, randomized study to examine whether exogenously administered stress doses of hydrocortisone during the perioperative period of CS reduces the long-term incidence of chronic stress and PTSD symptoms.

METHODS

Patients (n = 91) were prospectively randomized to receive either stress doses of hydrocortisone or standard treatment during the perioperative period of CS. Of 48 available patients at 6 months after CS, 26 had received stress doses of hydrocortisone and 22 standard treatment. Traumatic memories and PTSD symptoms were diagnosed with previously validated questionnaires.

RESULTS

As compared with patients after standard therapy, patients from the hydrocortisone group had significantly lower chronic stress symptom scores (p <.05). There was no significant difference regarding the number or type of traumatic memories between the hydrocortisone and the standard treatment groups.

CONCLUSIONS

Stress doses of hydrocortisone in patients undergoing CS are associated with a lower intensity of chronic stress and PTSD symptoms at 6 months after CS.

Memory for trauma-related information in Holocaust survivors with PTSD

The impact of trauma-related information on memory performance in aging Holocaust survivors with post-traumatic stress disorder (PTSD) was evaluated. Explicit and implicit memory for neutral and Holocaust-related words was assessed in Holocaust survivors with PTSD (PTSD+, n=31), in Holocaust survivors without PTSD (PTSD-, n=17), and in healthy Jewish adults not exposed to the Holocaust (non-exposed, n=34) using the paired associates learning and word-stem completion tests, respectively. The PTSD+ group had significantly poorer paired associate recall than the PTSD- and non-exposed groups, and showed a significantly different response to the introduction of Holocaust-related words. The PTSD+ group recalled significantly more words from the Holocaust-related than the neutral word pairs, whereas word type had little effect on paired associate recall in the other two groups. In contrast, there were no group differences in implicit memory performance or in the effect of Holocaust-related words on implicit memory. Among Holocaust survivors, explicit recall of Holocaust-related word pairs was associated with intrusive PTSD symptoms. These results suggest that aging Holocaust survivors with PTSD preferentially form new associations with trauma-related stimuli as compared with neutral stimuli. The presence of such a disturbance of associative learning decades after the Holocaust may underlie the persistence of psychological symptoms and, in particular, the intrusive symptoms of PTSD. This trauma-related facilitation of explicit memory, together with generally poorer explicit memory, may help to explain the bi-directional nature of the memory impairments in PTSD.

Circuits and systems in stress. II. Applications to neurobiology and treatment in posttraumatic stress disorder

This paper follows the preclinical work on the effects of stress on neurobiological and neuroendocrine systems and provides a comprehensive working model for understanding the pathophysiology of posttraumatic stress disorder (PTSD). Studies of the neurobiology of PTSD in clinical populations are reviewed. Specific brain areas that play an important role in a variety of types of memory are also preferentially affected by stress, including hippocampus, amygdala, medial prefrontal cortex, and cingulate. This review indicates the involvement of these brain systems in the stress response, and in learning and memory. Affected systems in the neural circuitry of PTSD are reviewed (hypothalamic-pituitary-adrenal axis (HPA-axis), catecholaminergic and serotonergic systems, endogenous benzodiazepines, neuropeptides, hypothalamic-pituitary-thyroid axis (HPT-axis), and neuro-immunological alterations) as well as changes found with structural and functional neuroimaging methods. Converging evidence has emphasized the role of early-life trauma in the development of PTSD and other trauma-related disorders. Current and new targets for systems that play a role in the neural circuitry of PTSD are discussed. This material provides a basis for understanding the psychopathology of stress-related disorders, in particular PTSD.

The effect of being a victim or witness of family violence on the retrieval of autobiographical memories

OBJECTIVE

This study was designed to determine whether greater reliance on general memory retrieval in children was related to depression, and whether family violence affected the specificity of children's memory retrieval.

METHOD

We compared children who had experienced some form of family violence with children who had never experienced any form of family violence, based on their responses to questions concerning child-parent and interparental disagreements.

RESULTS

As expected, there was a positive correlation between the extent of "generic-categoric" memory retrieval and depression level. There was no evidence, however, that autobiographical memory was affected by family violence.

CONCLUSIONS

This study is the first to report significant associations between depression and autobiographical memory style in children. The results suggest that the effect of family violence on children's memory retrieval may be mediated by depression.

Memory, attention, function, and mood among patients with chronic posttraumatic stress disorder

We report a study of memory, attention, function, and mood among 36 male Vietnam War Veterans suffering from chronic posttraumatic stress disorder (PTSD). PTSD subjects (N = 36) were in good physical health, suffering from moderate depression, and not knowingly suffering from other mental disorders. Control subjects (N = 18) were in good physical health, not knowingly suffering from a mental disorder, and matched with PTSD subject for age, sex, and level of education. Assessment instruments for PTSD subjects included the PostTraumatic Stress Diagnostic Scale (clinician administered), the Hamilton Depression Rating Scale (clinician administered), and the Cognitive Evaluation Protocol (CEP), a touchscreen computer assessment instrument that is self-administered by subjects. CEP was administered twice to PTSD subjects 1 month apart; other instruments were administered at the beginning of the study. Control subjects took CEP once and were administered the Hamilton Depression Rating Scale and the PostTraumatic Stress Diagnostic Scale once. Compared with control subjects, PTSD subjects performed significantly less well on CEP for the three cognitive domains of attention, memory, and function and had highly elevated depression scores. An interaction between depression and memory was found but not with depression and attention. There was no evidence of reduced information processing speed among PTSD subjects. Comparisons between the three assessment instruments showed a high degree of cross-assessment agreement. The findings are consistent with reports that chronic PTSD is associated with compromised memory, attention, and function. The study documents the feasibility of using self-administrated touchscreen computer programs to evaluate and track features of mental disorders.