Attention, learning, and memory performances and intellectual resources in Vietnam veterans: PTSD and no disorder comparisons

The posttraumatic stress disorder project in Brazil: neuropsychological, structural and molecular neuroimaging studies in victims of urban violence

BACKGROUND

Life trauma is highly prevalent in the general population and posttraumatic stress disorder is among the most prevalent psychiatric consequences of trauma exposure. Brazil has a unique environment to conduct translational research about psychological trauma and posttraumatic stress disorder, since urban violence became a Brazilian phenomenon, being particularly related to the rapid population growth of its cities. This research involves three case-control studies: a neuropsychological, a structural neuroimaging and a molecular neuroimaging study, each focusing on different objectives but providing complementary information. First, it aims to examine cognitive functioning of PTSD subjects and its relationships with symptomatology. The second objective is to evaluate neurostructural integrity of orbitofrontal cortex and hippocampus in PTSD subjects. The third aim is to evaluate if patients with PTSD have decreased dopamine transporter density in the basal ganglia as compared to resilient controls subjects. This paper shows the research rationale and design for these three case-control studies.

METHODS AND DESIGN

Cases and controls will be identified through an epidemiologic survey conducted in the city of São Paulo. Subjects exposed to traumatic life experiences resulting in posttraumatic stress disorder (cases) will be compared to resilient victims of traumatic life experiences without PTSD (controls) aiming to identify biological variables that might protect or predispose to PTSD. In the neuropsychological case-control study, 100 patients with PTSD, will be compared with 100 victims of trauma without posttraumatic stress disorder, age- and sex-matched controls. Similarly, 50 cases and 50 controls will be enrolled for the structural study and 25 cases and 25 controls in the functional neuroimaging study. All individuals from the three studies will complete psychometrics and a structured clinical interview (the Structured Clinical Interview for DSM-IV and the Clinician-Administered PTSD Scale, Beck Anxiety Inventory, Beck Depression Inventory, Global Assessment of Function, The Social Adjustment Scale, Medical Outcomes Study 36-Item Short-Form Health Survey, Early Trauma Inventory, Clinical global Impressions, and Peritraumatic Dissociative Experiences Questionnaire). A broad neuropsychological battery will be administered for all participants of the neuropsychological study. Magnetic resonance scans will be performed to acquire structural neuroimaging data. Single photon emission computerized tomography with [(99m)Tc]-TRODAT-1 brain scans will be performed to evaluate dopamine transporters.

DISCUSSION

This study protocol will be informative for researchers and clinicians interested in considering, designing and/or conducting translational research in the field of trauma and posttraumatic stress disorder.

Neuropsychological performance is related to current social and occupational functioning in veterans with posttraumatic stress disorder

BACKGROUND

Several studies have reported deficits in both immediate and delayed recall of verbal memory in patients with posttraumatic stress disorder (PTSD). However, most of these studies had several methodological disadvantages. None of these studies assessed parameters related to social or occupational functioning.

METHODS

Fifty Dutch veterans of UN peacekeeping missions (25 with PTSD and 25 without PTSD) were assessed with a comprehensive neuropsychological test battery consisting of four subtests of the Wechsler Adult Intelligence Scale-III, California Verbal-Learning Test, and the Rey Auditory Verbal-Learning Test. Veterans with PTSD were free of medication and substance abuse.

RESULTS

Veterans with PTSD had similar total intelligence quotient scores compared to controls, but displayed deficits of figural and logical memory. Veterans with PTSD also performed significantly lower on measures of learning and immediate and delayed verbal memory. Memory performance accurately predicted current social and occupational functioning.

CONCLUSIONS

Deficits of memory performance were displayed in a sample of medication- and substance abuse-free veterans with PTSD. Deficits in memory performance were not related to intelligence quotient, length of trauma exposure, or time since trauma exposure. This study showed that cognitive performance accurately predicted current social and occupational functioning in veterans with PTSD.

Trauma and posttraumatic stress disorder in South African adolescents: a case-control study of cognitive deficits

Despite the prominence of neuropsychological deficits in memory, attention and learning in adults exposed to trauma and those who develop posttraumatic stress disorder (PTSD), few studies have explored these cognitive deficits in adolescents. This study aimed to assess the impact of PTSD on various neurocognitive functions in South African adolescents. In a case-control study, 40 traumatized adolescents (20 with PTSD and 20 without) were evaluated for the presence of PTSD and were then referred for neuropsychological evaluation using a standardized neuropsychological test battery. The presence of PTSD itself, rather than trauma exposure, was associated with cognitive deficiencies in attention, visual memory and nonverbal concept formation. This study highlights the impact of PTSD itself-and particularly current symptoms-on the cognitive development of adolescents. As this effect appears to be stronger than the impact of trauma alone, more studies on the long-term consequences of PTSD on youth cognitive development are crucial.

Noradrenergic and serotonergic mechanisms in the neurobiology of posttraumatic stress disorder and resilience

Posttraumatic stress disorder (PTSD) is characterized mainly by symptoms of re-experiencing, avoidance and hyperarousal as a consequence of catastrophic and traumatic events that are distinguished from ordinary stressful life events. Although extensive research has already been done, the etiology of PTSD remains unclear. Research on the impact of trauma on neurobiological systems can be expected to inform the development of treatments that are directed specifically to symptoms of PTSD. During the past 25 years there has been a dramatic increase in the knowledge about noradrenergic and serotonergic mechanisms in stress response, PTSD and more recently in resilience and this knowledge has justified the use of antidepressants with monoaminergic mechanisms of action for patients with PTSD. Nevertheless, available treatments of PTSD are only to some extent effective and enhanced understanding of the neurobiology of PTSD may lead to the development of improved treatments for these patients. In the present review, we aim to close existing gaps between basic research in psychopathology, neurobiology and treatment development with the ultimate goal to translate basic research into clinically relevant findings which may directly benefit patients with PTSD.

Neurostructural imaging findings in children with post-traumatic stress disorder: brief review

Child maltreatment has been associated with different psychiatric disorders. Studies on both animals and humans have suggested that some brain areas would be directly affected by severe psychological trauma. The pathophysiology of post-traumatic stress disorder (PTSD) appears to be related to a complex interaction involving genetic and environmental factors. Advanced neuroimaging techniques have been used to investigate neurofunctional and neurostructural abnormalities in children, adolescents, and adults with PTSD. This review examined structural brain imaging studies that were performed in abused and traumatized children, and discusses the possible biological mechanisms involved in the pathophysiology of PTSD, the implications and future directions for magnetic resonance imaging (MRI) studies. Published reports in refereed journals were reviewed by searching Medline and examining references of the articles related to structural neuroimaging of PTSD. Structural MRI studies have been performed in adults and children to evaluate the volumetric brain alterations in the PTSD population. In contrast with studies involving adults, in which hippocampus volumetric reduction was the most consistent finding, studies involving children and adolescents with PTSD have demonstrated smaller medial and posterior portions of the corpus callosum.

Verbal learning and memory impairments in posttraumatic stress disorder: the role of encoding strategies

The present study examined mechanisms underlying verbal memory impairments in patients with posttraumatic stress disorder (PTSD). Earlier studies have reported that the verbal learning and memory alterations in PTSD are related to impaired encoding, but the use of encoding and organizational strategies in patients with PTSD has not been fully explored. This study examined organizational strategies in 21 refugees/immigrants exposed to war and political violence who fulfilled DSM-IV criteria for chronic PTSD compared with a control sample of 21 refugees/immigrants with similar exposure, but without PTSD. The California Verbal Learning Test was administered to examine differences in organizational strategies and memory. The semantic clustering score was slightly reduced in both groups, but the serial cluster score was significantly impaired in the PTSD group and they also reported more items from the recency region of the list. In addition, intrusive errors were significantly increased in the PTSD group. The data support an assumption of changed memory strategies in patients with PTSD associated with a specific impairment in executive control. However, memory impairment and the use of ineffective learning strategies may not be related to PTSD symptomatology only, but also to self-reported symptoms of depression and general distress.

Changes in long term neural connectivity following psychological trauma

OBJECTIVE

Neural connectivity differences between adults reporting childhood, adulthood or no history of trauma were examined.

METHODS

A total of 39 participants completed the Post-traumatic Stress Diagnostic Scale (PDS; Foa EB. Post-traumatic Stress Diagnostic Scale (PDS) Manual. Minneapolis, MN: National Computer Systems, 1995), a Word Memory Task (WMT; [McNally RJ, Metzger LJ, Lasko NB, Clancy SA, Pitman RK. Directed forgetting of trauma cues in adult survivors of childhood sexual abuse with and without post-traumatic stress disorder. J Abnorm Psychol 1998;107:596-601]) and EEG analysis. Intelligence was not assessed during the study.

RESULTS

As predicted, those with childhood trauma had significantly higher EEG coherence than those with either adulthood trauma or no past trauma.

CONCLUSIONS

Significant differences were observed over frontal, central, temporal and parietal areas. Evidence was found suggesting that childhood psychological trauma may have a lasting impact on neuronal connectivity.

SIGNIFICANCE

This is the first study to demonstrate the suspected long term effect of trauma over central, temporal and parietal areas. Long term neural correlates of childhood and adult trauma appear to suggest information processing differences--differences that may, eventually, lead to better interventions following trauma.

Hippocampal function during associative learning in patients with posttraumatic stress disorder

In the last decade several studies have shown memory deficits in patients with posttraumatic stress disorder (PTSD) which have been associated with a reduced hippocampus volume. However, until now we do not know how or whether these structural abnormalities turn into functional abnormalities. Thus, the primary purpose of the present study was the investigation of the hippocampal function using functional magnet resonance imaging (fMRI). We compared PTSD patients and healthy control participants using an associative learning paradigm consisting of two encoding and one retrieval condition. During fMRI scanning participants had to learn face-profession pairs. Afterwards only faces were presented as cue stimuli for associating the category of the prior learned target profession and the participants had to decide whether this face belonged to a scientific or an artistic profession. Additionally, cognitive functioning, i.e. memory and attention, was examined using neuropsychological standard tests. During encoding PTSD patients showed stronger hippocampal and weaker prefrontal activation compared to healthy control participants. During retrieval the two groups did not differ neither in hippocampus activation nor in accuracy of retrieval. PTSD patients however showed a reduced activation in the left parahippocampal gyrus and other memory-related brain regions. We did not find any significant memory differences between PTSD patients and healthy control participants. The results suggest that PTSD has an effect on memory-related brain function despite intact memory functioning. In particular the hippocampal/parahippocampal regions and the prefrontal cortex show functional alterations during associative learning and memory.

The effect of failure on cognitive and psychological symptom validity tests in litigants with symptoms of post-traumatic stress disorder

This study examined the influence of performance on cognitive and psychological symptom validity tests on neuropsychological and psychological test performance in claimants evaluated in a medico-legal context (N = 301) with symptoms of PTSD. A second purpose of this study was to examine the influence of the severity of PTSD symptoms on cognitive test performance after excluding patients who failed to put forth adequate best effort and who exaggerated psychiatric symptoms. Patients were administered a battery of neuropsychological measures that were aggregated into a composite measure, the Cognitive-Test Battery Mean (C-TBM). Patients were also administered a battery of psychological tests that were aggregated into another composite measure, the Psychological-Test Battery Mean (P-TBM). We found that failure on cognitive symptom validity tests was associated with significantly poorer neuropsychological functioning, but there was not a significant effect on psychological symptoms. Conversely, failure on psychological symptom validity tests was associated with higher levels of psychopathology, but there was not a significant effect on cognitive ability. Finally, once patients were screened for adequate effort and genuine symptom reporting, the severity of PTSD symptoms did not appear to influence cognitive ability. This is the first study that assessed both types of symptom validity testing in PTSD claimants, which is important given that previous literature has demonstrated cognitive impairment in PTSD and that individuals with PTSD tend to claim cognitive impairment. Implications of these findings are discussed with regard to the existing literature and the relationship between these two types of symptom validity tests.

Consistent impaired verbal memory in PTSD: a meta-analysis

BACKGROUND

Qualitative review papers have indicated that verbal memory impairment is found to be the most consistent cognitive impairment related to PTSD. These review papers have used qualitative methods to describe the effects, and consequently they have not been able to estimate the strength of the memory-PTSD association.

METHODS

This meta-analysis of 28 studies examined the empirical evidence for this relationship, and factors affecting the results.

RESULTS

Overall, the results showed medium effect sizes in patients with PTSD compared to controls on verbal memory across studies. Marked impairment was found in the patient groups compared to healthy controls, while modest impairment was found compared to exposed non-PTSD controls. Meta-analyses found strongest effects in war veterans compared to sexual and physical assault related PTSD. Rather unexpectedly no effect was found for the sexually abused PTSD groups compared to exposed controls. The analyses further showed that the effect was dependent on the test procedures used. The studies using WMS and AVLT had stronger effects than studies using CVLT.

LIMITATIONS

Insufficient data were available to analyze a more complete attention-memory profile.

CONCLUSIONS

This meta-analysis confirms that verbal memory impairment is present in adults with PTSD, and they are consistent across studies. This impairment should be the focus of work in clinical settings.

An event-related potential study of attention deficits in posttraumatic stress disorder during auditory and visual Go/NoGo continuous performance tasks

Posttraumatic stress disorder (PTSD) is characterized by disturbances in attention, such as increased arousal and hypervigilance. This study examined the event-related potential (ERP) P3 component to target detection (Go), response inhibition (NoGo) and irrelevant nontarget stimuli during auditory and visual A-X continuous performance tasks. NoGo N2 amplitude effects were also analyzed. Participants were 23 Vietnam veterans with PTSD and 13 civilian controls. No group differences were present for N2 or P3 amplitude to Go and NoGo stimuli. The PTSD group, however, had longer P3 latency to NoGo stimuli than controls, regardless of modality. The PTSD group also had greater frontal P3 amplitude to irrelevant nontarget stimuli than controls. Significant P3 amplitude and latency findings were associated with higher hyperarousal and reexperiencing scores from the Clinician-Administered PTSD Scale. The findings suggest that attentional problems in PTSD are related to slowed central processing when response inhibition is required, and to an impaired ability to screen irrelevant information. This study provides further evidence that the attentional impairments in PTSD are not confined to trauma-related stimuli. Heightened arousal appears to enhance the attentional dysregulation seen in PTSD.

Verbal memory and treatment response in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is often associated with verbal memory deficits, which could influence treatment outcome. We assessed neuropsychological functioning in individuals with PTSD and their response to cognitive-behavioural therapy (CBT). Treatment non-responders had significantly poorer performance on measures of verbal memory compared with responders and demonstrated narrative encoding deficits. Differences were not explained by IQ, performance on tasks of attention, initial PTSD severity, depression, time since trauma, or alcohol/substance misuse. Verbal memory deficits seem to diminish the effectiveness of CBT and should be considered in its implementation.

Memory impairments in posttraumatic stress disorder are related to depression

The present study focuses on verbal learning and memory alterations in refugees with posttraumatic stress disorder, and whether the alterations are related to attention, acquisition, storage, or retrieval. Twenty-one refugees exposed to war and political violence with chronic PTSD, were compared to an exposed control sample of 21 refugees without PTSD. No differences were found in attention span, but tests of verbal memory showed less efficient learning in the PTSD sample. Group differences in delayed recall could be explained by learning efficiency. No differences were seen in recognition memory. These results indicate that memory alterations in PTSD are related to impaired acquisition and less effective encoding of the memory material and not to impaired attention span and/or impaired retrieval. Controlling for specific PTSD symptom clusters and self-reported depression showed that the intrusion subscale and depressive reactions are the most important symptoms in understanding the memory alterations in PTSD.

Does the evocation of traumatic memories confound subsequent working memory performance in posttraumatic stress disorder (PTSD)?

The role of heightened arousal has been previously discussed as a contributor to neurocognitive impairment in posttraumatic stress disorder (PTSD). To investigate whether psychological effects (distraction, re-location of resources) elicited by the evocation of traumatic memories impact on subsequent cognitive performance in PTSD, two parallel versions of a working memory task were administered to 33 trauma-exposed participants (15 with and 18 without PTSD). Between first and second working memory assessment a trauma-related interview was conducted including the narration of the trauma. Levels of working memory impairment in PTSD patients remained unchanged. This study provides preliminary evidence that neurocognitive impairment is not secondary to psychological effects induced by the evocation of traumatic memories. Nevertheless, it is recommended that future PTSD research should devote more care to the order in which trauma-related and other dependent variables such as cognitive tests are presented to participants.

Learning and memory impairment in PTSD: relationship to depression

Memory function was studied in combat veterans with posttraumatic stress disorder (PTSD), combat veterans without PTSD, and noncombat veterans. The Vocabulary and Digit Span subtests of the WAIS and Logical Memory (LMS) and Verbal Paired Associates (VPAS) subtests of the Wechsler Memory Scale III were administered. Combat veterans with PTSD showed impaired memory on the LMS and VPAS compared to combat veterans without PTSD or noncombat veterans. Veterans with PTSD also showed lower WAIS Vocabulary subtest scores--but not digit span subtest scores--than combat veterans without PTSD or noncombat veterans. Medication status, co-morbid diagnosis, and age all failed to account for these memory differences, but when self-assessed depression--as measured by the Zung Self-Rating Depression Scale--or anxiety--as measured by the Spielberger State-Trait Anxiety Scale--was statistically removed, group differences on these memory measures were no longer significant. However, using a stepwise regression procedure, in which both anxiety and depression were employed to predict the LMS and VPAS scores, only the Zung scale reliably predicated performance. The present results, showing that PTSD is associated with general learning and memory impairments, is an important finding, but the specific effects of depression as a mediator of these deficits should be further studied.

Posttraumatic stress disorder, cognitive function and quality of life in patients with schizophrenia

The purpose of the present study was to assess posttraumatic stress disorder (PTSD), cognitive function, and quality of life in patients with schizophrenia who had a self-reported history of trauma exposure. Outpatients diagnosed with schizophrenia or schizoaffective disorder were referred to the study. Each patient was assessed with the Positive and Negative Syndrome Scale (PANSS), the Harvard Trauma Questionnaire (HTQ), a cognitive assessment battery, Heinrich's Quality of Life Scale (QLS), and the Behavior and Symptom Identification Scale (BASIS). Eighty-seven subjects who reported experiencing at least one traumatic event were included in the study. Fifteen of 87 (17%) met the DSM-IV criteria for PTSD. The PTSD group had significantly worse overall cognitive performance than the non-PTSD group, especially in the domains of attention, working memory and executive function. In addition, the PTSD group showed significantly worse self-rated quality of life as measured by the BASIS total score. The development of PTSD is associated with poor cognitive function and subjectively, but not objectively, rated low quality of life in patients with schizophrenia. Evaluating PTSD in patients with schizophrenia could have important implications from both clinical and research perspectives.

Differentiating cortical patterns of cognitive dysfunction in schizophrenia and posttraumatic stress disorder

Comparative studies are needed to determine whether the cognitive impairments found in various psychiatric disorders are specific to those disorders, or are a more universal consequence of mental illness. This study compares the patterns of cognitive dysfunction in two conditions characterized by working memory dysfunction, schizophrenia and posttraumatic stress disorder (PTSD). Three matched groups (Schizophrenia, PTSD, Control) of 16 subjects had event related potentials recorded, using a 27 electrode array, while they performed a working memory auditory target detection task. Both disorders were associated with impaired task performance, with greater impairment in schizophrenia. Reduction in N1 amplitude was found only in schizophrenia, and an increase in target N2 amplitude and latency was found only in PTSD. Both patient groups showed a reduction in the amplitude of the non-target and target P3, but the groups were distinguished by a reduction in non-target parietal P3 amplitude in the schizophrenia group and a reduction in target P3 amplitude over the left posterior parietal region in the PTSD Group. This study demonstrates that there are specific patterns of cognitive dysfunction associated with schizophrenia and with PTSD.

Subtle cognitive dysfunction in nonaffected siblings of individuals affected by nonpsychotic disorders

BACKGROUND

Previous studies have reported that as a group, individuals affected by psychotic and nonpsychotic disorders perform below norms on cognitive tests. Other studies have indicated that unaffected siblings of individuals affected by psychotic disorders also perform below norms on the same tests. We investigated cognitive performance on a large, population-based sample of individuals, affected at the time of testing by nonpsychotic disorders, and their unaffected siblings.

METHODS

Subjects were taken from a population-based cohort of 523,375, 16- to 17-year-old male adolescents who had been assessed by the Israeli Draft Board. Cognitive test scores were examined in sib-pairs discordant for nonpsychotic (n = 19,489) and psychotic (n = 888) disorders and compared with 224,082 individuals from sibships with no evidence of mental illness.

RESULTS

There appears to be a gradient in cognitive performance (worst to best) from individuals currently affected by psychotic illnesses (Cohen's d = -.82), followed by individuals currently affected by nonpsychotic illness (Cohen's d = -.58), unaffected siblings of individuals affected by psychotic illness (Cohen's d = -.37), unaffected siblings of individuals affected by nonpsychotic illness (Cohen's d = -.27), and members of sibships with no evidence of mental illness. Unaffected siblings of both psychotic and nonpsychotic individuals from multiple affected sibships (more then one affected sibling) had worse cognitive test scores compared with unaffected siblings from simplex sibships (only one affected sibling).

CONCLUSIONS

The results support, but do not prove, the notion that cognitive impairment in psychiatric disorders is familial and cuts across diagnostic entities.

Neuroimaging in posttraumatic stress disorder and other stress-related disorders

Traumatic stress has a broad range of effects on the brain. Brain areas implicated in the stress response include the amygdala, the hippocampus, and the prefrontal cortex. Studies in patients who have posttraumatic stress disorder (PTSD) and other psychiatric disorders related to stress have replicated findings in animal studies by finding alterations in these brain areas. Brain regions implicated in PTSD also play an important role in memory function, highlighting the important interplay between memory and the traumatic stress response. Abnormalities in these brain areas are hypothesized to underlie symptoms of PTSD and other stress-related psychiatric disorders.

An fMRI investigation of memory encoding in PTSD: influence of symptom severity

Previous studies have shown memory deficits in Post-Traumatic Stress Disorder (PTSD) patients, as well as abnormal patterns of brain activity, especially when retrieving trauma-related information. This study extended previous findings by investigating the neural correlates of successful memory encoding of trauma-unrelated stimuli and their relationship with PTSD symptom severity. We used the subsequent memory paradigm, in the context of event-related functional magnetic resonance imaging, in 27 PTSD patients to identify the brain regions involved in the encoding of fearful and neutral faces. Symptom severity was assessed by the Clinically Administered PTSD Scale (CAPS) scores. It was found that memory performance was negatively correlated with CAPS scores. Furthermore, a negative correlation was observed between CAPS scores and ventral medial prefrontal cortex (vmPFC) activity elicited by the subsequently forgotten faces. Finally, symptom severity predicted the contribution of the amygdala to the successful encoding of fearful faces. These results confirm the roles of the vmPFC and the amygdala in PTSD and highlight the importance of taking into account individual differences when assessing the behavioural and neural correlates of the disorder.

Response variation following trauma: a translational neuroscience approach to understanding PTSD

Exposure to traumatic stress is a requirement for the development of posttraumatic stress disorder (PTSD). However, because the majority of trauma-exposed persons do not develop PTSD, examination of the typical effects of a stressor will not identify the critical components of PTSD risk or pathogenesis. Rather, PTSD represents a specific phenotype associated with a failure to recover from the normal effects of trauma. Thus, research must focus on identifying pre- and posttraumatic risk factors that explain the development of the disorder and the failure to reinstate physiological homeostasis. In this review, we summarize what is known about the clinical and biological characteristics of PTSD and articulate some of the gaps in knowledge that can be addressed by basic neuroscience research. We emphasize how knowledge about individual differences related to genetic and epigenetic factors in behavioral and brain responses to stress offers the hope of a deeper understanding of PTSD.

Chronic stress-induced hippocampal vulnerability: the glucocorticoid vulnerability hypothesis

The hippocampus, a limbic structure important in learning and memory, is particularly sensitive to chronic stress and to glucocorticoids. While glucocorticoids are essential for an effective stress response, their oversecretion was originally hypothesized to contribute to age-related hippocampal degeneration. However, conflicting findings were reported on whether prolonged exposure to elevated glucocorticoids endangered the hippocampus and whether the primate hippocampus even responded to glucocorticoids as the rodent hippocampus did. This review discusses the seemingly inconsistent findings about the effects of elevated and prolonged glucocorticoids on hippocampal health and proposes that a chronic stress history, which includes repeated elevation of glucocorticoids, may make the hippocampus vulnerable to potential injury. Studies are described to show that chronic stress or prolonged exposure to glucocorticoids can compromise the hippocampus by producing dendritic retraction, a reversible form of plasticity that includes dendritic restructuring without irreversible cell death. Conditions that produce dendritic retraction are hypothesized to make the hippocampus vulnerable to neurotoxic or metabolic challenges. Of particular interest is the finding that the hippocampus can recover from dendritic retraction without any noticeable cell loss. When conditions surrounding dendritic retraction are present, the potential for harm is increased because dendritic retraction may persist for weeks, months or even years, thereby broadening the window of time during which the hippocampus is vulnerable to harm, called the 'glucocorticoid vulnerability hypothesis'. The relevance of these findings is discussed with regard to conditions exhibiting parallels in hippocampal plasticity, including Cushing's disease, major depressive disorder (MDD), and post-traumatic stress disorder (PTSD).

Enhanced effects of cortisol administration on episodic and working memory in aging veterans with PTSD

Though both glucocorticoid alterations and memory impairments have been noted in posttraumatic stress disorder (PTSD), it is not clear if these phenomena are causally linked. As there is emerging evidence that these domains become further altered in PTSD with increasing age, it is of interest to examine these relationships in an older cohort. Aging (mean age, 62.7+/-8.9; range, 52-81) combat veterans with (n=13) and without (n=17) PTSD received an intravenous bolus of 17.5 mg hydrocortisone (cortisol), a naturally occurring glucocorticoid, or placebo in a randomized, double-blind manner, on two mornings approximately 1-2 weeks apart. Neuropsychological testing to evaluate episodic and working memory performance was performed 75 min later. Cortisol enhanced episodic memory performance in both groups of subjects, but enhanced elements of working memory performance only in the PTSD+ group. The preferential effect of cortisol administration on working memory in PTSD may be related to the superimposition of PTSD and age, as cortisol had impairing effects on this task in a previously studied, younger cohort. The findings suggest that there may be opportunities for developing therapeutic strategies using glucocorticoids in the treatment of aging combat veterans.

Configural cue performance in identical twins discordant for posttraumatic stress disorder: theoretical implications for the role of hippocampal function

BACKGROUND

A significant subgroup of individuals with posttraumatic stress disorder (PTSD) exhibits chronic, unremitting symptomatology that has also been associated with smaller hippocampal volume. The hippocampus plays a significant role in configural processing of contextual cues that facilitates context-appropriate extinction of conditioned fear. We test the hypothesis that hippocampus-based configural processing deficits are a pre-existing vulnerability factor for unremitting forms of PTSD.

METHODS

Participants included male monozygotic twin pairs who were discordant for combat trauma. In 18 twin pairs the combat-exposed brother developed unremitting PTSD, whereas in 23 pairs the combat-exposed brother never developed PTSD. Participants were compared in the capacity to solve allocentric spatial processing tasks, and this performance was examined for its relationship to the severity of PTSD symptomatology and hippocampal volume.

RESULTS

Although not completely differentiated from overall IQ, PTSD combat veterans demonstrated significantly impaired performance in configural processing relative to non-PTSD combat veterans. Despite having neither combat-exposure nor PTSD, the unexposed co-twins of combat veterans with PTSD displayed the same decrements as their brothers. Deficits were significantly related to PTSD severity and hippocampal volume.

CONCLUSIONS

The current study provides the first evidence that the relevance of the hippocampus in PTSD might be related to pre-existing configural cue processing deficits that predispose individuals to develop unremitting forms of the disorder.

Detection of malingered PTSD: an overview of clinical, psychometric, and physiological assessment: where do we stand?

Posttraumatic stress disorder (PTSD) is a condition that can be easily malingered for secondary gain. For this reason, it is important for physicians to understand the phenomenology of true PTSD and indicators that suggest an individual is malingering. This paper reviews the prevalence of PTSD for both the general population and for specific events, such as rape and terrorism, to familiarize evaluators with the frequency of its occurrence. The diagnostic criteria for PTSD, as well as potential ambiguities in the criteria, such as what constitutes an exposure to a traumatic event, are reviewed. Identified risk factors are reviewed as a potential way to help differentiate true cases of PTSD from malingered cases. The question of symptom overreporting as a feature of the disease versus a sign of malingering is discussed. We then examine how the clinician can use the clinical interview (e.g., SIRS, CAPS), psychometric testing, and the patient's physiological responses to detect malingering. Particular attention is paid to research on the MMPI and the subscales of infrequency (F), infrequency-psychopathology (Fp), and infrequency-posttraumatic stress disorder (Fptsd). Research and questions regarding the accuracy of self-report questionnaires, specifically the Mississippi Scale (MSS) and the Personality Assessment Inventory (PAI), are examined. Validity, usability, and cutoff values for other psychometric tests, checklists, and physiological tests are discussed. The review includes a case, which shows how an individual used symptom checklist information to malinger PTSD and the inconsistencies in his story that the evaluator detected. We conclude with a discussion regarding future diagnostic criteria and suggestions for research, including a systematic multifaceted approach to identify malingering.

Executive deficits in chronic PTSD related to political violence

Twenty-two subjects with chronic PTSD were compared to 23 subjects with no diagnoses (NPD) on tests of executive functioning (EF) that are assumed to have clinical significance after exposure to political violence.

METHOD

The three cognitive components of EF, intentionality, inhibition and executive memory [Burgess, P. W., Alderman, N., Evans, J., Emslie, H., Wilson, B. A. (1998). The ecological validity of tests of executive function. Journal of the International Neuropsychological Society, 4, 547-58], were measured using the Tower of London, Stroop Color-Word Test and Wisconsin Card Sorting Test (WCST), respectively.

RESULTS

The PTSD group was impaired on tasks measuring automatic processing and executive memory. Executive memory problems were related to elevated posttraumatic symptoms, but the executive components intentionality and inhibition did not differentiate the groups. Arousal and intrusive symptoms had no impact on intentionality.

CONCLUSION

Posttraumatic symptoms are related to automatic processing problems and impairment in executive memory. Observed dysfunctions in mental flexibility could have a negative impact on the cognitive processing of traumatic memory, thus preventing from recovery.

Everyday attention lapses and memory failures: the affective consequences of mindlessness

We examined the affective consequences of everyday attention lapses and memory failures. Significant associations were found between self-report measures of attention lapses (MAAS-LO), attention-related cognitive errors (ARCES), and memory failures (MFS), on the one hand, and boredom (BPS) and depression (BDI-II), on the other. Regression analyses confirmed previous findings that the ARCES partially mediates the relation between the MAAS-LO and MFS. Further regression analyses also indicated that the association between the ARCES and BPS was entirely accounted for by the MAAS-LO and MFS, as was that between the ARCES and BDI-II. Structural modeling revealed the associations to be optimally explained by the MAAS-LO and MFS influencing the BPS and BDI-II, contrary to current conceptions of attention and memory problems as consequences of affective dysfunction. A lack of conscious awareness of one's actions, signaled by the propensity to experience brief lapses of attention and related memory failures, is thus seen as having significant consequences in terms of long-term affective well-being.

Traumatic stress: effects on the brain

Brain areas implicated in the stress response include the amygdala, hippocampus, and prefrontal cortex. Traumatic stress can be associated with lasting changes in these brain areas. Traumatic stress is associated with increased cortisol and norepinephrine responses to subsequent stressors. Antidepressants have effets on the hippocampus that counteract the effects of stress. Findings from animal studies have been extended to patients with post-traumatic stress disorder (PTSD) showing smaller hippocampal and anterior cingulate volumes, increased amygdala function, and decreased medial prefrontal/anterior cingulate function. In addition, patients with PTSD show increased cortisol and norepinephrine responses to stress. Treatments that are efficacious for PTSD show a promotion of neurogenesis in animal studies, as well as promotion of memory and increased hippocampal volume in PTSD.

PTSD psychiatric patients exhibit a deficit in remembering

This study investigated the effects of PTSD on levels of awareness in a recognition memory task. A group of PTSD psychiatric patients and a control group without any traumatic experience were compared in remembering (R) versus knowing (K) recognition using non-trauma-related words. Results showed that overall recognition did not differ between the two groups, but in the PTSD group a significantly different pattern of Remember and Know responses was produced, indicating a shift from remembering to knowing. However, this shift from remembering to knowing in individuals with PTSD is associated with modifications in the trait anxiety level. These results are interpreted within theoretical frameworks in which R responses could be associated with distinctiveness (Rajaram, 1996) and conceptual processing (Ehlers & Clark, 2000). These collective findings would suggest the possibility that a poor general ability in the formation of source memory may eventually be a common characteristic across different types of PTSD.

Posttraumatic stress disorder: memory and learning performance in children and adolescents

BACKGROUND

Despite the wealth of information in adult posttraumatic stress disorder (PTSD) literature, few studies have explored the memory and learning performance of trauma-exposed youth. This study examined if memory deficits are associated with PTSD or with trauma exposure in the absence of PTSD.

METHODS

Youth exposed to traumatic incidents underwent clinical interviews to diagnose PTSD and exclude major comorbid disorders. Youth with conditions that could impede performance on a memory scale (e.g., limited intellectual functioning, current substance abuse, psychopharmacological treatment) were excluded. Three groups of participants were identified (PTSD positives [n = 29], traumatized PTSD negatives [n = 62], and nontraumatized control subjects [n = 40]). Participants completed the Wide Range Assessment of Memory and Learning (WRAML).

RESULTS

Youth with PTSD evidenced significantly lower scores on the WRAML General Memory, Verbal Memory, and Learning indices compared with nontraumatized control subjects. With the exception of Verbal Memory, youth with and without PTSD performed comparably on all other indices. Nonsignificant differences were noted on the Visual Memory Index.

CONCLUSIONS

General memory and verbal memory impairments as evidenced in adult populations were observed among this sample of youth. Given the developmental trajectory of memory capabilities, the implications of such early trauma exposure and memory deficits are considered.

Brain responses to symptom provocation and trauma-related short-term memory recall in coal mining accident survivors with acute severe PTSD

Functional neuroimaging studies have largely been performed in patients with longstanding chronic posttraumatic stress disorder (PTSD). Additionally, memory function of PTSD patients has been proved to be impaired. We sought to characterize the brain responses of patients with acute PTSD and implemented a trauma-related short-term memory recall paradigm. Individuals with acute severe PTSD (n=10) resulting from a mining accident and 7 men exposed to the mining accident without PTSD underwent functional magnetic resonance imaging (fMRI) while performing the symptom provocation and trauma-related short-term memory recall paradigms. During symptom provocation paradigm, PTSD subjects showed diminished responses in right anterior cingulate gyrus, left inferior frontal gyrus and bilateral middle frontal gyrus and enhanced left parahippocampal gyrus response compared with controls. During the short-term memory recall paradigm, PTSD group showed diminished responses in right inferior frontal gyrus, right middle frontal and left middle occipital gyrus in comparison with controls. PTSD group exhibited diminished right parahippocampal gyrus response during the memory recall task as compared to the symptom provocation task. Our findings suggest that neurophysiological alterations and memory performance deficit have developed in acute severe PTSD.

Pilot trial of memantine in the treatment of posttraumatic stress disorder

This multiple case series was initially designed as a prospective, open-label, 12-week trial investigation evaluating memantine (Namenda) for the treatment of psychiatric and cognitive symptoms associated with PTSD. In a selected, small sample of individuals (n = 4) with combat PTSD, treatment with memantine produced consistent improvement on a delayed recall measure of memory, variable reduction of depressive symptoms, and variable reduction in hyperarousal symptoms. These data suggest potential positive treatment outcomes, both cognitively and psychiatrically, and provide rationale for future double-blind, placebo-controlled studies of memantine in PTSD.

Structural and functional plasticity of the human brain in posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is associated with long-term changes in neurobiology. Brain areas involved in the stress response include the medial prefrontal cortex, hippocampus, and amygdala. Neurohormonal systems that act on the brain areas to modulate PTSD symptoms and memory include glucocorticoids and norepinephrine. Dysfunction of these brain areas is responsible for the symptoms of PTSD. Brain imaging studies show that PTSD patients have increased amygdala reactivity during fear acquisition. Other studies show smaller hippocampal volume. A failure of medial prefrontal/anterior cingulate activation with re-experiencing of the trauma is hypothesized to represent a neural correlate of the failure of extinction seen in PTSD. The brain has the capacity for plasticity in the aftermath of traumatic stress. Antidepressant treatments and changes in environment can reverse the effects of stress on hippocampal neurogenesis, and humans with PTSD showed increased hippocampal volume with both paroxetine and phenytoin.

Is posttraumatic stress disorder associated with specific deficits in episodic memory?

People with PTSD often report difficulties remembering day to day information unrelated to their traumatic episode. In addition, structural and functional imaging techniques have identified abnormalities in the brains of people with PTSD in regions known to be important for memory functioning. Nevertheless, studies investigating cognitive functioning in people with PTSD have reported widely varying results. The aim of this review is to investigate studies reporting performance on tests of episodic memory. Specifically, papers were examined in relation to the hypothesised memory functions of the frontal lobes, the hippocampus and the amygdala. It is concluded that while there is reasonable evidence of frontal lobe involvement, memory deficits caused by hippocampal involvement have been more difficult to detect. There are no published studies looking at the involvement of the amygdala although preliminary evidence suggests that people with PTSD do have memory deficits resulting from dysfunction of this structure. Reasons for the inconclusiveness of the results are discussed.

Neuropsychological functioning in posttraumatic stress disorder and alcohol abuse

Studies have shown differences in neuropsychological functioning between groups with posttraumatic stress disorder (PTSD) and control participants. Because individuals with PTSD often have a history of comorbid alcohol abuse, the extent to which an alcohol confound is responsible for these differences remains a concern. The current study compares neuropsychological testing scores in 4 groups of veterans with and without PTSD (PTSD+ and PTSD-, respectively) and with and without a history of alcohol abuse (ETOH+ and ETOH-, respectively): n for PTSD+/ETOH- = 30, n for PTSD+/ETOH- = 37, n for PTSD-/ETOH+ = 30, and n for PTSD-/ETOH- = 31. Results showed that PTSD, when alcohol, educational level, vocabulary, and depression are controlled for, was associated with decreased verbal memory, attention, and processing speed performance. Alcohol abuse history was associated with decreased visual memory performance. By controlling for alcohol and depression, the authors can more conclusively demonstrate that verbal memory and attention differences are associated with PTSD.

Longitudinal assessment of cognitive performance in Holocaust survivors with and without PTSD

BACKGROUND

There are currently no longitudinal studies of cognitive performance in older patients with Posttraumatic Stress Disorder (PTSD). It is therefore unclear whether relationships between memory and symptoms differ over time among older persons with and without PTSD.

METHODS

Twenty-eight Holocaust survivors and nineteen comparison subjects were evaluated 5 years after they had received a memory assessment including paired-associates learning and the California Verbal Learning Test (CVLT).

RESULTS

While Holocaust survivors with PTSD showed a diminution in symptom severity (t = 2.99, df = 12, p = .011), they still manifested a decline in paired associates learning, suggesting an acceleration in age-related memory impairment (related word pairs: t = 2.87, df = 13, p = .013; unrelated word pairs: t = 2.06, df = 13, p = .060). The survivors with PTSD showed improvements on several CVLT measures over time. These improvements correlated with symptom improvements, such that group differences at the follow-up were no longer detected.

CONCLUSIONS

The discrepancy in the pattern of performance on these two tests of memory following symptom improvement suggests possible differentiation between of aspects of memory functions associated with aging and trauma exposure and those associated with the severity of PTSD symptoms. Performance on the CVLT appeared related to clinical symptom severity while paired associate learning worsened over time in Holocaust survivors with PTSD, consistent with earlier cross-sectional findings.

Neurocognitive function in monozygotic twins discordant for combat exposure: relationship to posttraumatic stress disorder

Neuropsychological deficits have been reported among trauma survivors with posttraumatic stress disorder (PTSD). It is often assumed that these cognitive difficulties are toxic consequences of trauma exposure. Alternatively, they may reflect preexisting characteristics that contribute to the likelihood of developing PTSD. To address this possibility, the authors evaluated cognitive performance in monozygotic twin pairs who were discordant for combat exposure. Pairs were grouped according to whether the combat-exposed brother developed PTSD. The combat-unexposed cotwins of combat veterans with PTSD largely displayed the same performance as their brothers, which was significantly lower than that of non-PTSD combat veterans and their brothers. The results support the notion that specific domains of cognitive function may serve as premorbid risk or protective factors in PTSD.

Memory performance in older trauma survivors: implications for the longitudinal course of PTSD

Impaired declarative memory performance and smaller hippocampal volume have been observed in young and middle-aged adults with chronic posttraumatic stress disorder (PTSD). These alterations may put trauma survivors with PTSD at greater risk for cognitive decline in later life. This article focuses on the emerging literature on neuropsychological impairment in aging trauma survivors, in particular, elderly combat veterans and survivors of the Holocaust. In veterans and in Holocaust survivors, PTSD was associated with substantial impairments in learning, free and cued recall, and recognition memory compared to the respective nonexposed subjects; however, in neither group was PTSD associated with impaired retention or "rapid forgetting." Additionally, PTSD was not associated with smaller right or left hippocampal volume in either cohort. PTSD is associated with considerable cognitive burden with age. Longitudinal studies of older subjects are warranted to examine whether PTSD is associated with accelerated aging or progressive memory loss.

IQ and posttraumatic stress symptoms in children exposed to interpersonal violence

BACKGROUND

The literature is mixed as to the relationship between intelligence quotient (IQ) and Posttraumatic Stress Disorder (PTSD) symptomatology in adult populations. Even less is known about the relationship in children who have been traumatized.

METHODS

Fifty-nine children and adolescents (mean age = 10.6) with a history of interpersonal violence were evaluated with respect to PTSD symptomatology, number of traumas, and estimated Verbal, Performance and Full scale IQ scores. PTSD symptomatology included symptom levels for cluster B (re-experiencing), cluster C (avoidance and numbing), and cluster D (Hypervigilance) and criterion F, functional impairment.

RESULTS

Results indicated that Full scale and Verbal IQ were significantly associated with the number of traumas, re-experiencing symptoms, and impairment. Performance IQ was only associated with impairment. Regression analyses suggested that together PTSD symptomatology predicted Full scale and Verbal IQ but nor Performance IQ and impairment was the single best predictor of IQ generally.

CONCLUSIONS

Findings provide support for an association between PTSD symptoms and IQ, particularly verbal IQ. Two possible reasons for this relationship are that higher levels of Verbal IQ may serve as a premorbid protective factor against the development of re-experiencing symptoms, or performance on post-trauma Verbal IQ measures may be negatively impacted by expression of PTSD symptoms. Longitudinal studies are needed to clarify which of these two possibilities explains the association.

The relationship between cognitive and brain changes in posttraumatic stress disorder

Preclinical studies show that stress is associated with changes in structure of the hippocampus, a brain area that plays a critical role in memory, inhibition of neurogenesis, and memory deficits. Studies in animals showed that both serotonin reuptake inhibitors (SSRIs) and the epilepsy medication phenytoin (dilantin) block the effects of stress on the hippocampus. Imaging studies in posttraumatic stress disorder (PTSD) have found smaller volume of the hippocampus as measured with magnetic resonance imaging (MRI) in patients with PTSD related to both combat and childhood abuse. These patients were also found to have deficits in memory on neuropsychological testing. Functional imaging studies using positron emission tomography (PET) found decreased hippocampal activation with memory tasks. In an initial study, we found that a year of treatment with paroxetine led to a 5% increase in hippocampal volume and a 35% increase in memory function. A second study showed that phenytoin was efficacious for symptoms of PTSD and led to a significant 6% increase in both right hippocampal and right whole brain volume, with no significant change in memory. These studies suggest that medications may counteract the effects of stress on the brain in patients with PTSD.

The impact of the 1991 Gulf War on the mind and brain: findings from neuropsychological and neuroimaging research

Many veterans of the 1991 Gulf War (GW) have complained of somatic and cognitive symptoms that may be neurological in nature. However, whether or not changes in brain function are associated with GW service continues to be debated. Studies of GW veterans using objective, performance-based neuropsychological measures have yielded inconsistent findings, with those indicating deficits among GW veterans typically revealing only relatively mild levels of neuropsychological impairment. Further, performances on objective neuropsychological tasks show little correspondence to subjective perceptions of cognitive functioning. Although preliminary magnetic resonance spectroscopy (MRS) studies demonstrate reduced N-acetylaspartate-to-creatine (NAA/Cr) ratio in select brain regions among GW veterans who report health concerns, this work requires further replication with larger, more representative samples. There is no evidence from neuroimaging studies of a non-specific effect of GW service or of changes in brain structure or function related to health status when conventional radiological methods are used. Owing to the paucity of objective exposure, baseline health data, and the now significant time elapsed since the GW, aetiological issues may never be fully resolved. Therefore, research addressing clinical management of GW veterans with neuropsychological dysfunction and neuroimaging abnormalities may prove more fruitful than exclusive focus on aetiology.

Meta-analytic review of event-related potential studies in post-traumatic stress disorder

In recent years there has been an accumulation of studies that have utilized the measurement of event-related potentials (ERP) to examine the neuroelectric correlates of hypothesized alterations in information processing in persons with post-traumatic stress disorder (PTSD). The objective of this meta-analysis was to summarize the findings of ERP PTSD research, including studies that have examined P50 auditory sensory gating, augmenting-reducing P200, and P300 in target detection oddball tasks. The results suggest that persons with PTSD exhibit alterations in the amplitude and latency of ERP within these paradigms that support the hypothesis that changes in information processing can accompany PTSD. The results were also consistent with recent cognitive neuropsychological findings in PTSD research.

A systematic and conceptual review of posttraumatic stress in childhood cancer survivors and their parents

Recent years have witnessed a rapid acceleration in the recognition and documentation of posttraumatic stress disorder (PTSD) and posttraumatic stress symptomatology (PTSS) in childhood cancer survivors and their parents. However, applicability of PTSD both diagnostically and conceptually to cancer-related traumatic responses remains poorly articulated within the current literature. Following an outline of childhood cancer and PTSD, this paper critically examines the applicability of such a diagnosis to this clinical population. It then systematically reviews the current evidence base (24 studies) on PTSD and PTSS in childhood cancer survivors and their parents. Prevalence of PTSD and PTSS, as well as associated predictors, in this clinical population varies widely. Findings are considered in the light of a number of contemporary theories of PTSD. Limitations within current conceptualizations of PTSD are highlighted with respect to the nature of cancer as a traumatic event and the specific features of traumatic stress manifestations in childhood cancer survivors and their parents. Finally, a number of pertinent research areas are elucidated which are argued to warrant further investigation.

Cortisol, learning, memory, and attention in relation to smaller hippocampal volume in police officers with posttraumatic stress disorder

BACKGROUND

A proposed explanation for memory impairments in posttraumatic stress disorder (PTSD) is stress-induced hippocampal damage due to elevated cortisol levels. We have previously reported smaller hippocampi in police officers with PTSD. In this study, we examined changes in and associations between cortisol, learning, memory, attention, and hippocampal volume in PTSD.

METHODS

In a case-matched control study, 12 police officers with PTSD and 12 traumatized police officers without lifetime PTSD were examined with magnetic resonance imaging (for hippocampal volume), salivary cortisol tests, and neurocognitive assessments.

RESULTS

Significantly smaller hippocampi and higher early morning salivary cortisol levels were found in PTSD. Subjects with PTSD performed worse on a delayed visual memory recall task at trend level, and made more perseverations and intrusions on a verbal memory task. Negative correlations were found between PTSD symptom severity and immediate recall function, and between re-experiencing symptoms and left hippocampal volume. A positive correlation was found between salivary cortisol level in early morning and right hippocampal volume; however, hippocampal volume did not correlate with memory.

CONCLUSIONS

Smaller hippocampi, higher cortisol levels, and memory impairments were associated with PTSD but were not directly correlated to one another. Memory impairments in PTSD do not seem to be a direct consequence of hippocampal size.

Disaster-related posttraumatic stress symptoms and sustained attention: evaluation of depressive symptomatology and sleep disturbances as mediators

Research about attentional functioning following trauma has almost exclusively been performed in patient populations with combat-related posttraumatic stress disorder (PTSD). In this study the relationship between sustained attention and PTSD symptoms was examined in a community sample of survivors of a major disaster using the Paced Auditory Serial Addition Task (PASAT) and the Self-Rating Scale for PTSD (SRS-PTSD) 2-3 years postdisaster. Analyses revealed low but significant partial correlations between PTSD symptoms and the least difficult subtests, ruling out the effects of age, education, depressive symptomatology, and sleep disturbances. These results demonstrate that PTSD symptoms link to attentional dysfunction 2-3 years postdisaster.