Peritraumatic dissociation and physiological response to trauma-relevant stimuli in Vietnam combat veterans with posttraumatic stress disorder

A recent study found that female rape victims with acute posttraumatic stress disorder (PTSD) who received a high score on the Peritraumatic Dissociative Experiences Questionnaire exhibited suppression of physiological responses during exposure to trauma-related stimuli. The goal of our present study was to test whether the same relationship holds true for male Vietnam combat veterans with chronic PTSD, using secondary analyses applied to data derived from a Veteran's Affairs Cooperative Study. Vietnam combat veterans (N = 1238) completed measures to establish combat-related PTSD diagnostic status, extent of PTSD-related symptomatic distress, and presence of dissociative symptoms during their most stressful combat-related experiences. Extreme subgroups of veterans with current PTSD were classified as either low dissociators (N = 118) or high dissociators (N = 256) based on an abbreviated version of the Peritraumatic Dissociative Experiences Questionnaire. Dependent variables reflected subjective distress along with heart rate, skin conductance, electromyographic, and blood pressure data when responding to neutral and trauma-related audiovisual and imagery presentations. Veterans in the current PTSD group had significantly higher dissociation scores than did veterans in the lifetime and never PTSD groups. Among veterans with current PTSD, high dissociators reported greater PTSD-related symptomatic distress than did low dissociators, but the groups did not differ with respect to physiological reactivity to the trauma-related laboratory presentations. Our results replicate the previously reported relationship between peritraumatic dissociation and PTSD status in Vietnam combat veterans. However, we found no association between peritraumatic dissociation and the extent of physiological responding to trauma-relevant cues in male veterans with chronic combat-related PTSD.     

Global-local visual processing in posttraumatic stress disorder.

The purpose of this study was to examine a behavioral index of hemispheric asymmetry (i.e., visual hierarchical attention) in posttraumatic stress disorder (PTSD), a disorder characterized by anxiety and other emotional symptoms. A reaction time based, computerized, global-local visual paradigm was administered to 26 PTSD-diagnosed and 22 psychopathology-free right-handed, male Vietnam War zone veterans. Results indicated that PTSD-diagnosed veterans displayed slower reaction times to all targets than the no-mental disorders comparison sample. However, findings also revealed a Group x Target location interaction in which the PTSD group was slower than the no-disorders comparison sample to respond to local, but not global, targets. Moreover, relative global bias was greater among PTSD-diagnosed veterans than their no-diagnosis counterparts. Findings provide partial support for the hypothesis that PTSD may be associated with a functional cerebral asymmetry favoring the right hemisphere.     

Altered pain processing in veterans with posttraumatic stress disorder

CONTEXT: Posttraumatic stress disorder (PTSD) is a chronic and debilitating anxiety disorder. Several brain areas related to pain processing are implicated in PTSD. To our knowledge, no functional imaging study has discussed whether patients with PTSD experience and process pain in a different way than control subjects. OBJECTIVE: To examine neural correlates of pain processing in patients with PTSD. DESIGN: The experimental procedure consisted of psychophysical assessment and neuroimaging with functional magnetic resonance imaging. Two conditions were assessed during functional magnetic resonance imaging in both experimental groups, one condition with administration of a fixed temperature of 43 degrees C (fixed-temperature condition) and the other condition with an individual temperature for each subject but with a similar affective label equaling 40% of the subjective pain intensity (individual temperature condition). SETTING: Academic outpatient unit in a department of military psychiatry in collaboration with an imaging center at a psychiatric hospital. PARTICIPANTS: Twelve male veterans with PTSD and 12 male veterans without PTSD were recruited and matched for age, region of deployment, and year of deployment. MAIN OUTCOME MEASURES: Changes in functional magnetic resonance imaging blood oxygenation level-dependent response to heat stimuli, reflecting increased and decreased activity of brain areas involved in pain processing. RESULTS: Patients with PTSD rated temperatures in the fixed-temperature assessment as less painful compared with controls. In the fixed-temperature condition, patients with PTSD revealed increased activation in the left hippocampus and decreased activation in the bilateral ventrolateral prefrontal cortex and the right amygdala. In the individual temperature condition, patients with PTSD showed increased activation in the right putamen and bilateral insula, as well as decreased activity in the right precentral gyrus and the right amygdala. CONCLUSIONS: These data provide evidence for reduced pain sensitivity in PTSD. The witnessed neural activation pattern is proposed to be related to altered pain processing in patients with PTSD.     

Corticolimbic blood flow during nontraumatic emotional processing in posttraumatic stress disorder

CONTEXT: Recent brain imaging studies implicate dysfunction of limbic and paralimbic circuitry, including the amygdala and medial prefrontal cortex (MPFC), in the pathogenesis of posttraumatic stress disorder (PTSD) during traumatic recollection and imagery. However, the relationship between activity in these regions and general emotional processing unrelated to traumatic experience has not been fully examined. OBJECTIVE: To investigate activity in the limbic and paralimbic brain regions in PTSD in response to a challenge with emotionally salient generic visual images. DESIGN: Cross-sectional, case-control study. SETTING: Academic medical center. PARTICIPANTS: Sixteen Vietnam veterans with combat-related PTSD (PTSD group), 15 combat-exposed Vietnam veterans without PTSD (combat control group), and 15 age- and sex-matched healthy controls (normal control group). MAIN OUTCOME MEASURES: We used positron emission tomography to study regional cerebral blood flow while participants viewed complex visual pictures with negatively valenced/aversive, nonaversive ("neutral"), and blank pictures. Psychophysiologic and emotional self-report data were also recorded. RESULTS: All 3 groups activated the dorsal MPFC to general salient content. Controls without PTSD activated the left amygdala in response to aversive stimuli. Normal controls activated the ventral MPFC and combat-exposed non-PTSD and PTSD participants exhibited either no response or deactivation in these regions, respectively, during negative emotional experience. CONCLUSIONS: Consistent with current functional neuroanatomic models, patients with PTSD exhibited altered neural responses in the amygdala and ventral MPFC during the processing of emotionally salient but trauma-unrelated stimuli, potentially reflecting disorder-specific changes. Activation of the amygdala and lack of ventral MPFC deactivation to negatively valenced images in combat controls may reflect compensatory changes after trauma exposure that are not associated with PTSD.     

An electrocortical investigation of emotional face processing in military-related posttraumatic stress disorder

PTSD is a disorder of emotion dysregulation. Although much work has intended to elucidate the neural underpinnings of the disorder, much remains unknown about the neurobiological substrates of emotion dysregulation in PTSD. In order to assess the relationship between a neural measure of attention to emotion (i.e. the late positive potential; LPP) and PTSD symptoms, EEG was recorded and examined as a potential predictor of military-related PTSD symptoms in a sample of 73 OEF/OIF/OND veterans. Results revealed that higher PTSD symptoms were related to an attenuated LPP response to angry facial expressions. This finding was not observed for happy or fearful faces. The current study provides initial evidence that, in a relatively young, mostly male sample of OEF/OIF/OND veterans, hyporeactivity to angry faces at the neural level may provide phenotypic data to characterize individual differences in PTSD symptom severity. This work may assist in future studies that seek to examine useful psychophysiologic targets for treatment and early interventions.     

Rumination in posttraumatic stress disorder

Recent studies have shown that rumination is a powerful predictor of persistent posttraumatic stress disorder (PTSD). However, to date, the mechanisms by which rumination maintains PTSD symptoms are little understood. Two studies of assault survivors, a cross-sectional (N = 81) and a 6-month prospective longitudinal study (N = 73), examined several facets of ruminative thinking to establish which aspects of rumination provide the link to PTSD. The current investigation showed that rumination is not only used as a strategy to cope with intrusive memories but it also triggers such memories. Certain characteristics of rumination, such as compulsion to continue ruminating, occurrence of unproductive thoughts, and "why" and "what if" type questions, as well as negative emotions before and after rumination, were significantly associated with PTSD, concurrently and prospectively. These characteristics explained significantly more variance in PTSD severity than the mere presence of rumination, thereby indicating that not all ways of ruminative thinking are equally maladaptive.     

Working memory processing of traumatic material in women with posttraumatic stress disorder

Background

Posttraumatic stress disorder (PTSD) is associated with medial frontal and amygdala functional alterations during the processing of traumatic material and frontoparietal dysfunctions during working memory tasks. This functional magnetic resonance imaging (fMRI) study investigated the effects of trauma-related words processing on working memory in patients with PTSD.

Methods

We obtained fMRI scans during a 3-back task and an identity task on both neutral and trauma-related words in women with PTSD who had been sexually abused and in healthy, nonexposed pair-matched controls.

Results

Seventeen women with PTSD and 17 controls participated in the study. We found no behavioural working memory deficit for the PTSD group. In both tasks, deactivation of posterior parietal midline regions was more pronounced in patients than controls. Additionally, patients with PTSD recruited the left dorsolateral frontal sites to a greater extent during the processing of trauma-related material than neutral material.

Limitations

This study included only women and did not include a trauma-exposed non-PTSD control group; the results may, therefore, have been influenced by sex or by effects specific to trauma exposure.

Conclusion

Our results broadly confirm frontal and parietal functional variations in women with PTSD and suggest a compensatory nature of these variations with regard to the retreival of traumatic memories and global attentional deficits, respectively, during cognitively challenging tasks.     

Cognitive processing therapy for posttraumatic stress disorder in a residential treatment setting

Cognitive processing therapy (CPT) is an exposure-based protocol designed to reduce posttraumatic stress disorder (PTSD) symptoms and challenge faulty beliefs and interpretations that prevent trauma survivors from coming to terms with their traumatic experiences. This article provides a brief summary of this treatment and the related literature and describes how the CPT protocol was modified to implement this treatment in this study's setting. Also provided is a discussion of various institutional and intrapatient barriers that existed before the introduction of CPT and how these difficulties were ultimately resolved. Patients' responses to treatment, as indicated by both qualitative and quantitative data, are also reviewed. A total of 18 patients participated and completed treatment with CPT (50% Caucasian, 22.2% African American, 16.7% biracial, 5.6% Native American, and 5.6% Hispanic). Overall, the women participating in the protocol benefited greatly, and 15 of the 18 women had a statistically significant reduction in scores measuring PTSD symptoms. The article concludes with recommendations to other programs and providers interested in providing CPT to similar treatment populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved).     

Antiepileptic drugs in posttraumatic stress disorder

Antiepileptic drugs might be effective in the treatment of patients with Posttraumatic Stress Disorder, a condition with unmet pharmacologic needs. We review the literature on the efficacy and tolerability of antiepileptic drugs in Posttraumatic Stress Disorder, both case reports and open studies, as well as controlled studies if available. The results of the studies will be presented together with their methodological limitations (e.g., open trials, use of additional medications, and lack of use of standardized scales for Posttraumatic Stress Disorder). The effects of antiepileptic drugs on kindling, a suggested pathogenesis for Posttraumatic Stress Disorder are overviewed, and suggestions for further research are raised.     

Memory mechanisms in posttraumatic stress disorder

The authors present a new theory of the neurobiological mechanisms mediating the memory processes involved in posttraumatic stress disorder (PTSD). The current fear-conditioning model accounts for learning that underlies certain central features of PTSD, but it fails to account for peritraumatic memory disturbances, episodic memory phenomena that also are characteristic of the disorder. A more comprehensive model of PTSD, consistent with the clinical phenomenology of the disorder, is proposed on the basis of observations from human memory experiments. It is argued that the amygdala is the locus of consolidation of the core of the traumatic experience and that amygdalar inhibition of hippocampal function at high levels of emotional arousal mediates diminution of conscious memory for peritraumatic events. The model is amenable to specific experimental manipulations that should yield information pertinent to further development of theory and, ultimately, to more rational clinical intervention.     

Gene-environment interaction in posttraumatic stress disorder

The purpose of this article is to encourage research investigating the role of measured gene-environment interaction (G × E) in the etiology of posttraumatic stress disorder (PTSD). PTSD is uniquely suited to the study of G × E as the diagnosis requires exposure to a potentially-traumatic life event. PTSD is also moderately heritable; however, the role of genetic factors in PTSD etiology has been largely neglected both by trauma researchers and psychiatric geneticists. First, we summarize evidence for genetic influences on PTSD from family, twin, and molecular genetic studies. Second, we discuss the key challenges in G × E studies of PTSD and offer practical strategies for addressing these challenges and for discovering replicable G × E for PTSD. Finally, we propose some promising new directions for PTSD G × E research. We suggest that G × E research in PTSD is essential to understanding vulnerability and resilience following exposure to a traumatic event. Dr. Koenen is supported in part by US-NIMH K08 MH070627. Ananda Amstadter is supported by US-NIAAA T32 AA007474. Nicole Nugent is supported by US-NIMH T32 MH18869.