The effect of arousal on memory for emotionally-relevant information: a study of skydivers

The aim of the present study was to test memory for information under conditions of extreme arousal in an analogue design to mimic hyperarousal during trauma exposure. Prior to their skydive, 70 novice skydivers were administered measures of fear, heart rate, and anxiety sensitivity. Half the participants learnt a list of words that varied in both relevance to their skydive and valence (irrelevant/relevant, negative/neutral) on the plane (skydivers), and remaining participants learnt an identical list of words on the ground (delayed controls). Following the skydive, participants completed free recall and recognition tasks; heart rate, dissociation, and subjective arousal were also measured. Consistent with an attentional narrowing hypothesis, skydivers recalled comparable a comparable number of relevant words as delayed controls, but significantly less irrelevant words. In terms of recognition performance, skydivers displayed better recognition of relevant words but poorer recognition of irrelevant words than delayed controls. Valence of words did not alter the pattern of results. The implications of the findings are discussed in the context of understanding memory processes under conditions of high threat.     

How time flies: a study of novice skydivers

Although time distortion is commonly reported during a traumatic experience, there is little research addressing the phenomenon. This study investigated the role of affect in time perception in a very stressful experience by indexing novice tandem skydivers' (N=76) levels of fear and excitement before the skydive and soon after landing. Estimations of how long skydivers thought their experience lasted were obtained after landing. Whereas increased fear was associated with the perception of time passing slowly, increased excitement was associated with the perception of time passing quickly. These data support models of time perception based on avoidance and approach motivations influencing time distortion.     

Peritraumatic dissociation mediates the relationship between acute panic and chronic posttraumatic stress disorder

Although peritraumatic dissociation predicts subsequent posttraumatic stress disorder (PTSD), little is understood about the mechanism of this relationship. This study examines the role of panic during trauma in the relationship between peritraumatic dissociation and subsequent PTSD. Randomized eligible admissions to 4 major trauma hospitals across Australia (n = 244) were assessed during hospital admission and within one month of trauma exposure for panic, peritraumatic dissociation and PTSD symptoms, and subsequently re-assessed for PTSD three months after the initial assessment (n = 208). Twenty (9.6%) patients met criteria for PTSD at 3-months post injury. Structural equation modeling supported the proposition that peritraumatic derealization (a subset of dissociation) mediated the effect of panic reactions during trauma and subsequent PTSD symptoms. The mediation model indicated that panic reactions are linked to severity of subsequent PTSD via derealization, indicating a significant indirect relationship. Whereas peritraumatic derealization is associated with chronic PTSD symptoms, this relationship is influenced by initial acute panic responses.     

Self-reports of trauma and dissociation: An examination of context effects

To examine context effects in moderating the link between self-reported trauma and dissociation in undergraduate samples, we administered these measures either in the same or different experimental contexts. Trauma History Screen/THS (Carlson et al., 2011)-Dissociative Experiences Scale/DES-II (Bernstein & Putnam, 1986) correlations revealed a context effect (greater correlations in same test context), although multiple regression analyses did not confirm this finding. A context effect was supported in DES-Taxon scores using multiple regression for the THS but not the Modified Posttraumatic Stress Scale (MPSS-SR; Falsetti, Resnick, Resick, & Kilpatrick, 1993), an effect confirmed with correlation comparisons. Ethnicity influenced the association between measures of trauma and dissociation. Overall, the relation between measures of trauma and dissociation was small to medium, although high correlations were observed between the DES depersonalization/derealization subscale and the Multiscale Dissociation Inventory (Briere, Weathers, & Runtz, 2005) depersonalization and derealization subscales, supporting the construct validity of these measures.     

Experimentally-induced dissociation impairs visual memory

Dissociation is a phenomenon common in a number of psychological disorders and has been frequently suggested to impair memory for traumatic events. In this study we explored the effects of dissociation on visual memory. A dissociative state was induced experimentally using a mirror-gazing task and its short-term effects on memory performance were investigated. Sixty healthy individuals took part in the experiment. Induced dissociation impaired visual memory performance relative to a control condition; however, the degree of dissociation was not associated with lower memory scores in the experimental group. The results have theoretical and practical implications for individuals who experience frequent dissociative states such as patients with posttraumatic stress disorder (PTSD).     

Peritraumatic dissociation and experiential avoidance as predictors of posttraumatic stress symptomatology

This study examined whether peritraumatic dissociation serves as a proxy risk factor for experiential avoidance in its relationship with posttraumatic stress disorder (PTSD) symptomatology. One hundred eighty-five trauma survivors completed measures that assessed for peritraumatic dissociation, experiential avoidance, and PTSD symptom severity. The results indicated that peritraumatic dissociation and experiential avoidance were significantly related to PTSD symptomatology at baseline. However, after initial levels of PTSD symptomatology were taken into account, only experiential avoidance was related to PTSD symptoms both 4- and 8-weeks later. These results indicate that peritraumatic dissociation is not a proxy risk factor for experiential avoidance and contributes to the growing body of literature indicating that experiential avoidance is an important factor related to the psychological symptoms experienced by trauma survivors.     

Peritraumatic dissociation and posttraumatic stress after pregnancy loss: a prospective study

This study examined (1). predictors for peritraumatic dissociation, (2). its relations with acute and chronic symptoms of posttraumatic stress disorder (PTSD), and (3). pathways regarding these relations in response to pregnancy loss. In early pregnancy, about 1370 women volunteers completed questionnaires for neuroticism, control over emotions, dissociative tendencies, absorption, and prior life events. Of these, 126 subsequently experienced pregnancy loss and most of them completed measures 1 month (N = 118) and 4 months (N = 104) later. At 1 month, peritraumatic dissociation, memory of pregnancy loss (degree of fragmentation, sensory impressions, and emotional intensity), thought suppression, and PTSD symptoms were assessed, and at 4 months, PTSD symptoms were re-assessed. Peritraumatic dissociation was predicted by prior low control over emotions, dissociative tendencies, and lower education. It was not predicted by neuroticism, absorption, and prior life events. Peritraumatic dissociation was related to acute PTSD symptoms and LISREL analyses indicated that self-reported memory fragmentation and thought suppression of pregnancy loss mediated this relation. It also predicted chronic PTSD symptoms, and this relation was mediated by acute PTSD symptoms.     

Fear response to dissociation challenge

Abstract

Participants (N = 101) scoring high or low on a new scale for assessing fear of dissociative sensations (Dissociation Sensitivity Index) underwent an audio/visual sensory challenge using a device called the D.A.V.I.D. Participants' report of subjective fear and level of dissociation were measured before and after completing the audio/visual sensory challenge. Consistent with prediction, participants scoring high on the DSI responded to the challenge with significantly greater increases in subjective fear and dissociative symptoms relative to those scoring low on the DSI. Contrary to prediction, the DSI performed poorer than the Anxiety Sensitivity Index in predicting participants' response to the audio/visual sensory challenge. Theoretical and clinical implications of the findings are discussed.     

Memory and suggestibility in maltreated children: age,stress arousal,dissociation, and psychopathology

The present study was designed to assess children's memory and suggestibility in the context of ongoing child maltreatment investigations. One hundred eighty-nine 3-17-year-olds involved in evaluations of alleged maltreatment were interviewed with specific and misleading questions about an anogenital examination and clinical assessment. For the anogenital examination, children's stress arousal was indexed both behaviorally and physiologically. For all children, individual-difference data were gathered on intellectual and short-term memory abilities, general psychopathology, and dissociative tendencies. Interviewers' ratings were available for a subset of children concerning the amount of detail provided in abuse disclosures. Results indicated that general psychopathology, short-term memory, and intellectual ability predicted facets of children's memory performance. Older compared to younger children evinced fewer memory errors and greater suggestibility resistance. Age was also significantly related to the amount of detail in children's abuse disclosures. Neither dissociation nor stress arousal significantly predicted children's memory. Implications for understanding maltreated children's eyewitness memory are discussed.     

Schizophrenia, dissociation, and consciousness

Current thinking suggests that dissociation could be a significant comorbid diagnosis in a proportion of schizophrenic patients with a history of trauma. This potentially may explain the term “schizophrenia” in its original definition by Bleuler, as influenced by his clinical experience and personal view. Additionally, recent findings suggest a partial overlap between dissociative symptoms and the positive symptoms of schizophrenia, which could be explained by inhibitory deficits. In this context, the process of dissociation could serve as an important conceptual framework for understanding schizophrenia, which is supported by current neuroimaging studies and research of corollary discharges. These data indicate that the original conception of “split mind” may be relevant in an updated context. Finally, recent data suggest that the phenomenal aspects of dissociation and conscious disintegration could be related to underlying disruptions of connectivity patterns and neural integration.     

The influence of a visuospatial grounding task on intrusive images of a traumatic film

Nonclinical participants watched a trauma film under two processing conditions. During part of the film participants carried out a concurrent visuospatial grounding task consisting of the construction of shapes out of plasticine (modelling clay), while the rest of the film constituted a control, no task condition. The visuospatial task was predicted to selectively compete for processing resources required for intrusive image formation. As predicted, spontaneous intrusive images during the succeeding week were significantly less common from those parts of the film that coincided with the concurrent task. The task had no effect on levels of distress or peritraumatic dissociation, consistent with the hypothesis that intrusions were reduced because the task competed for resources necessary for encoding into an image-based memory system.     

Sleep experiences,dissociation, imaginal experiences,and schizotypy: The role of context

Watson (2001) reported moderate correlations between the Iowa Sleep Experience Survey (ISES) and self-report measures of dissociation and schizotypy. Subsequent investigations (Fassler, Knox, & Lynn, 2003; Watson, 2003) reported similar, although somewhat more modest, correlations between the ISES and measures of dissociation and schizotypy, as well as with measures of absorption and negative affect. The present study tested subjects in conditions in which the measures of sleep experiences were administered with other measures in either the same (N = 86) or a different (N = 87) test context. We determined that sleep experiences were associated with measures of dissociation, absorption, and schizotypy. We closely replicated Watson (2001) and found that the ISES correlations with other measures were not affected by the test context. We suggest that Watson’s (2001) hypothesized common domain of unusual cognitive and perceptual experiences (e.g., sleep experiences) may be underpinned by common ties to imaginative experiences.     

Cross cultural evaluation of smokers risk for panic and anxiety pathology: a test in a Russian epidemiological sample

The present study evaluated the main and interactive effects of level of smoking (cigarettes per day) and anxiety sensitivity (fear of anxiety and anxiety related sensations) in predicting panic and anxiety variables in an epidemiologically-defined sample of smokers from Moscow (n=95). The combination of high levels of anxiety sensitivity and smoking predicted agoraphobic avoidance, but not frequency of panic attacks during the past week. These findings suggest anxiety sensitivity may moderate the relation between level of smoking and prototypical panic psychopathology variables (panic attacks and agoraphobic avoidance) even after controlling for the theoretically-relevant factors of alcohol abuse and negative affect.     

Unique contributions of anxiety sensitivity to avoidance: a prospective study in adolescents

Examination of the prospective relation between anxiety sensitivity (AS) and behavioral avoidance is largely absent from the literature. In a longitudinal study of a community sample of 2246 adolescents, participants completed the Anxiety Sensitivity Index (ASI; Reiss, Peterson, Gursky, & McNally (1986). Behaviour Research & Therapy, 24, 1-8), State-Trait Anxiety Inventory (STAI; Spielberger (1983). STAI: Manual for the Stait-Trait Anxiety Inventory. Palo Alto: Consulting Psychologists Press), and the Fear Questionnaire (Marks & Matthews (1979). Behaviour Research & Therapy, 17, 263-267) on an annual basis. To stringently test AS's ability to prospectively predict behavioral avoidance, linear regression was used to test whether AS factors predicted variance in follow-up behavioral avoidance scores after controlling for gender, trait anxiety, panic attacks, and baseline avoidance. Results indicted that the mental and physical subscales of the ASI predicted change in behavioral avoidance. The findings of the study are consistent with the view that AS may serve as a precursor to avoidant behavior and that, regardless of whether or not acute panic has been experienced, those who fear autonomic arousal may be more likely to avoid situations in which those sensations may be present.     

A cross-modal weapon focus effect: The influence of a weapon's presence on memory for auditory information

To examine whether a weapon's presence impairs witnesses' memory for auditory information (as it impairs memory for visual information), we conducted two experiments in which undergraduates watched one version of a videotape depicting a male target who held either a weapon or a neutral object and conversed with a female character. The semantic content of his remarks was either easy or difficult to comprehend. The weapon's presence did not affect voice identification accuracy or memory for the target's vocal characteristics (e.g., pitch, loudness, speech rate) but did worsen memory for semantic content in the Difficult Comprehension condition. Our results can be explained by multiple resource models of attention, which propose separate resource “pools” for different sensory modalities.     

Enhanced perceptual priming for neutral stimuli occurring in a traumatic context: two experimental investigations

Intrusive memories in posttraumatic stress disorder are often triggered by stimuli that are perceptually similar to those present shortly before or during the trauma. The present study aims to examine the possible role of perceptual priming in this phenomenon. It further investigates whether the degree of perceptual priming is associated with dissociation and whether both perceptual priming and intrusive memories can be reduced through elaboration. Two experiments measured perceptual priming for neutral stimuli that immediately preceded a "traumatic" event. Volunteers (N=46, 92) watched a series of "traumatic" and neutral picture stories, and completed a blurred object identification (perceptual priming) memory task, and a recognition memory task. Participants in Experiment 1 were selected to score either high or low on the Trait Dissociation Questionnaire [Murray, Ehlers, & Mayou (2002). Dissociation and posttraumatic stress disorder: Two prospective studies of motor vehicle accident survivors. British Journal of Psychiatry, 180, 363-368]. They also completed a state dissociation measure in the session. Experiment 2 randomly allocated participants to an experimental condition designed to increase elaboration or to a control condition. This experiment also included a measure of intrusive memories. Both experiments found enhanced perceptual priming for the stimuli that immediately preceded the "traumatic" stories compared to those preceding neutral stories. Participants with high trait dissociation showed relatively stronger perceptual perceptual priming. The degree of perceptual priming for stimuli from the "traumatic" stories also correlated with state dissociation (Experiment 1). Experimental manipulation of the elaboration of the stories showed that elaboration reduced the enhanced perceptual priming effect and the relative probability of reexperiencing symptoms (Experiment 2). The results support the role of perceptual priming in intrusions after traumatic events.     

Self-concept integration and differentiation in subclinical individuals with dissociation proneness

Dissociative pathology is characterized by an altered sense of self. Still, it remains unclear (a) whether the altered sense of self is also associated with non-pathological dissociation as well and (b) whether this potential association is an intrinsic connection or a consequence of other related constructs, including childhood trauma. This study addresses this question by examining how self-concept organization may differ among individuals with different levels of dissociation proneness. The structure of self-concept was operationalized by various indexes of self-concept integration and differentiation. Results showed that individuals high in dissociation proneness have lower self-concept clarity and compartmentalize self-aspects with more polarized evaluations. Notably, the association between dissociation proneness and evaluative self-compartmentalization held after controlling for childhood trauma, anxiety, and depression. This characteristic self-concept organization can be an attribute of non-pathological dissociation.     

Respiratory symptoms and panic in the National Comorbidity Survey: a test of Klein's suffocation false alarm theory

According to suffocation false alarm theory (Arch. Gen. Psychiatry 50 (1993) 31), respiratory symptoms are the symptoms that best distinguish the panic attacks of individuals with panic disorder (PD) from those of individuals without PD. Using National Comorbidity Survey data from those 609 respondents who had lifetime histories of panic attacks or PD, we tested this prediction. Neither respiratory symptom (smothering; dyspnea) strongly differentiated between respondents with PD and those with only panic attacks. Respiratory symptom endorsement was unrelated to PD when the number of other symptoms endorsed was controlled; furthermore, respiratory symptoms had slight effect sizes and were not included in a multivariate context. In contrast, fear of dying had the largest effect size, an association with PD that persisted after control for other symptom endorsement, and a continuing importance in multivariate analyses. Strikingly, panic attack respondents who reported having had only one panic attack were as likely as PD respondents to report respiratory symptoms during panic. These findings, although based on retrospective self-report and thus subject to recall bias, are inconsistent with the hypothesis that respiratory symptoms during panic have diagnostic significance.     

Full statistical mediation of the relationship between trauma and depressive symptoms

Owing to the potentially devastating effects of trauma‐induced depression, explaining the relationship between trauma and depressive symptoms is important. In this study, we measured lifelong exposure to potentially traumatic events and depressive symptoms in 370‐female undergraduates. We also measured anxiety, past negative time perspective and dissociation as potential mediators. Trauma exposure and depressive symptoms were related with a small but significant effect size (r = .16). Trauma was not associated with dissociation. We found that past negative time perspective and anxiety were full statistical mediators of this trauma‐depressive symptoms relationship. These two mediators combined accounted for all of the variance in that association. Anxiety accounted for more of the variance than past negative time perspective. A proposed explanation is that trauma both affectively elevates anxiety and cognitively creates an enduring focus on the events. Chronic anxiety and a past negative time perspective may lead to depression over time. The clinical implications are possible explanations as to why some treatments work.     

Smoking and Non-Clinical Panic Attacks: An Initial Empirical Test of Panic-Relevant Cognitive Processes

The present study evaluated panic-relevant cognitive processes in a sample of persons ( n = 70) who met criteria for either: (a) a positive panic attack history and regular smoking (smoking at least 10 cigarettes per day for S 12 months); (2) a positive panic attack history but no history of smoking; or (3) regular smoking history alone (smoking at least 10 cigarettes per day for S 12 months). As hypothesized, participants in group (a) demonstrated significantly greater bodily vigilance and anxiety sensitivity Mental Incapacitation Concerns compared with persons in either groups (b) or (c). Effects involving other dimensions of anxiety sensitivity, suffocation fear and trait anxiety did not discriminate between panickers as a function of smoking status. The observed effects could not be attributed to self-reported physical health status or history of medical problems. The implication of the present findings for understanding the potential role of smoking in panic pathology is discussed.