Combining clinical studies and analogue experiments to investigate cognitive mechanisms in posttraumatic stress disorder

Decontextualized fear memories? Stronger conditioned fear responses during extinction learning and extinction recall in a safe context predict the development of long-term analog intrusions

BACKGROUND

Difficulties in the context-dependent modulation of conditioned fear are known for posttraumatic stress disorder and may explain the occurrence of intrusive memories in safe contexts. The current study therefore investigated if reduced context-dependent modulation of conditioned fear and its underlying neural circuitry constitute risk factors for the development of analog intrusions in response to an experimental trauma.

METHODS

Eighty-five healthy women participated in the trauma film paradigm to investigate the development of analog intrusions as well as explicit memory for an experimental trauma after one week and three months, respectively. Before, participants underwent a context-dependent fear conditioning paradigm during functional magnetic resonance imaging with fear acquisition in context A and extinction training in context B on a first day, as well as extinction recall in context B and fear renewal in a novel context C one day later. Skin conductance responses (SCRs) and blood oxygen level dependent responses were main outcome measures.

RESULTS

In addition to stronger fear acquisition in context A, stronger conditioned fear responses in the safe context B, as indicated by stronger conditioned SCRs or stronger activation of fear expressing regions during extinction learning and recall, predicted the development of long-term analog intrusions.

CONCLUSIONS

Stronger fear responses in safe and danger contexts were risk factors for the development of long-term analog intrusions and point to decontextualized fear memories and difficulties in the context-dependent modulation of conditioned fear. Altered fear conditioning processes and reduced storage of contextual information may cause the occurrence of fear independent of context.

Is rumination associated with psychological distress after a cancer diagnosis? A systematic review

Objective: The aim of this work was to review evidence on the association between psychological rumination and distress in those diagnosed with cancer. Methods: Six databases were searched for studies exploring rumination alongside overall assessments of psychological distress, depression, anxiety, or stress. Results: Sixteen studies were identified. Rumination was associated with distress cross-sectionally and longitudinally. However, once baseline depression was controlled for, the association was no longer seen. The emotional valence of ruminative thoughts and the style in which they were processed, rather than their topic, was associated with distress. Brooding and intrusive rumination were associated with increased distress, deliberate rumination had no association, and reflection/instrumentality had mixed findings. Conclusions: This review highlights that it is not necessarily the topic of content, but the style and valence of rumination that is important when considering its association with distress. The style of rumination should be the target of clinical intervention, including brooding and intrusion.

How Expectations Shape the Formation of Intrusive Memories: An Experimental Study Using the Trauma Film Paradigm

Background

Although intrusions are the hallmark symptom of posttraumatic stress disorder, there is still limited knowledge about the processes that contribute to the development of intrusions. Here, we used the well-established trauma film paradigm (TFP) to investigate how expectations about the intensity and controllability of intrusions influence their occurrence.

Methods

90 healthy participants underwent the TFP before they were randomized to one of three conditions manipulating their expectations about intrusions: positive expectations group; negative expectations group; control group. The primary outcome was the frequency and severity of intrusive memories as assessed with an intrusion diary over seven days.

Results

The TFP was well implemented, as indicated by significant post-film anxiety and a substantial number of intrusions reported for the subsequent week. The three groups did not differ in their expectations about intrusions and, relatedly, in their experience of intrusions. A mediation analysis revealed that the influence of post-film anxiety on intrusive memories was fully mediated by expectations.

Conclusions

Despite the failure of the expectation manipulation, the results of the mediation analysis support the hypothesis that post-film expectations influence the formation of intrusive memories, suggesting that intrusions may result from maladaptive dynamics between emotional and cognitive processes following trauma(like) experiences.

Dysfunctional cognition in individuals with an increased risk for mania

Background

There is still a lack of knowledge about attitudes and cognitions that are related to bipolar disorder. Theoretically, it was proposed that exaggerated beliefs about the self, relationships, the need for excitement, and goal-related activities might lead to mania in vulnerable individuals, however, the few studies that examined this hypothesis provided mixed results. One of the unresolved issues is if such a cognitive style is associated with current mood symptoms or with different stages of the illness, i.e. at-risk versus diagnosed bipolar disorder. Therefore, the present study aimed at evaluating depression and mania-related cognitive style in individuals at-risk for mania.

Method

In an online survey, we collected data of 255 students of the University of Klagenfurt, Austria. All participants completed the Hypomanic Personality Scale (HPS), the Cognition Checklist for Mania – Revised (CCL-M-R), the Dysfunctional Attitude Scale (DAS), the Beck Depression Inventory (BDI), and the Internal State Scale (ISS).

Results

In a hierarchical regression, HPS was positively related to scores of all subscales of the CCL-M-R. The HPS did not significantly predict scores of the DAS. Current manic and depressive symptoms significantly contributed to the models.

Conclusion

The present results suggest that a trait-like risk for mania is associated with mania-related but not depression-related cognitions.

Individuals at-risk for mania show mania-specific rather than depression-specific thinking patters.

Current subclinical mood symptoms are related to mood-congruent attitudes and cognitions.

Recurrent involuntary autobiographical memories: characteristics and links to mental health status

Memories of events from one's personal past that come to mind unintentionally and effortlessly are termed involuntary autobiographical memories (IAMs). Recurrent IAMs are known as relevant to many disorders within clinical literature. However, less is known about their links with mental health status in the general population. In the current study, 2184 undergraduate students completed surveys assessing occurrence of any recurrent IAMs. Participants also wrote a description of their most frequently recurring IAM and rated it on phenomenological characteristics, such as frequency, valence, vividness, and centrality. Results showed that the majority of our sample experienced recurrent IAMs, replicating previous findings, but most of these memories were emotionally negative, unlike past work. Importantly, negative recurrent IAMs were associated with significantly more mental health concerns, including symptoms of depression, anxiety, and posttraumatic stress. We also found that frequency of IAM recurrence was predicted by the memory's age, level of completeness/detail, emotional intensity, and centrality to one's life story. Further, descriptions of positive recurrent IAMs contained significantly more episodic detail compared to negative or neutral ones, suggesting that emotional regulation may play a role in how recurrent IAMs are recounted. Recurrent IAMs, and their characteristics, serve as a window into mental health status.

Gazing at facial features increases dissociation and decreases attractiveness ratings in non-clinical females - A potential explanation for a common ritual in body dysmorphic disorder

Rituals, such as gazing at faces, are common in body dysmorphic disorder (BDD) and appear in cognitive-behavioral models as a maintaining factor. Rituals are also common in obsessive-compulsive disorder (OCD). In contrast to OCD, the proposed associations between rituals and intrusive thoughts/appearance preoccupation have not been empirically investigated for BDD. We examined if the assumed effect of gazing rituals on attractiveness ratings exists and if it is associated with dissociation. In an experiment, we asked N = 65 non-clinical females to focus on the nose of a photographed face at pre- and post-test. In between, participants gazed at the nose of either the same (relevant gazing) or another face (irrelevant gazing). We found increasing dissociation after gazing in both conditions and a differentially stronger decrease of attractiveness ratings in the relevant gazing condition. Our findings support the hypothesized effect of gazing rituals on attractiveness evaluation in cognitive-behavioral models for BDD.

Differential effects of sleep on explicit and implicit memory for potential trauma reminders: findings from an analogue study

Background: Recent findings suggest that disruptions of sleep-related memory processing are involved in the development of posttraumatic stress symptoms. More specifically, exposure to an analogue traumatic event resulted in fewer intrusive memories, when it was followed by sleep instead of continued wakefulness. However, competing evidence suggests that sleep deprivation may reduce intrusive re-experiencing. To address these conflicting accounts, we examined how sleep - as opposed to partial sleep deprivation - modulates explicit and implicit trauma memory using an analogue procedure. Methods: Healthy participants (N = 41) were assigned to a Sleep or Partial sleep deprivation group. Prior to nocturnal sleep, both groups were exposed to "traumatic" picture stories. After sleep or partial sleep deprivation, participants were subjected to tests of explicit and implicit memory for potential trauma reminders. Thereafter, participants completed an intrusion triggering task that was embedded in a distractor task. Results: Analyses revealed higher explicit memory for potential trauma reminders after sleep as compared to partial sleep deprivation. No group differences were found for implicit memory. Participants responded with fewer intrusions after sleep than following partial sleep deprivation. Conclusions: The current findings support a protective role of sleep in trauma memory processing, which may be evident after the first night of sleep post-trauma. Although more research is needed, our results corroborate the importance of promoting restful sleep in trauma-exposed individuals.

Susceptibility to others' emotions moderates immediate self-reported and biological stress responses to witnessing trauma

BACKGROUND

The peri-traumatic stress response is a strong predictor of symptom development after trauma exposure. Regarding witnessing trauma, the stress response might depend on the susceptibility to others' emotions (emotional contagion, EC). This study investigated whether EC moderates the immediate stress response using a trauma film paradigm.

METHODS

Ninety-five healthy participants were randomly exposed to a trauma or a neutral film. Perceived stressfulness of the film and pre-to post-film changes in self-reported anxiety, heart rate and saliva cortisol levels were assessed. EC towards negative and positive emotions was measured using the emotional contagion scale and its emotion-specific subscales.

RESULTS

Overall, the trauma film was perceived as distressing and elicited an increase in self-reported anxiety, heart rate and saliva cortisol levels relative to the neutral film. EC towards negative emotions was positively related to the perceived stressfulness of the film, increased anxiety and increased heart rate. The association with saliva cortisol levels was also in the expected direction, but not statistically significant. These associations were not found for EC towards positive emotions.

DISCUSSION

EC towards negative emotions may be an important predictor of trauma exposure outcomes. Further research should clarify its specific contribution in witnessing and undergoing trauma.

An empirical review of potential mediators and mechanisms of prolonged exposure therapy

Prolonged exposure (PE) is an empirically-supported treatment for posttraumatic stress disorder (PTSD), but the precise mechanism(s) by which PE promotes symptom change are not well established. Understanding how PE works is critical to improving clinical outcomes, advancing dissemination efforts, and enhancing transdiagnostic models of psychopathology. However, mechanisms research conducted in clinical treatment settings is complex, and findings may be difficult to interpret without appropriate context. This is the first review of potential mechanisms of PE to provide such context, by rigorously evaluating empirical findings in line with essential criteria for effective research on mechanisms (or mediators). We begin by describing six putative mechanisms identified by emotional processing theory and contemporary models of fear extinction, before thoroughly reviewing empirical findings from clinical research on PE and similar PTSD treatments. We provide a detailed description of each study and mechanism test, as well as ratings of strength of evidence and quality of evaluation based on a novel rating scheme. We highlight variables with strong evidence (belief change and between-session habituation), intermediate evidence (inhibitory learning and emotional engagement), and minimal support (narrative organization and within-session habituation). After discussing limitations of the extant literature and this review, we summarize specific challenges for research on PE mechanisms and highlight directions for future study based on clinical and research implications.

Investigating biological traces of traumatic stress in changing societies: challenges and directions from the ESTSS Task Force on Neurobiology

Traumatic stress can have severe consequences for both mental and physical health. Furthermore, both psychological and biological traces of trauma increase as a function of accumulating traumatic experiences. Neurobiological research may aid in limiting the impact of traumatic stress, by leading to advances in preventive and treatment interventions. To promote the possibility for clinical implementation of novel research findings, this brief review describes timely conceptual and methodological challenges and directions in neurobiological trauma research on behalf of the Task Force "Neurobiology of Traumatic Stress" of the European Society for Traumatic Stress Studies (ESTSS). The most important conceptual challenges are the heterogeneity of disorders and existence of subtypes across diagnostic categories: differential latent profiles and trajectories regarding symptom expression and neural correlates are being unraveled; however, similar latent classes' approaches for treatment response and neurobiological data remain scarce thus far. The key to improving the efficacy of currently available preventive interventions and treatments for trauma-related disorders lies in a better understanding and characterization of individual differences in response to trauma and interventions. This could lead to personalized treatment strategies for trauma-related disorders, based on objective information indicating whether individuals are expected to benefit from them. The most important methodological challenge identified here is the need for large consortia and meta-analyses or, rather, mega-analyses on existent data as a first step. In addition, large multicenter studies, combining novel methods for repeated sampling with more advanced statistical modeling techniques, such as machine learning, should aim to translate identified disease mechanisms into molecular blood-based biomarker combinations to predict disorder vulnerability and treatment responses.

Biases in probabilistic category learning in relation to social anxiety

Instrumental learning paradigms are rarely employed to investigate the mechanisms underlying acquired fear responses in social anxiety. Here, we adapted a probabilistic category learning paradigm to assess information processing biases as a function of the degree of social anxiety traits in a sample of healthy individuals without a diagnosis of social phobia. Participants were presented with three pairs of neutral faces with differing probabilistic accuracy contingencies (A/B: 80/20, C/D: 70/30, E/F: 60/40). Upon making their choice, negative and positive feedback was conveyed using angry and happy faces, respectively. The highly socially anxious group showed a strong tendency to be more accurate at learning the probability contingency associated with the most ambiguous stimulus pair (E/F: 60/40). Moreover, when pairing the most positively reinforced stimulus or the most negatively reinforced stimulus with all the other stimuli in a test phase, the highly socially anxious group avoided the most negatively reinforced stimulus significantly more than the control group. The results are discussed with reference to avoidance learning and hypersensitivity to negative socially evaluative information associated with social anxiety.

The origins of repetitive thought in rumination: separating cognitive style from deficits in inhibitory control over memory

BACKGROUND AND OBJECTIVES

Rumination is a major contributor to the maintenance of affective disorders and has been linked to memory control deficits. However, ruminators often report intentionally engaging in repetitive thought due to its perceived benefits. Deliberate re-processing may lead to the appearance of a memory control deficit that is better explained as a difference in cognitive style.

METHODS

Ninety-six undergraduate students volunteered to take part in a direct-suppression variant of the Think/No-Think paradigm after which they completed self-report measures of rumination and the degree to which they deliberately re-processed the to-be-suppressed items.

RESULTS

We demonstrate a relation between rumination and impaired suppression-induced forgetting. This relation is robust even when controlling for deliberate re-processing of the to-be-suppressed items, a behavior itself related to both rumination and suppression. Therefore, whereas conscious fixation on to-be-suppressed items reduced memory suppression, it did not fully account for the relation between rumination and memory suppression.

LIMITATIONS

The current experiment employed a retrospective measure of deliberate re-processing in the context of an unscreened university sample; future research might therefore generalize our findings using an online measure of deliberate re-processing or within a clinical population.

CONCLUSIONS

We provide evidence that deliberate re-processing accounts for some--but not all--of the relation between rumination and suppression-induced forgetting. The present findings, observed in a paradigm known to engage top-down inhibitory modulation of mnemonic processing, provide the most theoretically focused evidence to date for the existence of a memory control deficit in rumination.

An Integrated Model of Posttraumatic Stress and Growth

A number of recent models have examined cognitive predictors of posttraumatic stress and posttraumatic growth (S. Barton, A. Boals, & L. Knowles, 2013; J. Groleau, L. Calhoun, A. Cann, & G. Tedeschi, 2013; K. N. Triplett, R. G. Tedeschi, A. Cann, L. G. Calhoun, & C. L. Reeve, 2012). The current study examined an integrated model of predictors of distress and perceived growth in 194 college undergraduates. Domains covered included the roles of core belief challenge, event centrality, posttrauma cognitions, and event-related rumination. Negative cognitions about the self and the centrality of the event directly predicted both growth and distress, although intrusive rumination predicted only posttraumatic stress disorder symptoms, and deliberate rumination predicted only posttraumatic growth. Future research should continue to examine the shared and unique predictors of postevent growth and distress.

Flashbacks, intrusions, mind-wandering - Instances of an involuntary memory spectrum: A commentary on Takarangi, Strange, and Lindsay (2014)

In their paper, Takarangi, Strange, and Lindsay (2014) showed in two experiments that participants who had witnessed a shocking film frequently "mind-wandered without awareness" about the content of the film. More importantly, they equated this effect with the occurrence of traumatic intrusions. In this commentary, we argue that the authors adhered to conceptually ambiguous terms, and thereby unintentionally contribute to an already existing conceptual blur in the trauma-memory field. We postulate that clear definitions are urgently needed for phenomena such as intrusions, flashbacks, and mind-wandering, when using them in the context of trauma memory. Furthermore, our proposal is that these phenomena can fall under a spectrum of different involuntary memory instances. We propose that by adopting stricter definitions and viewing them as separate, but interrelated phenomena, different lines of trauma-memory research can be reconciled, which would considerably advance the field.

Can concreteness training buffer against the negative effects of rumination on PTSD? An experimental analogue study

BACKGROUND AND OBJECTIVES

Trauma-related rumination has been found to be an important maintaining factor for PTSD. On the background of the processing mode account of ruminative thinking, this study tested whether the relationship between rumination and analogue PTSD symptoms can be modified by training participants in a concrete mode of processing.

METHODS

Healthy participants were trained in either an abstract or a concrete style of processing. Afterwards, they watched a stressful film. The interactive effect of training condition and trait rumination on intrusive memories of the film was examined.

RESULTS

Following abstract training, a positive relationship between trait rumination and intrusive memories of the film emerged. As hypothesized, this relationship disappeared following concrete training.

LIMITATIONS

include the lack of a no-training control group and the analogue paradigm used.

CONCLUSIONS

The study provides preliminary evidence that the relationship between trait rumination and analogue PTSD symptoms can be modified. If replicated in future studies, it may be promising to examine the value of concreteness training for prevention and/or treatment of PTSD.

Perceptual processing during trauma, priming and the development of intrusive memories

BACKGROUND

Intrusive reexperiencing in posttraumatic stress disorder (PTSD) is commonly triggered by stimuli with perceptual similarity to those present during the trauma. Information processing theories suggest that perceptual processing during the trauma and enhanced perceptual priming contribute to the easy triggering of intrusive memories by these cues.

METHODS

Healthy volunteers (N = 51) watched neutral and trauma picture stories on a computer screen. Neutral objects that were unrelated to the content of the stories briefly appeared in the interval between the pictures. Dissociation and data-driven processing (as indicators of perceptual processing) and state anxiety during the stories were assessed with self-report questionnaires. After filler tasks, participants completed a blurred object identification task to assess priming and a recognition memory task. Intrusive memories were assessed with telephone interviews 2 weeks and 3 months later.

RESULTS

Neutral objects were more strongly primed if they occurred in the context of trauma stories than if they occurred during neutral stories, although the effect size was only moderate [Formula: see text] and only significant when trauma stories were presented first. Regardless of story order, enhanced perceptual priming predicted intrusive memories at 2-week follow-up (N = 51), but not at 3 months (n = 40). Data-driven processing, dissociation and anxiety increases during the trauma stories also predicted intrusive memories. Enhanced perceptual priming and data-driven processing were associated with lower verbal intelligence.

LIMITATIONS

It is unclear to what extent these findings generalize to real-life traumatic events and whether they are specific to negative emotional events.

CONCLUSIONS

The results provide some support for the role of perceptual processing and perceptual priming in reexperiencing symptoms.

Vividness of general mental imagery is associated with the occurrence of intrusive memories

BACKGROUND AND OBJECTIVES

Intrusive memories of traumatic events constitute a core feature of post-traumatic stress disorder. However, the association of pre-traumatic factors with post-traumatic intrusive memories is still only poorly understood. The current study investigated the extent to which vividness of general mental imagery prior to an analogue stressor is positively associated with occurrence of intrusive images following such a stressor.

METHODS

Sixty-seven participants were exposed to video material depicting the aftermath of serious road traffic accidents. Additionally, participants filled in questionnaires on mental imagery, affect, peri-traumatic processing style, and intrusive memories.

RESULTS

Vividness of mental imagery before the analogue stressor correlated positively with the amount, vividness, and emotional distress due to intrusive images shortly after the analogue stressor and on the subsequently five days. Importantly, mental imagery assessed pre-stressor was associated with intrusive memories independently of trait anxiety and depression as well as participants' emotional response to the video. Peri-traumatic data-driven processing was also related to intrusive memories but not to the vividness of pre-stressor mental imagery.

LIMITATIONS

An analogue design was used. Results need to be replicated in a prospective design with survivors of traumatic events according to DSM-IV criteria.

CONCLUSIONS

The findings indicate that high levels of vividness of general mental imagery may contribute to the development of intrusive imaginal memories following exposure to traumatic events.