Self-report may underestimate trauma intrusions

Beneficial effects of mindfulness-based intervention on hippocampal volumes and episodic memory for childhood adversity survivors

Background

Adverse Childhood Experience (ACE) has detrimental impacts on neural development, especially hippocampal morphometry. Mindfulness-Based Interventions (MBI) has been shown to induce adaptive hippocampal changes especially at the subiculum. The present study aims to investigate the effects of MBI on subiculum volumes among ACE survivors, as well as the effects on episodic memory as a probe into hippocampal functionality.

Methods

We analyzed anatomical MRI data and performance indices from an episodic memory task called the Mnemonic Similarity Task (MST) collected from a randomized controlled longitudinal study that compared an 8-week MBI (N = 20) to an active control condition of Stress Management Education (SME) (N = 19). FreeSurfer 6.0 was used for automated hippocampal subfield segmentation and volumetric estimation.

Results

Significant group differences were observed with the volumetric changes of the right whole hippocampus and right subiculum. Only the MBI group showed improved pattern separation capability from MST, which was associated with stress reduction and right subiculum volumetric changes.

Limitations

Modest sample size. MST task was performed outside of MRI.

Conclusions

These findings suggest beneficial effects of MBI for hippocampal volumes and episodic memory, while highlighting the importance of the subiculum for MBI-induced neural and cognitive changes. The subiculum's known role in inhibitory control was interpreted as a potential mechanism for it to exhibit MBI-induced volumetric changes, which sheds light on the potential neural underpinnings of mindfulness meditation for reducing stress reactivity among ACE survivors.

Exploring intrusions without awareness: A preliminary study of the characteristics and influences of meta-awareness failures

BACKGROUND AND OBJECTIVES

Research shows that people can lack meta-awareness (i.e., being explicitly aware) of their trauma-related thoughts, which impacts our understanding of re-experiencing symptoms, a key symptom type in posttraumatic stress disorder (PTSD), assessed through self-report. This preliminarily study explored differences between (meta-)aware and unaware intrusion characteristics to understand why some intrusions are not immediately apparent to individuals.

METHODS

Trauma-exposed participants (N = 78) were recruited from online crowd-sourcing platforms to complete an online meta-awareness task. During a reading task, participants were intermittently probed to index the occurrence of unreported (i.e., unaware) trauma-related intrusions. Once participants indicated trauma-related intrusions were present, they then completed a questionnaire that indexed intrusion characteristics.

RESULTS

Although unaware intrusions did occur in a subset of the sample, there were no fundamental differences between aware and unaware intrusions in terms of modality of experience (imagery vs. non-imagery), meaningfulness, accessibility, or other characteristics (e.g., vividness).

LIMITATIONS

There was potential for lower participant engagement and attention due to the online delivery of the meta-awareness task, which may have minimized meta-awareness failure. Future research could consider using a continuous measure to index levels of meta-awareness. In addition, recruiting clinical samples (e.g., individuals with PTSD) who typically experience multiple daily intrusions would allow generalizability of the current findings to be tested.

CONCLUSIONS

Our findings from this preliminary study suggest that unaware and aware intrusions show more commonality than not in their characteristics, with further research required to improve our understanding of the mechanisms leading to meta-awareness or lack of in PTSD.

Detection of traumatic stress in the presence of traumatic experiences: the role of resilience factors in foster care children five years or younger

BACKGROUND

Children less than five years of age comprised approximately 30% in 2020 of foster care entries in the United States, and they are consistently the largest foster care entry group. Very young children can respond differently to the same adverse life events. Detection of complex interpersonal traumas is core to providing appropriate interventions and prevention of reoccurring negative outcomes in these children.

METHODS

Children who (1) were identified as having experienced complex interpersonal trauma, but (2) who did not have traumatic stress symptoms were identified using Child and Adolescent Needs and Strengths data in a large midwestern state from 2010 to 2021. A logistic model was fit to determine the effect of cumulative traumatic exposures (e.g., adverse childhood experiences such that increased events were hypothesized to predict an increased likelihood of symptomatic detection. We conducted a latent class analysis to understand the relationship between traumatic experiences, asset-based factors, and the detection of traumatic stress in children aged five years and under who had exposure to traumatic events but did not have detectable traumatic stress symptoms.

RESULTS

We detected three classes within this population of very young children, who were described as "resilient" (demonstrating asset-based resilience when faced with traumatic experiences), "missed" (those who exhibit behavioral and mental health types like those with detected traumatic stress symptoms but who were not detected as such), and "unfolding". Very young children do demonstrate asset-based resilience when faced with traumatic experiences.

CONCLUSIONS

Detection of traumatic stress may be more difficult in young children. It is important to assess both traumatic stress and strengths to ensure that children who are resilient after exposure to traumatic experiences (i.e., do not demonstrate traumatic stress symptoms) are not referred to unnecessary interventions. Additional educational approaches are needed to help caseworkers identify symptoms of traumatic stress that mirror symptoms of other behavioral and emotional challenges. Precision medicine approaches are required to best match the interventions to specific needs of young children. Recognition of resilience in very young children is critical for designing systems that customize approaches of trauma-informed care.

Investigating features that contribute to evaluations of intrusiveness for thoughts and memories

What makes a thought feel intrusive? One possibility is that traumatic experiences are the primary cause of intrusive thoughts and memories. Another possibility is that experiences of intrusiveness arise from the features involved with re-experiencing. We investigated several features that may lead a thought to feel intrusive: task-congruence, repetition, and affective content. In Experiment 1, participants listened to popular song clips expected to become stuck in one's head. In Experiment 2, participants were cued to recall their own autobiographical memories. We found that both songs and autobiographical memories replaying mentally felt more intrusive when they were incongruent with the current task, cued repeatedly, and had negative emotional content. Additionally, even liked songs and positive autobiographical memories were evaluated as highly intrusive under some conditions. Based on these findings, we argue that intrusiveness is not limited to traumatic thoughts, but rather is a context-dependent evaluation influenced by a variety of features.

Oxytocin vs. placebo effects on intrusive memory consolidation using a trauma film paradigm: a randomized, controlled experimental study in healthy women

Oxytocin administration during a trauma analogue has been shown to increase intrusive memories, which are a core symptom of post-traumatic stress disorder (PTSD). However, it is unknown whether oxytocin influences the acquisition or the consolidation of the trauma. The current study investigates the effect of the activation of the oxytocin system during the consolidation of an analogue trauma on the formation of intrusive memories over four consecutive days and whether this effect is influenced by individual neurobiological, genetic, or psychological factors. We conducted a randomized double-blind placebo-controlled study in 217 healthy women. They received either a single dose of intranasal oxytocin (24 IU) or placebo after exposure to a trauma film paradigm, which reliably induces intrusive memories. We used a general random forest to examine a potential heterogeneous treatment effect of oxytocin on the consolidation of intrusive memories. Furthermore, we used a poisson regression to examine whether salivary alpha amylase activity (sAA) as a marker of noradrenergic activity and cortisol response to the film, polygenic risk score (PRS) for psychiatric disorders, and psychological factors influence the number of intrusive memories. We found no significant effect of oxytocin on the formation of intrusive memories (F(2, 543.16) = 0.75, p = 0.51, ηp2 = 0.00) and identified no heterogeneous treatment effect. We replicated previous associations of the PRS for PTSD, sAA and the cortisol response on intrusive memories. We further found a positive association between high trait anxiety and intrusive memories, and a negative association between the emotion regulation strategy reappraisal and intrusive memories. Data of the present study suggest that the consolidation of intrusive memories in women is modulated by genetic, neurobiological and psychological factors, but is not influenced by oxytocin. Trial registration: NCT03875391.

The effects of computerised metacognitive cognitive bias modification training on the development of adaptive metacognitive beliefs and post-traumatic stress disorder symptoms

BACKGROUND AND OBJECTIVES

Maladaptive metacognitive beliefs are associated with the development of post-traumatic stress disorder (PTSD) symptoms following trauma, however it remains unclear whether training people to adopt healthy metacognitive beliefs helps to protect against the development of PTSD symptoms. We developed and tested a new cognitive bias modification training protocol (CBM_Metacog) that aimed to prevent analogue PTSD by training people to adopt healthy metacognitive beliefs prior to watching a distressing film.

METHODS

Participants (N = 135) received CBM_Metacog or a control CBM training and then watched a trauma film. We assessed participants' metacognitive appraisal style/beliefs, analogue PTSD symptoms, including intrusions and meta-awareness of their intrusions.

RESULTS

CBM_Metacog led participants to adopt healthier metacognitive beliefs relative to the control training. Importantly, CBM_Metacog participants reported fewer film intrusions over a 7-day period compared to the control group. CBM_Metacog did not increase participants' meta-awareness of their intrusions.

LIMITATIONS

As this was the first study to manipulate metacognitive beliefs related to an analogue trauma via CBM, we chose to use a healthy participant sample. Therefore, further research is needed before these results can be generalised to clinical samples.

CONCLUSIONS

Overall, these results suggest that training people to adopt healthy metacognitive beliefs, prior to trauma exposure, may help reduce vulnerability to PTSD.

Something Distressing This Way Comes: The Effects of Trigger Warnings on Avoidance Behaviors in an Analogue Trauma Task

Avoidance is one of the purported benefits and harms of trigger warnings-alerts that upcoming content may contain traumatic themes. Yet, previous research has focused primarily on emotional responses. Here, we used a trauma analogue design to assess people's avoidance behavior in response to stimuli directly related to an analogue trauma event. University undergraduates (n = 199) watched a traumatic film and then viewed film image stills preceded by either a trigger warning or a neutral task instruction. Participants had the option to "cover" and avoid each image. Apart from a minor increase in avoidance when a warning appeared in the first few trials, we found that participants did not overall avoid negative stimuli prefaced with a trigger warning any more than stimuli without a warning. In fact, participants were reluctant overall to avoid distressing images; only 12.56% (n = 25) of participants used the option to cover such images when given the opportunity to do so. Furthermore, we did not find any indication that trigger warning messages help people to pause and emotionally prepare themselves to view negative content. Our results contribute to the growing body of literature demonstrating that warnings seem trivially effective in achieving their purported goals.

Intranasal oxytocin administration impacts the acquisition and consolidation of trauma-associated memories: a double-blind randomized placebo-controlled experimental study in healthy women

Intrusive memories are a hallmark symptom of post-traumatic stress disorder (PTSD) and oxytocin has been implicated in the formation of intrusive memories. This study investigates how oxytocin influences the acquisition and consolidation of trauma-associated memories and whether these effects are influenced by individual neurobiological and genetic differences. In this randomized, double-blind, placebo-controlled study, 220 healthy women received either a single dose of intranasal 24IU oxytocin or a placebo before exposure to a trauma film paradigm that solicits intrusive memories. We used a "general random forest" machine learning approach to examine whether differences in the noradrenergic and hypothalamic-pituitary-adrenal axis activity, polygenic risk for psychiatric disorders, and genetic polymorphism of the oxytocin receptor influence the effect of oxytocin on the acquisition and consolidation of intrusive memories. Oxytocin induced significantly more intrusive memories than placebo did (t(188.33) = 2.12, p = 0.035, Cohen's d = 0.30, 95% CI 0.16-0.44). As hypothesized, we found that the effect of oxytocin on intrusive memories was influenced by biological covariates, such as salivary cortisol, heart rate variability, and PTSD polygenic risk scores. The five factors that were most relevant to the oxytocin effect on intrusive memories were included in a Poisson regression, which showed that, besides oxytocin administration, higher polygenic loadings for PTSD and major depressive disorder were directly associated with a higher number of reported intrusions after exposure to the trauma film stressor. These results suggest that intranasal oxytocin amplifies the acquisition and consolidation of intrusive memories and that this effect is modulated by neurobiological and genetic factors. Trial registration: NCT03031405.

Prosocial behaviour reduces unwanted intrusions of experimental traumatic memories

Following trauma exposure, people often experience involuntary intrusions of traumatic memories, i.e., flashbacks. How to reduce such unwanted intrusions attracts attention from basic and translational memory research, with a goal to safeguard mental well-being and promote resilience. Here, based on prosocial behaviour's well-documented psychological benefits, we hypothesized that post-trauma prosocial behaviour would causally reduce trauma-related symptoms, including involuntary intrusions. To test this novel hypothesis, we conducted two pre-registered lab studies (N = 180) using trauma films to induce lab-analogue trauma exposure. Following trauma exposure, participants were randomly assigned to prosocial or non-prosocial conditions. Specifically, in the prosocial condition, participants donated money to their preferred charities. In the non-prosocial conditions, participants completed either a neutral, number judgement task (Experiment 1) or a proself task (Experiment 2). Participants completed a 1-week intrusion diary and Impact of Event Scale-Revised (IES-R), to assess frequencies of traumatic intrusions and post-trauma stress disorder symptoms, respectively. Results showed that compared to non-prosocial behaviour, prosocial engagement (i.e. performing charitable donations) reduced involuntary traumatic intrusions in both lab settings and in their daily life as evidenced by 1-week intrusion diaries. While exploratory mediation analyses suggested that intrusion reduction was partly driven by enhanced positive affect afforded by prosocial behaviour, future studies are required to illuminate the underlying mechanisms. To the extent that post-trauma prosociality alleviated trauma-related symptoms, future research is warranted to investigate how various forms of prosocial behaviour in naturalistic setting could promote resilience following trauma exposure.

The cost of being absent: Is meta-awareness of mind-wandering related to depression symptom severity, rumination tendencies and trauma intrusions?

BACKGROUND

Deng, Li and Tang (2014) reported that depression symptom severity is negatively associated with dispositional mindfulness and importantly, positively associated with zone-outs (mind-wandering without meta-awareness). We replicated and extended their study by exploring possible explanations for these relationships, and by also investigating whether mind-wandering is related to (1) trait rumination subtype-brooding, depressive or reflective, and (2) trauma intrusions-a hallmark PTSD symptom, since both rumination and trauma intrusions strongly correlate with depression. We also explored if dispositional mindfulness-the opposing construct of mind-wandering-mediated these relationships.

METHOD

Two hundred participants completed mindfulness tendency and depression severity measures, counterbalanced with the Sustained Attention to Response Task (SART)-including thought probes to index behavioral mind-wandering (target-error frequency), subjective mind-wandering and meta-awareness-then the rumination style and trauma intrusion frequency measures.

RESULTS

Depression scores positively correlated with mind-wandering with and without meta-awareness and with SART target-error rates, and negatively correlated with dispositional mindfulness. Further, trait brooding positively correlated with mind-wandering without meta-awareness. Dispositional mindfulness mediated the relationships between brooding and depression, and depression and mind-wandering, and also negatively correlated with trauma intrusion frequency.

LIMITATIONS

Limitations include measurement and mind-wandering definitions, and an inability to make causal claims.

CONCLUSIONS

People experiencing greater depression symptomology, and/or who have a greater tendency to brood, mind-wandered more often. Further, people who experience more trauma intrusions tend to be less mindful. These results point to potential harmful effects of mind-wandering through people's reduced propensity to be mindful, facilitating a negative self-referenced cognitive loop that may maintain or increase depression.

Are Individuals Always Aware of Their Trauma-Related Intrusive Thoughts? A Study of Meta-Awareness

Individuals are not always aware of their mental content. We tested whether lack of awareness occurs in those who have experienced trauma, with and without posttraumatic stress disorder (PTSD). We also examined the role of proposed cognitive mechanisms (working memory and inhibition) in explaining unnoticed intrusions. Individuals with PTSD (n = 44), and varying levels of symptoms (high posttraumatic stress [PTS]: n = 24; low PTS: n = 37) reported on intrusive thoughts throughout a reading task. Intermittently, participants responded to probes about whether their thoughts were trauma related. Participants were "caught" engaging in unreported trauma-related thoughts (unnoticed intrusions) for between 24 and 27% of the probes in the PTSD and high PTS groups, compared with 15% of occasions in the low PTS group. For trauma-related intrusions only, participants lacked meta-awareness for almost 40% of probes in the PTSD group, which was significantly less than that observed in the other groups (∼60%). Contrary to predictions, working memory and response inhibition did not predict unnoticed intrusions. The results suggest that individuals who have experienced significant trauma can lack awareness about the frequency of their trauma-related thoughts. Further research is warranted to identify the mechanisms underpinning the occurrence of unnoticed intrusions.

Intrusive memories as conditioned responses to trauma cues: An empirically supported concept?

Intrusions in posttraumatic stress disorder (PTSD) are clinically understood as conditioned responses (CRs) to trauma-cues; however, experimental evidence for this is limited. We subjected 84 healthy participants to a differential conditioned-intrusion paradigm, where neutral faces served as conditioned stimuli (CSs) and aversive film clips as unconditioned stimuli (USs). While one group only completed acquisition, another group additionally received extinction. Subsequently, participants provided detailed e-diary intrusion reports. Several key findings emerged: First, participants in both groups re-experienced not only USs but also CSs as content of their intrusions. Second, intrusions were elicited by cues resembling CSs, USs, and experimental context. Third, extinction reduced probability and severity of US intrusions, and accelerated their decay, and this was particularly the case in participants showing greater cognitive (US-expectancy) and physiological (SCR) differential responding to CS+ vs. CS- at end of acquisition (i.e., conditionability). Similarly, extinction reduced CS-intrusion probability and severity, but only in participants with greater cognitive conditionability. These results support conditioning's role in re-experiencing in two critical ways: (1) Conditioning during trauma provides cues that not only function as reminder cues, but also as content of intrusions; (2) After strong conditioning, weakening the original CS-US relationship via extinction reduces intrusion formation after analogue-trauma.

Teaching During a Pandemic: A Model for Trauma-Informed Education and Administration

Coronavirus disease 2019 (COVID-19) realities have demanded that educators move swiftly to adopt new ways of teaching, advising, and mentoring. We suggest the centering of a trauma-informed approach to education and academic administration during the COVID-19 pandemic using the Substance Abuse and Mental Health Services Administration's (SAMHSA) guidance on trauma-informed approaches to care. In our model for trauma-informed education and administration (M-TIEA), SAMHSA's four key organizational assumptions are foundational, including a realization about trauma and its wide-ranging effects; a recognition of the basic signs and symptoms of trauma; a response that involves fully integrating knowledge into programs, policies, and practices; and an active process for resisting retraumatization. Since educators during the pandemic must follow new restrictions regarding how they teach, we have expanded the practice of teaching in M-TIEA to include both academic administrators' decision making about teaching, and educators' planning and implementation of teaching. In M-TIEA, SAMHSA's six guiding principles for a trauma-informed approach are infused into these two interrelated teaching processes, and include the following: safety; trustworthiness and transparency; peer support; collaboration and mutuality; empowerment, voice, and choice; and cultural, historical, and gender issues. M-TIEA's organizational assumptions, processes, and principles are situated within an outer context that acknowledges the potential influences of four types of intersectional traumas and stressors that may occur at multiple socioecological levels: pandemic-related trauma and stressors; other forms of individual, group, community, or mass trauma and stressors; historical trauma; and current general life stressors. This acknowledges that all trauma-informed work is dynamic and may be influenced by contextual factors.

Prospective associations between intelligence, working memory capacity, and intrusive memories of a traumatic film: Potential mediating effects of rumination and memory disorganization

BACKGROUND AND OBJECTIVES

Field research indicates that lower intelligence may predispose trauma-exposed individuals towards the development of re-experiencing symptoms. However, this assumption requires further testing in controlled prospective studies. In the current analog study, we tested whether lower fluid intelligence and lower working memory capacity (WMC) independently contribute to intrusion development. Moreover, we investigated potential mediating effects of trauma memory characteristics and trait rumination.

METHODS

118 healthy participants completed tests measuring fluid intelligence and WMC. Two days later, they were exposed to a film clip depicting traumatic events (i.e., so-called trauma film). After exposure to the film, intrusions were assessed using a diary and an intrusion triggering task.

RESULTS

Our analyses revealed a negative correlation between fluid intelligence and intrusions during the intrusion triggering task. WMC did not correlate with any intrusion measure. Moreover, planned analyses did not yield any mediation effects.

LIMITATIONS

We used the trauma film paradigm to examine analog posttraumatic stress symptoms. This approach limits the generalizability of our findings with regard to symptom development following real-life traumatic events.

CONCLUSIONS

Our results show for the first time that higher fluid intelligence is associated with fewer intrusions of a trauma film. This association was evident for laboratory but not for ambulatory intrusions. By demonstrating this association using a prospective experimental design, our study importantly corroborates previous field research.

Involuntary autobiographical memories and their relation to other forms of spontaneous thoughts

Involuntary autobiographical memories are memories of personal events that come to mind spontaneously-that is, with no conscious initiation of the retrieval process. Such spontaneously arising memories were long ignored in cognitive psychology, which generally has focused on controlled and strategic forms of remembering, studied in laboratory settings. Recent evidence shows that involuntary memories of past events are highly frequent in daily life, and that they represent a context-sensitive, and associative way of recollecting past events that involves little executive control. They operate by constraints that favour recent events and events with a distinct feature overlap to the current situation, which optimizes the probability of functional relevance to the ongoing situation. In addition to adults, they are documented in young children and great apes and may be an ontogenetic and evolutionary forerunner of strategic retrieval of past events. Findings suggest that intrusive involuntary memories observed clinically after traumatic events should be viewed as a dysfunctional subclass of otherwise functional involuntary autobiographical memories. Because of their highly constrained, situation-dependent and automatic nature, involuntary autobiographical memories form a distinct category of spontaneous thought that cannot be equated with mind wandering. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.

Traumatic Events and Substance Use Disorders in Adolescents

OBJECTIVES

Adolescents with substance use disorders (SUD) frequently report traumatic events (TEs) and symptoms of post-traumatic stress disorder (PTSD). This study aimed to assess whether lifetime prevalence rates of TEs and PTSD are related to SUD severity in adolescent psychiatric patients.

METHODS

We analyzed N = 114 self-reports of treatment-seeking German adolescents aged 12 to 18 years, who visited a specialized SUD outpatient unit. Standardized questionnaires were applied to assess SUD severity, the number of TEs and DSM-IV PTSD criteria.

RESULTS

Patients fulfilling PTSD criteria (28% of the total sample) had a higher Drug Use Disorders Identification Test (DUDIT) score compared to non-PTSD patients with TEs (p <.001), and compared to adolescents without TEs or PTSD (p = .003). Additionally, SUD severity was positively associated with the number of TEs and the number of intrusion, hyperarousal, and avoidance symptoms (all r = .33 to.48, all p <.01).

DISCUSSION

Adolescent patients with SUD reported 3-times higher rates of TEs, and a 5-time higher prevalence of PTSD following TEs, than the general adolescent population. Adolescent SUD patients with PTSD reported more severe substance use problems than patients without PTSD-regardless of previous TEs. Longitudinal studies are needed in order to investigate the temporal relationship between TEs, PTSD and SUD.

Intrusive memories and voluntary memory of a trauma film: Differential effects of a cognitive interference task after encoding

Methods to reduce intrusive memories (e.g., of traumatic events) should ideally spare voluntary memory for the same event (e.g., to report on the event in court). Single-trace memory accounts assume that interfering with a trace should impact both its involuntary and voluntary expressions, whereas separate-trace accounts assume these two can dissociate, allowing for selective interference. This possibility was investigated in 3 experiments. Nonclinical participants viewed a trauma film followed by an interference task (Tetris game-play after reminder cues). Next, memory for the film was assessed with various measures. The interference task reduced the number of intrusive memories (diary-based, Experiments 1 and 2), but spared performance on well-matched measures of voluntary retrieval-free recall (Experiment 1) and recognition (Experiments 1 and 2)-challenging single-trace accounts. The interference task did not affect other measures of involuntary retrieval-perceptual priming (Experiment 1) or attentional bias (Experiment 2). However, the interference task did reduce the number of intrusive memories in a laboratory-based vigilance-intrusion task (Experiments 2 and 3), irrespective of concurrent working memory load during intrusion retrieval (Experiment 3). Collectively, results reveal a robust dissociation between intrusive and voluntary memories, having ruled out key methodological differences between how these two memory expressions are assessed, namely cue overlap (Experiment 1), attentional capture (Experiment 2), and retrieval load (Experiment 3). We argue that the inability of these retrieval factors to explain the selective interference is more compatible with separate-trace than single-trace accounts. Further theoretical developments are needed to account for this clinically important distinction between intrusive memories and their voluntary counterpart. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Visual attentional load affects the frequency of involuntary autobiographical memories and their level of meta-awareness

Involuntary autobiographical memories (IAMs) are memories of past events that come to mind without deliberate retrieval attempts. Common in everyday life, IAMs have recently become a topic of experimental investigations with laboratory procedures. In the present study, we build on the recent methodological advancements in the study of IAMs, and we investigate the effects of manipulating the attentional load on the incidence of IAMs, as well as on the level of meta-awareness of these memories. In two experiments, attentional load was manipulated by varying the demands of the focal vigilance task, and reports of IAMs were collected. In Experiment 1, participants were instructed to stop the vigilance task whenever mental contents unrelated to the task came to their minds (self-caught method). In Experiment 2, participants were intermittently interrupted and probed regarding the contents of their experience (probe-caught method) and the level of meta-awareness for these contents. In both experiments, we found a reduction in the frequency of reported IAMs under increased attentional load. Moreover, in Experiment 2, IAMs were characterized by varied levels of meta-awareness, which was reduced by increased attentional load. These results indicate that allocation of attentional resources toward a focal task reduces reporting of IAMs experienced while performing this task because attentional resources play a role in both retrieval of IAMs and the realization that one is experiencing a memory.

Evidence That "Voluntary" Versus "Involuntary" Retrieval Is a Fluency-Based Attribution

Our memories can come to mind either voluntarily—after we intended to retrieve them—or, involuntarily—without our intent. Studies often rely upon subjects themselves to classify their memories as voluntary or involuntary. But how well do subjects perform this task? There is reason to suspect that subjects sometimes base these classifications of intent on feelings of fluency—that is, ease of retrieval—leading them to misclassify their memories. In four experiments, we investigated the extent to which making an experience of voluntary retrieval feel fluent leads subjects to ascribe involuntary attributes to that retrieval. Our findings provide the first experimental demonstration that when subjects intentionally, yet fluently, bring a memory to mind, they may mistakenly judge that the retrieval occurred without intent.

Frequency of Intrusions and Appraisal of Related Distress After Analogue Trauma: A Comparative Ecological Momentary Assessment Methods Study

Intrusive thoughts, images, and their appraisal remain difficult to study despite their clinical relevance. Clinical studies typically used time-based (frequency and distress per observation period), while analogue studies mainly used event-based (report upon occurrence) assessment. A comparison of intrusion frequency, distress appraisal, compliance, and reactivity across different assessments is mostly lacking, particularly with regard to analogue research. Here, intrusions were induced via aversive films and assessed by a smart phone application for 4 days. Three sampling modes were compared by randomizing participants to one of three conditions: either one, or five time-based daily prompts, or event-based assessment. At the end of the study, all participants reported intrusions once again in a retrospective summary assessment. Results indicate that intrusions and their distress decayed over a few days. The three assessments did not differ in intrusion frequency, distress appraisal, compliance (generally high), reactivity (generally low), or retrospective summary assessment. Across groups, the more aversive and arousing participants rated the film clips and the more reactivity to the electronic-diary assessment they reported, the more intrusive memories they had; assessment modes did not differ on this. Thus, no general differences were found between electronic-diary assessment modes for analogue intrusions, giving researchers flexibility for tailoring ecological momentary assessment to specific study aims.

Investigating the effect of proactive interference control training on intrusive memories

Intrusive re-experiencing is a hallmark symptom of Posttraumatic Stress Disorder (PTSD). According to prominent models of intrusive phenomena, intrusive memories may result from impairments in the efficiency of working memory capacity (WMC), more specifically proactive interference control. Yet, experimental research is scarce. Therefore, the present study aimed to investigate experimentally the role of proactive interference control in intrusive memories. We randomly assigned 57 healthy participants to either receive a high interference control training or a low interference control training. Participants were then exposed to highly distressing film clips. WMC was assessed before and after the training. Intrusion symptoms were assessed directly post-training and after one week using an Intrusion Provocation Task (IPT), a one-week intrusions diary, and the retrospective intrusion subscale of the Impact of Event Sale - Revised (IES-R). Results indicated that both groups reported improvements in WMC and fewer intrusions on the second IPT post-training, with no differences between groups. Similarly, no group differences on intrusions were found at one-week follow-up (i.e., intrusion diary and IES-R). To conclude, these data are not consistent with the hypothesis that WMC plays a role in intrusive re-experiencing. Implications for future research are discussed.

Towards a new methodological approach: A novel paradigm for covertly inducing and sampling different forms of spontaneous cognition

A wide range of cognitions is generated involuntarily in the human mind daily. We developed a paradigm, which covertly induces and samples spontaneous cognitions in the visual and auditory modalities, focusing on 3 key characteristics: spontaneity, repetition, and emotional valence. Sixty participants watched two visual clips while listening to music and assessed their characteristics. Post-induction, participants closed their eyes for 5 min and then completed a questionnaire, which indirectly samples different forms of spontaneous cognition. Induction was effective in all categories. Results indicated that different forms of spontaneous musical cognitions are experienced as longer in duration and less negative in emotional valence compared to visual cognitions. The findings are discussed in relation to spontaneous cognition methodology and experiences in different modalities. Spontaneous cognitions are multifaceted and not unitary constructs as previously considered and studied, and as such the novel induction and sampling paradigm presents a promising line of research.

Making remembering more memorable

Memory retrieval is a cognitive operation that itself can be remembered or forgotten, with potentially important consequences. To study memory for prior remembering, we had participants first study target words (e.g., bark) alongside semantically related cue words (e.g., dog). Then, on Test 1, participants retrieved targets in response to either the study cue or a changed cue that was semantically related to a homograph of the target (e.g., birch). Finally, on Test 2, participants retrieved all targets in response to the original study cues, and participants judged whether targets were previously retrieved on Test 1. As in previous research, cue change on Test 1 rendered target retrievals less memorable, suggesting context changes harm memory for prior remembering. We hypothesised that the negative effect of context change could be ameliorated by reminding participants of the original study cues during Test 1. We had participants either retrieve (Experiments 1 and 3, Ns = 46 and 62) or view (Experiment 2, N = 118) the study cue following each target retrieval. Reminding significantly reduced the negative effect of cue change, with self-generation being especially potent. This indicates that reminding can make remembering more memorable in the face of context change.

Repeated cortisol administration does not reduce intrusive memories - A double blind placebo controlled experimental study

PTSD is a severe mental disorder, which may develop after exposure to traumatic events and is characterized by intrusive memories. Intrusions are sudden brief sensory memories of the traumatic event, that cause immense distress and impairment in every day functioning. Thus, the reduction of intrusive memories is one of the main aims of PTSD therapy. Recently, the glucocorticoid cortisol has been proposed as a pharmacological option to reduce intrusive memories, because cortisol is known to have memory retrieval inhibiting effects. However, the research on the effects of cortisol administration on intrusive memories is not conclusive. The aim of the present study was to examine if repeated cortisol administration inhibits intrusions and recognition memory in an experimental study using the trauma film paradigm. In a randomized double-blind placebo controlled design participants were exposed to a traumatic film (known to induce intrusions in healthy participants) and received either a low dose of cortisol (20mg) or placebo on the three days following "trauma exposure". Intrusive memories were assessed with an Electronic Diary and an Intrusion Triggering Task. Furthermore, we assessed explicit memory for the traumatic film clip with a recognition test. Contrary to our predictions, the cortisol group did not report fewer intrusions than the placebo group nor did it show diminished performance on the recognition test. Our results show that sole cortisol administration after a traumatic experience cannot reduce intrusive re-experiencing.

Tracking Deceased-Related Thinking with Neural Pattern Decoding of a Cortical-Basal Ganglia Circuit

BACKGROUND

Deceased-related thinking is central to grieving and potentially critical to processing of the loss. Self-report measurements might fail to capture important elements of deceased-related thinking and processing. Here, we used a machine learning approach applied to fMRI - known as neural decoding - to develop a measure of ongoing deceased-related processing.

METHODS

23 subjects grieving the loss of a first-degree relative, spouse or partner within 14 months underwent two fMRI tasks. They first viewed pictures and stories related to the deceased, a living control and a demographic control figure while providing ongoing valence and arousal ratings. Second, they performed a 10-minute Sustained Attention to Response Task (SART) with thought probes every 25-35 seconds to identify deceased, living and self-related thoughts.

RESULTS

A conjunction analysis, controlling for valence/arousal, identified neural clusters in basal ganglia, orbital prefrontal cortex and insula associated with both types of deceased-related stimuli vs. the two control conditions in the first task. This pattern was applied to fMRI data collected during the SART, and discriminated deceased-related but not living or self-related thoughts, independently of grief-severity and time since loss. Deceased-related thoughts on the SART correlated with self-reported avoidance. The neural model predicted avoidance over and above deceased-related thoughts.

CONCLUSIONS

A neural pattern trained to identify mental representations of the deceased tracked deceased-related thinking during a sustained attention task and also predicted subject-level avoidance. This approach provides a new imaging tool to be used as an index of processing the deceased for future studies of complicated grief.

A prospective examination of risk factors in the development of intrusions following a trauma analog

Several factors have been linked to the severity of posttraumatic distress, although retrospective designs in much of the literature limit conclusions regarding the temporal relation between risk factors and corresponding symptoms. To address these concerns, the current project employed an analog trauma paradigm to assess the impact of background characteristics, stress response, and post-stressor affect regulation on subjective distress and intrusive memories experienced during the subsequent processing of emotional stimuli. University students (N = 184; 56% female, 42% White/Non-Hispanic) were shown graphic scenes of a televised suicide. Physiological activation was recorded during exposure with emotion ratings collected following the film. Participants then viewed a sadness- or humor-eliciting prime under instructions to inhibit or naturally express emotion. Intrusions experienced during the priming film and residual distress at study's conclusion were rated prior to debriefing. Hierarchical regression identified reductions in emotional valence as a robust predictor of intrusions and distress. Sympathetic activation and exposure to the sadness prime were associated with intrusion frequency, whereas attenuated parasympathetic response predicted intrusion intensity. Expressive inhibition demonstrated a unique association with residual distress. Results suggest peritraumatic processes and post-exposure factors may hold more prominent relations with immediate trauma-related distress as compared to pre-existing survivor characteristics.

Do meta-cognitive beliefs affect meta-awareness of intrusive thoughts about trauma?

BACKGROUND AND OBJECTIVES

People exposed to trauma often experience intrusive thoughts and memories about that event. Research examining people's responses to trauma assumes that people can accurately notice the occurrence of symptoms. However, we know from the broader cognitive literature on 'mind-wandering' that people are not always aware of their current focus of attention. That lack of awareness has implications for our theoretical and practical understanding of how trauma survivors recover from their experience. In the current study we investigated whether people's meta-cognitive beliefs about controlling trauma-related intrusions influenced the occurrence and meta-awareness of those intrusions.

METHODS

We recruited participants who scored high (strong beliefs) or low (weak beliefs) on beliefs regarding the importance of controlling intrusive thoughts. Participants viewed a trauma film then-during a subsequent reading task-reported any film-related intrusions they noticed. We also intermittently asked half the participants to report what they were thinking at that particular moment, to "catch" intrusions without meta-awareness.

RESULTS

People are not always aware of their trauma intrusions, and importantly, people with strong beliefs are more likely to notice trauma related intrusions both with and without meta-awareness than people with weak beliefs.

LIMITATIONS

We used an analogue trauma, and focused on a particular metacognitive belief, both of which somewhat limit generalizability. We also cannot definitively rule out demand effects.

CONCLUSIONS

Our data add to existing research showing people may lack meta-awareness of trauma-related thoughts, and suggest that survivors with particular metacognitive characteristics may be more vulnerable to 'mind-wandering' about trauma without awareness.

Posttraumatic Stress Disorder and Autobiographical Memories in Everyday Life

Evidence from self-reports and laboratory studies suggests that recall of nontrauma autobiographical memories may be disturbed in posttraumatic stress disorder (PTSD), but investigations in everyday life are sparse. This study investigated unintentional nontrauma and trauma memories in trauma survivors with and without PTSD (N = 52), who kept an autobiographical memory diary for a week. We investigated whether unintentional nontrauma memories show an overgeneral memory bias and further memory abnormalities in people with PTSD, and whether unintentional trauma memories show distinct features. Compared to the no-PTSD group, the PTSD group recorded fewer nontrauma memories, which were more overgeneral, more often from before the trauma or related to the trauma, were perceived as distant, and led to greater dwelling. Trauma memories were more vivid, recurrent, and present and led to greater suppression and dwelling. Within the PTSD group, the same features distinguished trauma and nontrauma memories. Results are discussed regarding theories of autobiographical memory and PTSD.

The relationship between suppression and subsequent intrusions: the mediating role of peritraumatic dissociation and anxiety

BACKGROUND AND OBJECTIVES

Although previous studies showed that thought and emotion suppression represent risk factors for intrusions development, the mechanisms that explain these relations were less explored. This study aims to examine the relationships between thought and emotion suppression and the symptoms of intrusion following the exposure to a trauma-related event. Moreover, we explored if these relationships would be mediated by peritraumatic state dissociation and state anxiety.

DESIGN AND METHODS

The trauma film paradigm was used and the participants were students (N = 148) experimentally exposed to an aversive film to model a traumatic experience. Thought and emotion suppression were measured before the trauma exposure. After exposure, the participants completed scales for measuring state dissociation and state anxiety. Intrusive images and thoughts of the film were recorded in the subsequent week using an intrusion diary.

RESULTS

Thought suppression predicted intrusive thoughts frequency, and this effect was mediated by the peritraumatic anxiety. State anxiety predicted both intrusive images and thoughts, while state dissociation only predicted intrusive images.

CONCLUSIONS

Intrusive images and intrusive thoughts are different phenomena and they are predicted by different variables. The practical implications of these results for posttraumatic stress disorder treatment and secondary traumatization are discussed.

Impact of exogenous cortisol on the formation of intrusive memories in healthy women

INTRODUCTION

Stress hormones such as cortisol are involved in modulating emotional memory. However, little is known about the influence of cortisol on the formation of intrusive memories after a traumatic event. The aim of this study was to examine whether cortisol levels during encoding and consolidation of an intrusion-inducing trauma film paradigm would influence subsequent intrusion formation.

MATERIAL AND METHODS

In an experimental, double-blind, placebo-controlled study a trauma film paradigm was used to induce intrusions in 60 healthy women. Participants received a single dose of either 20 mg hydrocortisone or placebo before watching a trauma film. Salivary cortisol and alpha-amylase as well as blood pressure were measured during the experiment. The consecutive number of intrusions, the vividness of intrusions, and the degree of distress evoked by the intrusions resulting from the trauma film were assessed throughout the following seven days.

RESULTS

Hydrocortisone administration before the trauma film resulted in increased salivary cortisol levels but did not affect the consecutive number of intrusions, the vividness of intrusions, and the degree of distress evoked by the intrusions throughout the following week.

CONCLUSIONS

These results indicate that pharmacologically increased cortisol levels during an experimental trauma film paradigm do not influence consecutive intrusive memories. Current data do not support a prominent role of exogenous cortisol on intrusive memories, at least in healthy young women after a relatively mild trauma equivalent.

Influence of the noradrenergic system on the formation of intrusive memories in women: an experimental approach with a trauma film paradigm

BACKGROUND

Intrusive memories of traumatic events are a core feature of post-traumatic stress disorder but little is known about the neurobiological formation of intrusions. The aim of this study was to determine whether the activity of the noradrenergic system during an intrusion-inducing stressor would influence subsequent intrusive memories.

METHOD

We conducted an experimental, double-blind, placebo-controlled study in 118 healthy women. Participants received a single dose of either 10 mg yohimbine, stimulating noradrenergic activity, or 0.15 mg clonidine, inhibiting noradrenergic activity, or placebo. Subsequently, they watched an established trauma film which induced intrusions. The number of consecutive intrusions resulting from the trauma film, the vividness of the intrusions, and the degree of distress evoked by the intrusions were assessed during the following 4 days. Salivary cortisol and α-amylase were collected before and after the trauma film.

RESULTS

A significant time × treatment interaction for the number of intrusions and the vividness of intrusions indicated a different time course of intrusions depending on treatment. Post-hoc tests revealed a delayed decrease of intrusions and a delayed decrease of intrusion vividness after the trauma film in the yohimbine group compared with the clonidine and placebo groups. Furthermore, after yohimbine administration, a significant increase in salivary cortisol levels was observed during the trauma film.

CONCLUSIONS

Our findings indicate that pharmacological activation of the noradrenergic system during an emotionally negative event makes an impact on consecutive intrusive memories and their vividness in healthy women. The noradrenergic system seems to be involved in the formation of intrusive memories.

Intrusive Cognitive Content and Postdeployment Distress

Although intrusive cognitions (ICs) are common posttrauma, little is known about trauma-related IC content, or associations between IC content and posttraumatic adjustment. A mixed-method cross-sectional approach was used in a secondary analysis of IC content and postdeployment distress. Participants were 1,521 U.S. Army soldiers 3-12 months postdeployment reporting their most distressing postdeployment ICs (mean number of ICs reported was 1.20). ICs were transcribed and content was categorized by 13 emergent themes. The most commonly reported ICs were of injury or death (48.2%) and combat (43.5%), and soldiers with probable posttraumatic stress disorder (PTSD; n = 187) were more likely to report the presence of these ICs, χ(2) s(1) = 35.27, ps < .001, φs < .16 than those without probable PTSD (n = 1,331). Other domains also emerged frequently, including ICs about friends (31.0%), family (15.8%), and leadership concerns (13.8%). IC content was a small, but significant correlate of distress after adjusting for combat exposure (ΔR(2) ≥ .02, ps ≤ .001). The presence of ICs of injury or death, combat, military sexual trauma, health, leadership, and family (βs > .06, ps < .02) were unique correlates of distress. Results suggested that ICs about a wide range of topics should be addressed in postdeployment interventions.

From mind wandering to involuntary retrieval: Age-related differences in spontaneous cognitive processes

The majority of studies that have investigated the effects of healthy aging on cognition have focused on age-related differences in voluntary and deliberately engaged cognitive processes. Yet many forms of cognition occur spontaneously, without any deliberate attempt at engaging them. In this article we review studies that have assessed age-related differences in four such types of spontaneous thought processes: mind-wandering, involuntary autobiographical memory, intrusive thoughts, and spontaneous prospective memory retrieval. These studies suggest that older adults exhibit a reduction in frequency of both mind-wandering and involuntary autobiographical memory, whereas findings regarding intrusive thoughts have been more mixed. Additionally, there is some preliminary evidence that spontaneous prospective memory retrieval may be relatively preserved in aging. We consider the roles of age-related differences in cognitive resources, motivation, current concerns and emotional regulation in accounting for these findings. We also consider age-related differences in the neural correlates of spontaneous cognitive processes.

Minds "at attention": mindfulness training curbs attentional lapses in military cohorts

We investigated the impact of mindfulness training (MT) on attentional performance lapses associated with task-unrelated thought (i.e., mind wandering). Periods of persistent and intensive demands may compromise attention and increase off-task thinking. Here, we investigated if MT may mitigate these deleterious effects and promote cognitive resilience in military cohorts enduring a high-demand interval of predeployment training. To better understand which aspects of MT programs are most beneficial, three military cohorts were examined. Two of the three groups were provided MT. One group received an 8-hour, 8-week variant of Mindfulness-based Mind Fitness Training (MMFT) emphasizing engagement in training exercises (training-focused MT, n = 40), a second group received a didactic-focused variant emphasizing content regarding stress and resilience (didactic-focused MT, n = 40), and the third group served as a no-training control (NTC, n = 24). Sustained Attention to Response Task (SART) performance was indexed in all military groups and a no-training civilian group (CIV, n = 45) before (T1) and after (T2) the MT course period. Attentional performance (measured by A’, a sensitivity index) was lower in NTC vs. CIV at T2, suggesting that performance suffers after enduring a high-demand predeployment interval relative to a similar time period of civilian life. Yet, there were significantly fewer performance lapses in the military cohorts receiving MT relative to NTC, with training-focused MT outperforming didactic-focused MT at T2. From T1 to T2, A’ degraded in NTC and didactic-focused MT but remained stable in training-focused MT and CIV. In sum, while protracted periods of high-demand military training may increase attentional performance lapses, practice-focused MT programs akin to training-focused MT may bolster attentional performance more than didactic-focused programs. As such, training-focused MT programs should be further examined in cohorts experiencing protracted high-demand intervals.

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.