Rethinking post-traumatic stress disorder - A predictive processing perspective

Enhancing Agency in Posttraumatic Stress Disorder Therapies through Sensorimotor technologies

UNSTRUCTURED

Posttraumatic stress disorder (PTSD) is a significant public health concern, with only a third of patients recovering within a year of treatment. While PTSD often disrupts the sense of body ownership and the sense of agency (SA), attention to SA in trauma has been lacking. This perspective article explores the loss of SA in PTSD and its relevance in the development of symptoms. Trauma is viewed as a breakdown of SA, related to a freeze response, with peritraumatic dissociation increasing the risk of PTSD. Drawing from embodied cognition, we propose an "enactive" perspective of PTSD, suggesting therapies that restore the SA through direct engagement with the body and environment. We discuss the potential of agency-based therapies and innovative technologies like gesture sonification (GS), which translates body movements into sounds to enhance the SA. GS offers a screen-free, non-invasive approach that could complement existing trauma-focused therapies. We emphasize the need for interdisciplinary collaboration and clinical research to further explore these approaches in preventing and treating PTSD.

Understanding trauma as contextualized adverse life events that threaten the individual: Commentary in response to Marx et al. (2024)

In this commentary, I propose that a person-oriented and research-focused approach can stimulate the discussion on the definition of a traumatic stressor and help to refine Criterion A in the Diagnostic and Statistical Manual of Mental Disorders (DSM). Particularly, I suggest that a contextual perspective focusing on the interaction between event features and person-related factors captures more adequately the individual perception of and cognitions related to extremely threatening adverse life events for a diversity of individuals exposed to trauma. In future debate, I encourage the involvement of patients and the public and urge consideration of all potential consequences for practice and research that can directly result from changes to Criterion A (e.g., the heterogenization of posttraumatic stress disorder).

Does disconfirmatory evidence shape safety-and danger-related beliefs of trauma-exposed individuals?

Recent accounts of predictive processing in posttraumatic stress disorder (PTSD) suggest that trauma-exposed individuals struggle to update trauma-related hypotheses predicting danger, which may be involved in the etiology and maintenance of this disorder. Initial research supports this account, documenting an association between trauma-exposure, impaired expectation updating, and PTSD symptoms. Yet, no study to date has examined biased belief updating in PTSD using a scenario-based approach.Objective: Here, we examined the predictive processing account among trauma-exposed and non-trauma-exposed individuals using a modified Trauma-Related version of the Bias Against Disconfirmatory Evidence task.Method: The task presents both danger-and safety-related scenarios highly relevant for trauma-exposed individuals. For each scenario, participants viewed several explanations and rated their plausibility. Their ability to update their initial interpretation following new-contradictory information was assessed.Results: Preregistered analyses did not reveal any significant findings. Based on indications that our sample may not have been sufficiently powered, we conducted exploratory analyses in an extended sample of participants. These analyses yielded a significant association between reduced belief updating and PTSD symptoms which was evident for disconfirming both safety and danger scenarios. However, the effect sizes we found were in the small-to-medium range.Conclusion: Although preliminary, our current findings support initial evidence that individuals with higher PTSD symptoms show a higher resistance to update their beliefs upon new disconfirmatory evidence. Our results should be interpreted cautiously in light of the extended sample and the limitations of the current study.

Altered long-range functional connectivity in PTSD: Role of the infraslow oscillations of cortical activity amplitude envelopes

OBJECTIVE

Coupling between the amplitude envelopes (AEs) of regional cortical activity reflects mechanisms that coordinate the excitability of large-scale cortical networks. We used resting-state MEG recordings to investigate the association between alterations in the coupling of cortical AEs and symptoms of post-traumatic stress disorder (PTSD).

METHODS

Participants (n = 96) were service members with combat exposure and various levels of post-traumatic stress severity (PTSS). We assessed the correlation between PTSS and (1) coupling of broadband cortical AEs of beta band activity, (2) coupling of the low- (<0.5 Hz) and high-frequency (>0.5 Hz) components of the AEs, and (3) their time-varying patterns.

RESULTS

PTSS was associated with widespread hypoconnectivity assessed from the broadband AE fluctuations, which correlated with subscores for the negative thoughts and feelings/emotional numbing (NTF/EN) and hyperarousal clusters of symptoms. Higher NTF/EN scores were also associated with smaller increases in resting-state functional connectivity (rsFC) with time during the recordings. The distinct patterns of rsFC in PTSD were primarily due to differences in the coupling of low-frequency (infraslow) fluctuations of the AEs of beta band activity.

CONCLUSIONS

Our findings implicate the mechanisms underlying the regulation/coupling of infraslow oscillations in the alterations of rsFC assessed from broadband AEs and in PTSD symptomatology.

SIGNIFICANCE

Altered coordination of infraslow amplitude fluctuations across large-scale cortical networks can contribute to network dysfunction and may provide a target for treatment in PTSD.

Can computational models help elucidate the link between complex trauma and hallucinations?

Recently, a number of predictive coding models have been proposed to account for post-traumatic stress disorder (PTSD)'s symptomatology, including intrusions, flashbacks and hallucinations. These models were usually developed to account for traditional/type-1 PTSD. We here discuss whether these models also apply or can be translated to the case of complex/type-2 PTSD and childhood trauma (cPTSD). The distinction between PTSD and cPTSD is important because the disorders differ in terms of symptomatology and potential mechanisms, how they relate to developmental stages, but also in terms of illness trajectory and treatment. Models of complex trauma could give us insights on hallucinations in physiological/pathological conditions or more generally on the development of intrusive experiences across diagnostic classes.

Individual prediction tendencies do not generalize across modalities

Predictive processing theories, which model the brain as a "prediction machine", explain a wide range of cognitive functions, including learning, perception and action. Furthermore, it is increasingly accepted that aberrant prediction tendencies play a crucial role in psychiatric disorders. Given this explanatory value for clinical psychiatry, prediction tendencies are often implicitly conceptualized as individual traits or as tendencies that generalize across situations. As this has not yet explicitly been shown, in the current study, we quantify to what extent the individual tendency to anticipate sensory features of high probability generalizes across modalities. Using magnetoencephalography (MEG), we recorded brain activity while participants were presented with a sequence of four different (either visual or auditory) stimuli, which changed according to predefined transitional probabilities of two entropy levels: ordered vs. random. Our results show that, on a group-level, under conditions of low entropy, stimulus features of high probability are preactivated in the auditory but not in the visual modality. Crucially, the magnitude of the individual tendency to predict sensory events seems not to correlate between the two modalities. Furthermore, reliability statistics indicate poor internal consistency, suggesting that the measures from the different modalities are unlikely to reflect a single, common cognitive process. In sum, our findings suggest that quantification and interpretation of individual prediction tendencies cannot be generalized across modalities.

The relationship between multiple traumatic events and the severity of posttraumatic stress disorder symptoms – evidence for a cognitive link

Background: Previous research has shown that multiple traumatic experiences cumulatively increase the risk for the development of severe symptoms of posttraumatic stress disorder (PTSD). Yet, little is known about the specific psychological mechanism through which this increased risk comes about.Objective: In the present study, we examined a possible cognitive link between multiple traumatic events and PTSD symptom severity through dysfunctional cognitions and expectations.Methods: A sample of patients with a diagnosed PTSD (N = 70; M_Age= 42.06; 82% female) and high symptom burden (IES-R M = 79.24) was examined. On average, patients had experienced 5.31 different traumatic events. In a structural equation model, we tested the hypothesis that the relationship between multiple traumatic experiences and PTSD symptom severity is mediated through dysfunctional general cognitions and dysfunctional situation-specific expectations. General trauma-related cognitions were assessed with the Posttraumatic Cognition Inventory (PTCI) and trauma-related situational expectations were assessed with the Posttraumatic Expectations Scale (PTES).Results: The direct effect of the number of traumatic events on PTSD symptom severity was non-significant. Instead, as hypothesised, there was evidence for a significant indirect effect via dysfunctional general cognitions and situation-specific expectations.Conclusions: The current results further specify the cognitive model of PTSD by indicating that the relationship between the number of traumatic events and PTSD symptom severity is mediated through dysfunctional cognitions and expectations. These findings emphasise the importance of focused cognitive treatment approaches that seek to modify dysfunctional cognitions and expectations in people with multiple traumatic experiences.

Posttraumatic reexperiencing and alcohol use: mediofrontal theta as a neural mechanism for negative reinforcement

Objective

Over half of US military veterans with posttraumatic stress disorder (PTSD) use alcohol heavily, potentially to cope with their symptoms. This study investigated the neural underpinnings of PTSD symptoms and heavy drinking in veterans. We focused on brain responses to salient outcomes within predictive coding theory. This framework suggests the brain generates prediction errors (PEs) when outcomes deviate from expectations. Alcohol use might provide negative reinforcement by reducing the salience of negatively-valenced PEs and dampening experiences like loss.

Methods

We analyzed electroencephalography (EEG) responses to unpredictable gain/loss feedback in veterans of Operations Enduring and Iraqi Freedom. We used time-frequency principal components analysis of event-related potentials to isolate neural responses indicative of PEs, identifying mediofrontal theta linked to losses (feedback-related negativity, FRN) and central delta associated with gains (reward positivity, RewP).

Results

Intrusive reexperiencing symptoms of PTSD were associated with intensified mediofrontal theta signaling during losses, suggesting heightened negative PE sensitivity. Conversely, increased hazardous alcohol use was associated with reduced theta responses, implying a dampening of these negative PEs. The separate delta-RewP component showed associations with alcohol use but not PTSD symptoms.

Conclusions

Findings suggest a common neural component of PTSD and hazardous alcohol use involving altered PE processing. We suggest that reexperiencing enhances the intensity of salient negative PEs, while chronic alcohol use may reduce their intensity, thereby providing negative reinforcement by muting emotional disruption from reexperienced trauma. Modifying the mediofrontal theta response could address the intertwined nature of PTSD symptoms and alcohol use, providing new avenues for treatment.

Cognitive flexibility moderates the efficacy of a visuospatial intervention following exposure to analog trauma

BACKGROUND AND OBJECTIVES

Intrusive memories are the hallmark feature of Post-Traumatic-Stress-Disorder (PTSD). Recent studies show that a visuospatial intervention after viewing traumatic films reduces intrusive memories in healthy individuals. However, many individuals still exhibit high levels of symptoms following such an intervention, warranting continued investigation into specific characteristics moderating intervention effect. One such candidate is cognitive-flexibility, defined as the ability to update behavior according to contextual demands. The present study examined the interactive effect of cognitive-flexibility and a visuospatial intervention on intrusive memories, predicting that higher flexibility would be associated with stronger intervention effects.

METHODS

Sixty participants (Mage = 29.07, SD = 4.23) completed a performance-based paradigm evaluating cognitive-flexibility, watched traumatic films, and were allocated to either an intervention or a no-task control group. Intrusions were assessed by means of laboratory and ambulatory assessment, and the intrusion subscale of the Impact-of-Events-Scale-Revised (IES-R).

RESULTS

Participants in the intervention group experienced fewer laboratory intrusions than the control group. However, this effect was moderated by cognitive-flexibility: Whereas individuals with below-average cognitive-flexibility did not benefit from the intervention, it was significantly beneficial for individuals with average and above-average cognitive-flexibility. No group differences emerged in the number of ambulatory intrusions or IES-R scores. However, cognitive-flexibility was negatively correlated with IES-R scores across both groups.

LIMITATIONS

The analog design may limit the extent of generalization to real-world traumatic events.

CONCLUSIONS

These results point to a potentially beneficial effect of cognitive-flexibility on intrusion development, particularly in the context of visuospatial interventions.

Reducing intrusive memories after trauma via an imagery-competing task intervention in COVID-19 intensive care staff: a randomised controlled trial

Intrusive memories (IMs) after traumatic events can be distressing and disrupt mental health and functioning. We evaluated the impact of a brief remotely-delivered digital imagery-competing task intervention on the number of IMs for intensive care unit (ICU) staff who faced repeated trauma exposure during the COVID-19 pandemic using a two-arm, parallel-group, single-blind randomised controlled trial, with the comparator arm receiving delayed access to active treatment (crossover). Eligible participants worked clinically in a UK NHS ICU during the pandemic and had at least 3 IMs of work-related traumatic events in the week before recruitment. Participants were randomly assigned (1:1) to immediate (weeks 1-4) or delayed (weeks 5-8) intervention access. Sequential Bayesian analyses to optimise the intervention and increase trial efficiency are reported elsewhere [1]. The primary endpoint for the pre-specified frequentist analysis of the final study population compared the number of IMs experienced in week 4 between the immediate and delayed access arms. Secondary outcomes included clinical symptoms, work functioning and wellbeing. Safety was assessed throughout the trial by scheduled questions and free report. All analyses were undertaken on an intention-to-treat basis (86 randomised participants). There were significantly fewer intrusive memories during week 4 in the immediate (median = 1, IQR = 0-3, n = 43), compared to the comparator delayed arm (median = 10, IQR = 6-17, n = 43), IRR 0.31, 95% CI: 0.20-0.48, p < 0.001. After crossover, the delayed arm also showed a significant reduction in IMs at week 8 compared to week 4. There were convergent findings for symptoms of PTSD, insomnia and anxiety, work engagement and burnout, general functioning and quality of life. The intervention was found safe and acceptable to participants. All adverse events were unrelated to the study. Our study provides the first evidence of a benefit on reducing IMs, improving other clinical symptoms, work functioning and wellbeing, as well as safety of a brief remotely-delivered digital imagery-competing task intervention. An efficacy trial with an active control and longer follow-up is warranted. The trial is registered at ClinicalTrials.gov (NCT04992390).

To sleep or not to sleep, that is the question: A systematic review and meta-analysis on the effect of post-trauma sleep on intrusive memories of analog trauma

Distressing intrusive memories of a traumatic event are one of the hallmark symptoms of posttraumatic stress disorder. Thus, it is crucial to identify early interventions that prevent the occurrence of intrusive memories. Both, sleep and sleep deprivation have been discussed as such interventions, yet previous studies yielded contradicting effects. Our systematic review aims at evaluating existing evidence by means of traditional and individual participant data (IPD) meta-analyses to overcome power issues of sleep research. Until May 16th, 2022, six databases were searched for experimental analog studies examining the effect of post-trauma sleep versus wakefulness on intrusive memories. Nine studies were included in our traditional meta-analysis (8 in the IPD meta-analysis). Our analysis provided evidence for a small effect favoring sleep over wakefulness, log-ROM = 0.25, p < .001, suggesting that sleep is associated with a lower number of intrusions but unrelated to the occurrence of any versus no intrusions. We found no evidence for an effect of sleep on intrusion distress. Heterogeneity was low and certainty of evidence for our primary analysis was moderate. Our findings suggest that post-trauma sleep has the potential to be protective by reducing intrusion frequency. More research is needed to determine the impact following real-world trauma and the potential clinical significance.

Assessing Dysfunctional Expectations in Posttraumatic Stress Disorder: Development and Validation of the Posttraumatic Expectations Scale (PTES)

Dysfunctional expectations are a particularly important subset of cognitions that influence the development and maintenance of various mental disorders. This study aimed to develop and validate a scale to assess dysfunctional expectations in posttraumatic stress disorder (PTSD), the "Posttraumatic Expectations Scale" (PTES). In a cross-sectional study, 70 PTSD patients completed the PTES, the Posttraumatic Cognitions Inventory (PTCI), as well as measures of the severity of symptoms of PTSD and depression. The results show that the PTES has excellent internal consistency and correlates significantly with the PTCI and PTSD symptom severity. A regression analysis revealed that the PTES explained variance of PTSD symptom severity above the PTCI, supporting the incremental validity of the PTES. While the original version of the PTES comprises 81 items, short scales were constructed using the BISCUIT (best items scales that are cross-validated, unit-weighted, informative and transparent) method. The current findings provide preliminary psychometric evidence suggesting that the PTES is an internally consistent and valid novel self-report measure in patients with PTSD. However, conclusions about the psychometric properties of the PTES are limited because of the absence of criterion-related validity, factor structure evidence, variability over time/response to intervention, and test-retest reliability. Future research should use the PTES in large-scale longitudinal studies to address these aspects to further validate the scale.

The role of cognitive flexibility in moderating the effect of school-related stress exposure

Educators are exposed to various stressful events as part of their ongoing work, including violence, sexual assaults, suicidal behavior, and loss or illness of students or their family members. Previous studies revealed an increased risk of developing PTSD symptoms in healthcare and supportive professionals exposed to repeated stress as part of their work. Cognitive flexibility might be a protective factor against the negative effect of such stress. The current study aimed to examine the interactive effects of school-related stress exposure and cognitive flexibility on the tendency to develop Post Traumatic Stress Disorder (PTSD) symptoms and the coping abilities of educators. One hundred and fifty educators (86.5% female; M_age = 43.08, M_{teaching_experience} = 12.90) volunteered to participate in this study. They completed questionnaires measuring levels of stress exposure, cognitive flexibility, coping ability, and PTSD symptoms. Analyses revealed that cognitive flexibility moderated the relationship between school-related stress exposure and both PTSD symptoms severity and maladaptive coping. Specifically, whereas educators with low cognitive flexibility exhibited positive associations between continuous stress exposure and both levels of PTSD symptoms and maladaptive coping, no such association was found among educators with high cognitive flexibility. The results highlight the importance of cognitive flexibility as a protective factor against the harmful effects of possible stress exposure in school environments. Awareness of the crucial role of cognitive flexibility as a protective factor for educators can be a breakthrough in improving educators' well-being and adaptive functioning.

Anhedonia and sensitivity to punishment in schizophrenia, depression and opiate use disorder

BACKGROUND

From a behavioural perspective anhedonia is defined as diminished interest in the engagement of pleasurable activities. Despite its presence across a range of psychiatric disorders, the cognitive processes that give rise to anhedonia remain unclear.

METHODS

Here we examine whether anhedonia is associated with learning from positive and negative outcomes in patients diagnosed with major depression, schizophrenia and opiate use disorder alongside a healthy control group. Responses in the Wisconsin Card Sorting Test - a task associated with healthy prefrontal cortex function - were fitted to the Attentional Learning Model (ALM) which separates learning from positive and negative feedback.

RESULTS

Learning from punishment, but not from reward, was negatively associated with anhedonia beyond other socio-demographic, cognitive and clinical variables. This impairment in punishment sensitivity was also associated with faster responses following negative feedback, independently of the degree of surprise.

LIMITATIONS

Future studies should test the longitudinal association between punishment sensitivity and anhedonia also in other clinical populations controlling for the effect of specific medications.

CONCLUSIONS

Together the results reveal that anhedonic subjects, because of their negative expectations, are less sensitive to negative feedbacks; this might lead them to persist in actions leading to negative outcomes.

Warning signals? An explorative study of distant recollections of the moments before a disaster

Background: How do we remember what happened shortly before a traumatic experience? There has been little focus on the temporal context of trauma memories, but a few studies suggest that aspects of what happened in the moments prior to a traumatic experience may be selectively enhanced and prioritized in memory.Objective: The main aim of this study was to investigate the occurrence, nature, and content of voluntary memories about what happened shortly before a disaster. The participants were individuals who had survived a fire on the passenger ferry Scandinavian Star 26 years earlier.Methods: Data collection took the form of face-to-face interviews. The analysis was carried out in two steps. First, all the narratives from participants who were aged 7 years or older at the time of the fire (N = 86) were coded in terms of the presence of detailed descriptions of what happened before the fire. Next, the narratives that included detailed descriptions of the moments before (N = 28) were included in a thematic analysis, focusing on coding the mode and the content.Results: More than one-third of the participants reported detailed accounts of what happened in the hours, minutes, or seconds before the fire. These memories included detailed descriptions of sensory impressions, dialogues, actions, and thoughts. Two themes stood out in the thematic analysis: (1) unusual observations and danger cues; and (2) counterfactual thoughts.Conclusion: The finding that specific details from the moments before a traumatic event may be vividly recalled indicates that peripheral details of traumatic events can be prioritized in memory. Such details may be interpreted as warning signals. Future research should examine whether such memories might stimulate long-standing thoughts of the world as being dangerous, and hence carry the threat forward in time.

Understanding the relationships between trauma type and individual posttraumatic stress symptoms: a cross-sectional study of a clinical sample of children and adolescents

BACKGROUND

Characteristics of traumatic events may be associated with the level and specific manifestation of posttraumatic stress symptoms (PTSS). This study examined the differences and similarities between overall levels, profiles and networks of PTSS after sexual trauma, domestic violence, community violence, non-interpersonal trauma, sudden loss or serious illness of a loved one, and severe bullying or threats.

METHODS

PTSS were measured in a clinical sample of 4,921 children and adolescents (6-18 years old, M = 14.0, SD = 2.7, 63.7% female) referred to Child and Adolescent Mental Health Services. We compared 95% confidence intervals (CI) for each symptom with 95% CI for overall PTSS within each trauma type (self-reported worst trauma). We also computed cross-sectional networks and searched for differences in networks according to trauma type and overall symptom level.

RESULTS

The overall frequencies of PTSS were highest following sexual trauma; somewhat lower for domestic violence and severe bullying or threats and lowest after community violence, non-interpersonal trauma and sudden loss or serious illness. Psychological cue reactivity, avoidance and difficulties with sleeping and concentrating were generally among the most frequent symptoms. Sexual trauma, domestic violence and severe bullying or threats were associated with higher frequencies of negative beliefs and persistent negative emotional states. Few differences in symptom networks across trauma type emerged.

CONCLUSION

Different types of trauma exposure may be associated with different profiles of symptom frequencies. Knowledge about this may be useful for clinicians and for the movement towards evidence-based personalized psychological treatment.

Subjective judgments on direct and generative retrieval of autobiographical memory: The role of interoceptive sensibility and emotion

Autobiographical remembering is a subjective experience, and whether retrieval is perceived to occur through involuntary or voluntary, direct or generative cognitive processes is also based on subjective intuition. The present study examined factors that may contribute to the subjective judgment that occurs when we perceive memories as being retrieved directly (i.e., a memory comes to mind directly and immediately) or through generative processes (i.e., recalling a memory with effort or by using additional information). We examined the hypothesis that internal awareness (interoceptive sensibility and mindfulness traits) contributes to the physical reaction and emotional impact of memories at retrieval, which then influence the subjective judgment that memories are retrieved directly. In two online experiments, participants were asked to recall specific memories following verbal cues and to judge the retrieval process (i.e., direct or generative). We demonstrated that emotional awareness, an interoceptive sensibility scale factor, consistently predicted a high probability of direct retrieval judgments independent of other predictors of direct retrieval, such as retrieval latency and cue concreteness. This effect was especially common for concrete cues. In Experiment 2 we demonstrated that emotional awareness predicted direct retrieval judgments through the mediation of retrieval impact (physical reaction and emotional impact). These results indicate the involvement of interoceptive processing in the direct retrieval of autobiographical memories. We discuss the role of interoception in memory retrieval and present interoceptive prediction error as a novel and potentially integrative account of our findings.

Trauma and Remembering: From Neuronal Circuits to Molecules

Individuals with posttraumatic stress disorder (PTSD) experience intrusions of vivid traumatic memories, heightened arousal, and display avoidance behavior. Disorders in identity, emotion regulation, and interpersonal relationships are also common. The cornerstone of PTSD is altered learning, memory, and remembering, regulated by a complex neuronal and molecular network. We propose that the essential feature of successful treatment is the modification of engrams in their unstable state during retrieval. During psychedelic psychotherapy, engrams may show a pronounced instability, which enhances modification. In this narrative review, we outline the clinical characteristics of PTSD, its multifaceted neuroanatomy, and the molecular pathways that regulate memory destabilization and reconsolidation. We propose that psychedelics, acting by serotonin-glutamate interactions, destabilize trauma-related engrams and open the door to change them during psychotherapy.

Role of burn severity and posttraumatic stress symptoms in the co-occurrence of itch and neuropathic pain after burns: A longitudinal study

Itch and pain are common after burns. Neuropathic mechanisms may underlie both modalities but remain not well-understood. This study aims to prospectively document neuropathic pain symptoms and to identify potential itch symptom profiles that differ regarding duration and co-occurrence with neuropathic pain which may inform underlying pathophysiological mechanisms and respond to different treatments. Adult burn survivors (n = 192) self-reported itch and neuropathic pain at 2 weeks post-discharge, 3, 6, 12, and 18 months post-burn. Based on the presence of itch and pain symptoms over time, participants were allocated to one itch profile: transient itch/pain, chronic itch, or chronic itch & pain. Profiles were compared on itch intensity over time using General Linear Modeling. Age, gender, burn severity, posttraumatic stress (PTS) symptoms and baseline itch intensity were examined as potential predictors of the profiles in a Multi-nominal regression analysis. Neuropathic pain occurred in 54% after discharge which decreased to 24% 18 months later. Itch intensity was highest in the chronic itch & pain profile. Compared to the transient itch profile, the chronic itch & pain profile was associated with higher burn severity and more PTS symptoms. Compared to the chronic itch profile, the chronic itch & pain profile was associated with more PTS symptoms. Findings suggest that biological and psycho-dermatological processes underlie both chronic neuropathic pain and itch processes in burn scars. Further research should elucidate the mechanisms underlying the different itch profiles, with specific focus on skin innervation and psychological factors.

How childhood maltreatment alters perception and cognition - the predictive processing account of borderline personality disorder

Borderline personality disorder (BPD) is a severe mental disorder, comprised of heterogeneous psychological and neurobiological pathologies. Here, we propose a predictive processing (PP) account of BPD to integrate these seemingly unrelated pathologies. In particular, we argue that the experience of childhood maltreatment, which is highly prevalent in BPD, leaves a developmental legacy with two facets: first, a coarse-grained, alexithymic model of self and others - leading to a rigidity and inflexibility concerning beliefs about self and others. Second, this developmental legacy leads to a loss of confidence or precision afforded beliefs about the consequences of social behavior. This results in an over reliance on sensory evidence and social feedback, with concomitant lability, impulsivity and hypersensitivity. In terms of PP, people with BPD show a distorted belief updating in response to new information with two opposing manifestations: rapid changes in beliefs and a lack of belief updating despite disconfirmatory evidence. This account of distorted information processing has the potential to explain both the instability (of affect, self-image, and interpersonal relationships) and the rigidity (of beliefs about self and others) which is typical of BPD. At the neurobiological level, we propose that enhanced levels of dopamine are associated with the increased integration of negative social feedback, and we also discuss the hypothesis of an impaired inhibitory control of the prefrontal cortex in the processing of negative social information. Our account may provide a new understanding not only of the clinical aspects of BPD, but also a unifying theory of the corresponding neurobiological pathologies. We conclude by outlining some directions for future research on the behavioral, neurobiological, and computational underpinnings of this model, and point to some clinical implications of it.

Is it worth it to personalize the treatment of PTSD? - A variance-ratio meta-analysis and estimation of treatment effect heterogeneity in RCTs of PTSD

Several evidence-based treatments for posttraumatic stress disorder (PTSD) are recommended by international guidelines (e.g., APA, NICE). While their average effects are in general high, non-response rates indicate differential treatment effects. Here, we used a large database of RCTs on psychotherapy for PTSD to determine a reliable estimate of this heterogeneity in treatment effects (HTE) by applying Bayesian variance ratio meta-analysis. In total, 66 studies with a total of 8803 patients were included in our study. HTE was found for all psychological treatments, with varying degrees of certainty, only slight differences between psychological treatments, and active control groups yielding a smaller variance ratio compared to waiting list control groups. Across all psychological treatment and control group types, the estimate for the intercept was 0.12, indicating a 12% higher variance of posttreatment values in the intervention groups after controlling for differences in treatment outcomes. This study is the first to determine the maximum increase in treatment effects of psychological treatments for PTSD by personalization. The results indicate that there is comparatively high heterogeneity in treatment effects across all psychological treatment and control groups, which in turn allow personalizing psychological treatments by using treatment selection approaches.

Testing Bayesian models of belief updating in the context of depressive symptomatology

OBJECTIVES

Predictive processing approaches to belief updating in depression propose that depression is related to more negative and more precise priors. Also, belief updating is assumed be negatively biased in comparison to normative Bayesian updating. There is a lack of efficient methods to mathematically model belief updating in depression.

METHODS

We validated a novel performance belief updating paradigm in a nonclinical sample (N = 133). Participants repeatedly participated in a non-self-related emotion recognition task and received false feedback. Effects of the feedback manipulation and differences in depressive symptoms on belief updating were analysed in Bayesian multilevel analyses.

RESULTS

Beliefs were successfully manipulated through the feedback provided. Depressive symptoms were associated with more negative updating than normative Bayesian updating but results were influenced by few cases. No evidence of biased change in beliefs or overly precise priors was found. Depressive symptoms were associated with more negative updating of generalised performance beliefs.

CONCLUSIONS

There was cautious support for negatively biased belief updating associated with depressive symptoms, especially for generalised beliefs. The content of the task may not be self-relevant enough to cause strong biases. Further explication of Bayesian models of depression and replication in clinical samples is needed.

Oversampled and undersolved: Depressive rumination from an active inference perspective

Rumination is a widely recognized cognitive deviation in depression. Despite the recognition, researchers have struggled to explain why patients cannot disengage from the process, although it depresses their mood and fails to lead to effective problem-solving. We rethink rumination as repetitive but unsuccessful problem-solving attempts. Appealing to an active inference account, we suggest that adaptive problem-solving is based on the generation, evaluation, and performance of candidate policies that increase an organism's knowledge of its environment. We argue that the problem-solving process is distorted during rumination. Specifically, rumination is understood as engaging in excessive yet unsuccessful oversampling of policy candidates that do not resolve uncertainty. Because candidates are sampled from policies that were selected in states resembling one's current state, "bad" starting points (e.g., depressed mood, physical inactivity) make the problem-solving process vulnerable for generating a ruminative "halting problem". This problem leads to high opportunity costs, learned helplessness and diminished overt behavior. Besides reviewing evidence for the conceptual paths of this model, we discuss its neurophysiological correlates and point towards clinical implications.

Can placebos reduce intrusive memories?

After traumatic experiences, intrusive memories can flash back and evoke significant distress. Here, we investigated whether the frequency and severity of intrusions can be reduced by the provision of placebo. After the (online) exposure to the trauma-film paradigm, healthy participants (N = 112) received deceptive placebo (DP), open-label placebo (OLP), or no treatment. In the DP group, participants were led to believe to receive a dopamine-modulating drug, which was supposed to disrupt the consolidation of traumatic memories, although they in fact received the same placebo tablets as the OLP group for one week. The results show that the groups did not differ in the frequency of intrusive memories after one week. However, participants receiving OLP reported a significantly reduced intensity of intrusions as compared to DP. Across groups, negative expectations about the intensity and controllability of intrusions were associated with a higher frequency of intrusions, higher distress, higher burden, and more negative appraisal. The results suggest that expectations play an important role in the emergence of intrusive memories and that some of the disabling aspects of intrusive memories can be reduced by placebo. This may carry clinical potential because placebos are an accessible, cost-effective intervention to reduce the risk of intrusive memories.

A predictive coding account of value-based learning in PTSD: Implications for precision treatments

While there are a number of recommended first-line interventions for posttraumatic stress disorder (PTSD), treatment efficacy has been less than ideal. Generally, PTSD treatment models explain symptom manifestation via associative learning, treating the individual as a passive organism - acted upon - rather than self as agent. At their core, predictive coding (PC) models introduce the fundamental role of self-conceptualisation and hierarchical processing of one's sensory context in safety learning. This theoretical article outlines how predictive coding models of emotion offer a parsimonious framework to explain PTSD treatment response within a value-based decision-making framework. Our model integrates the predictive coding elements of the perceived: self, world and self-in the world and how they impact upon one or more discrete stages of value-based decision-making: (1) mental representation; (2) emotional valuation; (3) action selection and (4) outcome valuation. We discuss treatment and research implications stemming from our hypotheses.

Altered predictive control during memory suppression in PTSD

Aberrant predictions of future threat lead to maladaptive avoidance in individuals with post-traumatic stress disorder (PTSD). How this disruption in prediction influences the control of memory states orchestrated by the dorsolateral prefrontal cortex is unknown. We combined computational modeling and brain connectivity analyses to reveal how individuals exposed and nonexposed to the 2015 Paris terrorist attacks formed and controlled beliefs about future intrusive re-experiencing implemented in the laboratory during a memory suppression task. Exposed individuals with PTSD used beliefs excessively to control hippocampal activity during the task. When this predictive control failed, the prediction-error associated with unwanted intrusions was poorly downregulated by reactive mechanisms. This imbalance was linked to higher severity of avoidance symptoms, but not to general disturbances such as anxiety or negative affect. Conversely, trauma-exposed participants without PTSD and nonexposed individuals were able to optimally balance predictive and reactive control during the memory suppression task. These findings highlight a potential pathological mechanism occurring in individuals with PTSD rooted in the relationship between the brain’s predictive and control mechanisms.

It remains unclear how predictions of future threat affect memory recall, specifically in the case of post-traumatic stress disorder (PTSD). Here, the authors combined computational modeling and brain connectivity analyses to show that individuals with PTSD have exaggerated predictive control and reduced reactive control in a memory suppression task.

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.

Post-traumatic stress disorder is associated with alterations in evoked cortical activation during visual recognition of scenes

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PTSD is associated with impaired performance in the recognition of scene images.

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PTSD is associated with lower activity in frontal, parietal and lateral temporal cortex.

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Difficulties with elaboration on visual cues may lead to impaired recognition in PTSD.

We recorded magnetoencephalography data during a visual recognition task in participants with combat exposure (n = 40, age: 41.2 ± 7.2 years) to investigate the relationship between the evoked brain activity, behavioral performance, and the severity of their post-traumatic stress symptoms assessed using the PTSD Check List for DSM V version (PCL-5). In an initial study session, participants were presented with a series of images of outdoor scenes and were instructed to study the images for an upcoming recognition test. In a subsequent session, the original images were shown intermixed with novel images while participants performed the recognition task. PCL-5 scores were negatively correlated with discrimination performance and with the recognition accuracy for original images. During the recognition session, higher PCL-5 scores were associated with reduced relative power of the evoked response to original images from 100 ms to 300 ms following the image onset over a distributed brain network including the bilateral inferior frontal gyri, left middle frontal gyrus, left supramarginal gyrus, right precuneus and the bilateral superior temporal gyri. These findings indicate that the lower recognition performance in participants with higher PTSD symptom severity is associated with altered cortical activity in brain regions that are known to play a role in the elaboration on visual cues that supports recollection.

Useful misrepresentation: perception as embodied proactive inference

According to the predictive processing framework, perception is geared to represent the environment in terms of embodied action opportunities as opposed to objective truth. Here, we argue that such an optimisation is reflected by biases in expectations (i.e., prior predictive information) that facilitate 'useful' inferences of external sensory causes. To support this, we highlight a body of literature suggesting that perception is systematically biased away from accurate estimates under conditions where utility and accuracy conflict with one another. We interpret this to reflect the brain's attempt to adjudicate between conflicting sources of prediction error, as external accuracy is sacrificed to facilitate actions that proactively avoid physiologically surprising outcomes. This carries important theoretical implications and offers new insights into psychopathology.

Tackling hyperarousal: an integrative multimodal approach

Introduction: The effectiveness of treatment for PTSD is limited, which is especially true for war veterans, of whom 30-50% do not respond to therapy. Hyperarousal is central to the maintenance of trauma pathology. The mainstream trauma-focused therapies traditionally target the cognitive processing of traumatic experience. In this article, we propose that these therapies may be enhanced by the inclusion of interventions specifically targeting hyperarousal.Method: We review an earlier formulated model of trauma supporting our proposal. This model is based on a theory of trauma that integrates the concept of allostasis with the predictive processing framework. In this view, trauma is considered a maladaptive stress response guided by false inference.Results: The reviewed model is in agreement with the central role of hyperarousal in the maintenance of trauma-induced disorders. It also demonstrates the importance of targeting hyperarousal at the same time as maladaptive cognitions and behaviours associated with trauma. A treatment for PTSD is proposed that combines exposure to trauma-related cues with neurofeedback-mediated regulation of arousal.Conclusions: Our analysis argues for the integration of hyperarousal-targeting interventions into existing therapies. Accordingly, we offer methodological considerations based on the nested hierarchy principle that can guide such integration.

Low-level, prediction-based sensory and motor processes are unimpaired in Autism

A new promising account of human brain function suggests that sensory cortices try to optimise information processing via predictions that are based on prior experiences. The brain is thus likened to a probabilistic prediction machine. There has been a growing - though inconsistent - literature to suggest that features of autism spectrum conditions (ASCs) are associated with a deficit in modelling the world through such prediction-based inference. However empirical evidence for differences in low-level sensorimotor predictions in autism is still lacking. One approach to examining predictive processing in the sensorimotor domain is in the context of self-generated (predictable) as opposed to externally-generated (less predictable) effects. We employed two complementary tasks - forcematching and intentional binding - which examine self-versus externally-generated action effects in terms of sensory attenuation and intentional binding respectively in adults with and without autism. The results show that autism was associated with normal levels of sensory attenuation of internally-generated force and with unaltered temporal attraction of voluntary actions and their outcomes. Thus, our results do not support a general deficit in predictive processing in autism.

Neural Computations of Threat

A host of learning, memory, and decision-making processes form the individual's response to threat and may be disrupted in anxiety and post-trauma psychopathology. Here we review the neural computations of threat, from the first encounter with a dangerous situation, through learning, storing, and updating cues that predict it, to making decisions about the optimal course of action. The overview highlights the interconnected nature of these processes and their reliance on shared neural and computational mechanisms. We propose an integrative approach to the study of threat-related processes, in which specific computations are studied across the various stages of threat experience rather than in isolation. This approach can generate new insights about the evolution, diagnosis, and treatment of threat-related psychopathology.

Behavioural Experiments in Cognitive Therapy for Posttraumatic Stress Disorder: Why, When, and How?

Behavioural experiments are an integral component of cognitive therapy (CT) for posttraumatic stress disorder (PTSD), but they can be overlooked due to practical constraints and therapist concerns. Here we describe why behavioural experiments are an important part of CT, where they fit into different elements of treatment for PTSD, how to design and implement effective experiments including coping with unexpected outcomes, and how to incorporate behavioural experiments when therapy is delivered remotely. Clinical case examples are used to illustrate a range of idiosyncratic and creative behavioural experiments.

“Ich denke, also sage ich vorher”: Wie “Predictive Processing-Modelle den Einsatz von Verhaltensexperimenten bei Depressionen optimieren können

Verhaltensexperimente stellen eine wichtige Interventionsform bei depressiven Störungen dar, um dysfunktionale Annahmen zu modifizieren. Häufig ist jedoch zu beobachten, dass Patient*innen trotz einer fachgerechten Durchführung von Verhaltensexperimenten weiter an negativen Annahmen festhalten. Vor diesem Hintergrund diskutieren wir in diesem Artikel, wie der Einsatz von Verhaltensexperimenten bei Depressionen optimiert werden kann und beziehen uns dabei auf ein neues Störungsmodell, das interessante Implikationen hierzu liefern könnte. Dieses Störungsmodell aus der neurowissenschaftlichen Forschung zu “Predictive Processing” geht davon aus, dass depressive Störungen durch zwei Kernaspekte gekennzeichnet sind: (1) stark negative Erwartungen, die im Sinne von selbsterfüllenden Pro­phezeiungen zu negativen Erlebnissen führen und zuneh­mend “immun” gegen gegenteilige Erfahrungen machen; (2) das Fehlen von positiven Erwartungen, wodurch die Wahr­scheinlichkeit von positiven Erlebnissen reduziert wird. Darauf aufbauend beschreiben wir zunächst, dass zur Modifikation negativer Erwartungen in einer ausführlichen Vorbesprechung erarbeitet werden sollte, welche möglichen positiven Erfahrungen aus dem Verhaltensexperiment die Patient*innen als glaubwürdig betrachten und zur Veränderung ihrer negativen Erwartungen nutzen würden. Auf diese sollte bei der Durchführung besonders geachtet werden, damit positive Erwartungsverletzungen auch als solche wahrgenommen werden. Zum anderen stellen wir dar, dass es nicht ausreichend ist, nur negative Erwartungen zu redu­zieren, sondern auch explizit positive Erwartungen durch weitere Verhaltensexperimente gefördert werden sollten.

When Beliefs Face Reality: An Integrative Review of Belief Updating in Mental Health and Illness

Belief updating is a relatively nascent field of research that examines how people adjust their beliefs in light of new evidence. So far, belief updating has been investigated in partly unrelated lines of research from different psychological disciplines. In this article, we aim to integrate these disparate lines of research. After presenting some prominent theoretical frameworks and experimental designs that have been used for the study of belief updating, we review how healthy people and people with mental disorders update their beliefs after receiving new information that supports or challenges their views. Available evidence suggests that both healthy people and people with particular mental disorders are prone to certain biases when updating their beliefs, although the nature of the respective biases varies considerably and depends on several factors. Anomalies in belief updating are discussed in terms of both new insights into the psychopathology of various mental disorders and societal implications, such as irreconcilable political and societal controversies due to the failure to take information into account that disconfirms one’s own view. We conclude by proposing a novel integrative model of belief updating and derive directions for future research.