Expectancy bias and the persistence of posttraumatic stress

Uncertainty cues amplify late positive potential responses to aversive emotional stimuli

Uncertainty is unavoidable, and maladaptive responses to uncertainty may underlie the etiology and maintenance of psychopathology. A general tendency to associate uncertainty with aversive consequences, a type of covariation bias, can amplify aversive emotional experiences. To address questions about uncertainty during emotion regulation, we examined the Late Positive Potential (LPP) - an electrocortical marker of attention to and appraisal of motivationally relevant emotional stimuli - during a task designed to measure the effect of covariation bias and its emotional response consequences. Event-related potentials (ERPs) were recorded while participants (N = 52) were presented with a pre-stimulus cue that either conveyed information about the valence of an upcoming emotional image, or left them in ambiguity. We replicated findings that demonstrate expectancy biases in a priori and online expectancies of emotion-eliciting images, as well as in a posteriori estimates for concurrence of uncertainty cues and aversive images. Moreover, we demonstrate a novel finding that uncertainty cues amplify the LPP in response to subsequent aversive emotional stimuli. These findings advance research by conjoining existing emotion regulation research on the LPP with study of the effects of uncertainty on emotional appraisal and highlight the importance of accounting for stimulus uncertainty in emotion regulation research.

Hypervigilance or shutdown? Electrophysiological processing of trauma-unrelated aversive stimuli after traumatic life events

Post-Traumatic Stress Disorder (PTSD) research indicates that hyper-reactivity to trauma-related stimuli reflects reduced prefrontal cortex (PFC) modulation of amygdala reactivity. However, other studies indicate a dissociative "shutdown" reaction to overwhelming aversive stimuli, possibly reflecting PFC over-modulation. To explore this, we used an Event-Related Potential (ERP) oddball paradigm to study P3 responses in the presence of the following: 1. Trauma-unrelated morbid distractors (e.g., "injured bear") related to the Rorschach inkblot test, and 2. Negative distractors (e.g., "significant failure"), among participants with high post-traumatic stress symptoms (PTS; n = 20), low PTS (n = 17), and controls (n = 15). Distractors were presented at 20% frequency amongst the more frequent (60%) neutral standard stimuli (e.g., "desk lamp") and the equally frequent (20%) neutral trauma-unrelated target stimulus ("golden fish"). P3 amplitudes were high in the presence of morbid distractors and low in the presence of negative distractors only amongst the control group. Possible mechanisms underlying the lack of P3 amplitude modulation after trauma are discussed.

Student reactions to traumatic material in literature: Implications for trigger warnings

INTRODUCTION

While trigger warnings have garnered significant debate, few studies have investigated how students typically respond to potentially triggering material.

METHOD

In this study, three hundred and fifty-five undergraduate students from four universities read a passage describing incidences of both physical and sexual assault. Longitudinal measures of subjective distress, PTSD symptoms, and emotional reactivity were taken.

RESULTS

Greater than 96% of participants read the triggering passage even when given a non-triggering alternative to read. Of those who read the triggering passage, those with triggering traumas did not report more distress although those with higher PTSD scores did. Two weeks later, those with trigger traumas and/or PTSD did not report an increase in trauma symptoms as a result of reading the triggering passage.

CONCLUSIONS

Students with relevant traumas do not avoid triggering material and the effects appear to be brief. Students with PTSD do not report an exacerbation of symptoms two weeks later as a function of reading the passage.

Negative world views after trauma: Neurophysiological evidence for negative expectancies

OBJECTIVE

Negative views of both the self and the world are commonly seen in individuals who have suffered psychological trauma. These negative cognitions are thought to be significant as they are likely to play a critical role in furthering, if not promoting, other symptoms and exacerbating the dysfunction sometimes seen after a traumatic event. This has led to the inclusion of "persistent negative beliefs and expectations about oneself or the world" in the DSM-5 (American Psychiatric Association, 2013). Although there is considerable self-report and behavioral evidence for negative biases after trauma, there is less concurrent neurophysiological data. This study used the N400, an event-related potential sensitive to semantic expectancies, to assess negative expectations in a trauma sample.

METHOD

In this study, 39 participants completed an N400 task in which they read ambiguous sentence stems that ended either with a positive final word (Things will turn out . . . fine) or a negative final word (Things will turn out . . . badly). The authors predicted that those trauma survivors with negative cognitions (as measured by the Posttraumatic Cognitions Inventory [PTCI]: Foa et al., 1999) would show N400 amplitudes indicating expectancies for negative endings. Augmenting the previous self-report data, this would provide evidence for negative expectancies that are fairly early and relatively automatic.

RESULTS

N400 amplitudes to negative sentence endings were significantly related to negative views of the world as measured by the PTCI.

CONCLUSIONS

This suggests that negative world views in trauma survivors have demonstrable neurophysiological correlates and impact on expectations in ambiguous situations. (PsycINFO Database Record

Harm expectancy violation during exposure therapy for posttraumatic stress disorder

Exposure therapy has proven efficacy in the treatment of posttraumatic stress disorder (PTSD). Emotional processing theory proposes that fear habituation is a central mechanism in symptom reduction, but the empirical evidence supporting this is mixed. Recently it has been proposed that violation of harm expectancies is a crucial mechanism of action in exposure therapy. But to date, changes in harm expectancies have not been examined during exposure therapy in PTSD. The goal of the current study was to examine harm expectancy violation as mechanism of change in exposure therapy for posttraumatic stress disorder (PTSD). Patients (N=50, 44 female) with a primary diagnosis of chronic PTSD received intensive exposure therapy. Harm expectancies, harm experiences and subjective units of distress (SUDs) were assessed at each imaginal exposure session, and PTSD symptoms were assessed pre- and posttreatment with the Clinician Administered PTSD Scale (CAPS). Results showed that harm expectancies were violated within and strongly declined in-between exposure therapy sessions. However, expectancy violation was not related to PTSD symptom change. Fear habituation measures were moderately related to PTSD symptom reductions. In line with theory, exposure therapy promotes expectancy violation in PTSD patients, but this is not related to exposure therapy outcome. More work is warranted to investigate mechanisms of change during exposure therapy in PTSD.

Threat expectancy bias and treatment outcome in patients with panic disorder and agoraphobia

BACKGROUND AND OBJECTIVES

Previous studies suggest that patients with panic disorder and agoraphobia (PD/A) tend to overestimate the associations between fear-relevant stimuli and threat. This so-called threat expectancy bias is thought to play a role in the development and treatment of anxiety disorders. The current study tested 1) whether patients with PD/A (N = 71) show increased threat expectancy ratings to fear-relevant and fear-irrelevant stimuli relative to a comparison group without an axis I disorder (N=65), and 2) whether threat expectancy bias before treatment predicts treatment outcome in a subset of these patients (n = 51).

METHODS

In a computerized task, participants saw a series of panic-related and neutral words and rated for each word the likelihood that it would be followed by a loud, aversive sound.

RESULTS

Results showed higher threat expectancy ratings to both panic-related and neutral words in patients with PD/A compared to the comparison group. Threat expectancy ratings did not predict treatment outcome.

LIMITATIONS

This study only used expectancy ratings and did not include physiological measures. Furthermore, no post-treatment expectancy bias task was added to shed further light on the possibility that expectancy bias might be attenuated by treatment.

CONCLUSIONS

Patients show higher expectancies of aversive outcome following both fear-relevant and fear-irrelevant stimuli relative to the comparison group, but this does not predict treatment outcome.

Fear-relevant illusory correlations in different fears and anxiety disorders: A review of the literature

Fearful individuals often overestimate the relationship between fear-relevant stimuli and aversive consequences. Such fear-relevant illusory correlations (ICs) might be involved in the maintenance of anxiety disorders. In this literature review, we found clear evidence that ICs are present and enhanced in fear of animals. We also revealed some evidence for ICs related to fear of flying, social anxiety, contamination fear, panic disorder, and post-traumatic stress disorder, but with considerably less clarity. Fear-relevant ICs seem to be best explained by both a priori expectancies and biased encoding of the experienced associations. Studies to date suggest that one important biased encoding process is the enhanced aversiveness/salience of fear-relevant outcomes. Future studies may improve insight by developing more reliable IC measures and testing the effect of encoding processes on treatment outcomes.

Updated meta-analysis of classical fear conditioning in the anxiety disorders

The aim of the current study was twofold: (1) to systematically examine differences in fear conditioning between anxiety patients and healthy controls using meta-analytic methods, and (2) to examine the extent to which study characteristics may account for the variability in findings across studies. Forty-four studies (published between 1920 and 2013) with data on 963 anxiety disordered patients and 1,222 control subjects were obtained through PubMed and PsycINFO, as well as from a previous meta-analysis on fear conditioning (Lissek et al.). Results demonstrated robustly increased fear responses to conditioned safety cues (CS-) in anxiety patients compared to controls during acquisition. This effect may represent an impaired ability to inhibit fear in the presence of safety cues (CS-) and/or may signify an increased tendency in anxiety disordered patients to generalize fear responses to safe stimuli resembling the conditioned danger cue (CS+). In contrast, during extinction, patients show stronger fear responses to the CS+ and a trend toward increased discrimination learning (differentiation between the CS+ and CS-) compared to controls, indicating delayed and/or reduced extinction of fear in anxiety patients. Finally, none of the included study characteristics, such as the type of fear measure (subjective vs. psychophysiological index of fear), could account significantly for the variance in effect sizes across studies. Further research is needed to investigate the predictive value of fear extinction on treatment outcome, as extinction processes are thought to underlie the beneficial effects of exposure treatment in anxiety disorders.

The experience of traumatic events disrupts the measurement invariance of a posttraumatic stress scale

Studies that include multiple assessments of a particular instrument within the same population are based on the presumption that this instrument measures the same construct over time. But what if the meaning of the construct changes over time due to one's experiences? For example, the experience of a traumatic event can influence one's view of the world, others, and self, and may disrupt the stability of a questionnaire measuring posttraumatic stress symptoms (i.e., it may affect the interpretation of items). Nevertheless, assessments before and after such a traumatic event are crucial to study longitudinal development of posttraumatic stress symptoms. In this study, we examined measurement invariance of posttraumatic stress symptoms in a sample of Dutch soldiers before and after they went on deployment to Afghanistan (N = 249). Results showed that the underlying measurement model before deployment was different from the measurement model after deployment due to invariant item thresholds. These results were replicated in a sample of soldiers deployed to Iraq (N = 305). Since the lack of measurement invariance was due to instability of the majority of the items, it seems reasonable to conclude that the underlying construct of PSS is unstable over time if war-zone related traumatic events occur in between measurements. From a statistical point of view, the scores over time cannot be compared when there is a lack of measurement invariance. The main message of this paper is that researchers working with posttraumatic stress questionnaires in longitudinal studies should not take measurement invariance for granted, but should use pre- and post-symptom scores as different constructs for each time point in the analysis.

Shaking that icky feeling: effects of extinction and counterconditioning on disgust-related evaluative learning

Learned disgust appears to play an important role in certain anxiety disorders, and can be explained by the process of evaluative conditioning, in which an affective evaluative reaction evoked by an unconditional stimulus (US) is transferred to a conditional stimulus (CS). Much remains unknown about how disgust-related evaluative learning can be effectively eliminated. Study 1 of the present investigation examined the effects of extinction on reducing the negative evaluation of a CS that was acquired during disgust conditioning. Participants completed acquisition trials, with a disgusting picture as US and two neutral pictures as CS (CS+ was paired with the US; CS- was unpaired), followed by extinction trials ("CS only"; experimental condition) or a filler task (control condition). Extinction trials reduced acquired US expectancy to the CS+, but did not extinguish negative evaluations of the CS+. Study 2 examined the effects of counterconditioning on evaluative learned disgust. After disgust acquisition trials, counterconditioning trials followed in which the CS+ was paired with a pleasant US (experimental condition) or a filler task (control condition). Counterconditioning trials reduced acquired US expectancy to the CS+ and reduced evaluative conditioned disgust. Implications of the potential differential effects of extinction and counterconditioning on evaluative learning for exposure-based treatment of specific anxiety disorders are discussed.

Impaired fear inhibition learning predicts the persistence of symptoms of posttraumatic stress disorder (PTSD)

Recent cross-sectional studies have shown that the inability to suppress fear under safe conditions is a key problem in people with posttraumatic stress disorder (PTSD). The current longitudinal study examined whether individual differences in fear inhibition predict the persistence of PTSD symptoms. Approximately 2 months after deployment to Afghanistan, 144 trauma-exposed Dutch soldiers were administered a conditional discrimination task (AX+/BX-). In this paradigm, A, B, and X are neutral stimuli. X combined with A is paired with a shock (AX+ trials); X combined with B is not (BX- trials). Fear inhibition was measured (AB trials). Startle electromyogram responses and shock expectancy ratings were recorded. PTSD symptoms were measured at 2 months and at 9 months after deployment. Results showed that greater startle responses during AB trials in individuals who discriminated between danger (AX+) and safety (BX-) during conditioning, predicted higher PTSD symptoms at 2 months and 9 months post-deployment. The predictive effect at 9 months remained significant after controlling for critical incidents during previous deployments and PTSD symptoms at 2 months. Responses to AX+ or BX- trials, or discrimination learning (AX+ minus BX-) did not predict PTSD symptoms. It is concluded that impaired fear inhibition learning seems to be involved in the persistence of PTSD symptoms.

Contributors to hypervigilance in a military and civilian sample

Hypervigilance toward ambiguous or threatening stimuli is a prominent feature in many trauma survivors including active and returning soldiers. This study set out to investigate the factors that contribute to hypervigilance in a mixed sample. One hundred forty-five individuals, 50 of whom were war zone veterans, filled out a series of questionnaires including the Hypervigilance Questionnaire (HVQ; Kimble, Fleming, & Bennion, 2009). Other participants included military cadets, college undergraduates, and a traumatized community sample. In this sample, a history of military deployment and posttraumatic stress disorder symptoms independently predicted hypervigilance. The findings suggest that deployment to a war zone, in and of itself, can lead to hypervigilant behavior. Therefore, characterizing hypervigilance as pathological in a veteran sample must be done so with caution.

Negative expectancies in posttraumatic stress disorder: neurophysiological (N400) and behavioral evidence

BACKGROUND

Posttraumatic stress disorder (PTSD) is a disorder that theoretically and clinically is thought to be associated with persistent and exaggerated negative expectancies. This study used the N400 event-related potential (ERP) to investigate expectancies for threatening endings to ambiguous sentence stems. The N400 ERP is thought to reflect the amount of effort required to integrate a stimulus into a given context. In sentence reading tasks, the N400 is reliably larger when a word is unexpected.

METHOD

In this study, fifty-seven trauma survivors of various types (22 with PTSD and 35 without) read ambiguous sentence stems on a computer screen. These sentence stems were completed with either an expected ("The unfortunate man lost his…wallet"), unexpected ("The unfortunate man lost his…artist"), or threatening word endings ("The unfortunate man lost his…leg").

RESULTS

Participants with PTSD, as compared to those without, showed significantly smaller N400s to threatening sentence endings suggesting enhanced expectancies for threat. Behavioral responses supported this conclusion.

CONCLUSIONS

These findings are consistent with the clinical presentation of hypervigilance and proposed revisions to the DSM-V that emphasize persistent and exaggerated negative expectations about one's self, others, or the world. Relative to earlier behavioral studies, this work further suggests that this expectancy bias occurs automatically and at the early stages of information processing. The discussion focuses on the potential impact of a negative expectancy bias in PTSD and the value of the ambiguous sentence paradigm for studying PTSD as well as other disorders.

Uncertainty is associated with biased expectancies and heightened responses to aversion

Uncertainty is an omnipresent force in peoples' lives that has been shown to amplify the negative impact of aversive events. This amplified aversiveness, together with the negative attitudes that individuals can have toward uncertainty, suggests that a cue indicating uncertainty about future events might be associated with biased expectancies of negative outcomes or biased contingency estimates, similar to biases that have been observed for traditional fear-relevant cues, such as snakes or spiders. Participants in this study saw three different cues: one that indicated with certainty that an aversive picture would follow, one that indicated with certainty that a neutral picture would follow, and one that indicated uncertainty about whether an aversive or neutral picture would follow. Online self-report data revealed negatively biased expectancies of aversion after uncertain cues. The degree of this online expectancy bias predicted participants' estimates, at the conclusion of the experiment, of the relationship between uncertain cues and aversive pictures. Aversive pictures after the uncertain cue (relative to those after the certain cue) were accompanied by increased skin conductance responses and self-reported negative mood. These findings that uncertainty is accompanied by biased expectancies of aversion and heightened responses to aversion warrant extensions of this research in anxiety disorders, given evidence for intolerance of uncertainty and anticipatory dysfunction in the pathology of such disorders.

Disgust and the development of posttraumatic stress among soldiers deployed to Afghanistan

Although the DSM-IV recognizes that events can traumatize by evoking horror, not just fear, the role of disgust in the development of posttraumatic stress disorder (PTSD) has received little research attention. In a study of soldiers deployed to Afghanistan, we examined whether reports of peritraumatic disgust and trait disgust vulnerability factors (disgust propensity and disgust sensitivity) predict PTSD-symptoms, independently of peritraumatic fear, neuroticism, and anxiety sensitivity. Participants (N = 174) enrolled in this study before deployment, and were retested around 6 months (N = 138; 79%) and, again, 15 months (N = 107; 62%) after returning home. The results showed that (1) greater peritraumatic disgust and fear independently predicted PTSD-symptom severity at 6 months, (2) greater disgust propensity predicted more peritraumatic disgust, but not PTSD-symptom severity, and (3) disgust sensitivity moderated the relationship between peritraumatic disgust and PTSD-symptom severity. Implications of these findings for broadening the affective vulnerabilities that may contribute to PTSD will be discussed.