Prospective prediction of posttraumatic stress disorder symptoms using fear potentiated auditory startle responses

Fear generalization predicts post-traumatic stress symptoms: A two-year follow-up study in Dutch fire fighters

INTRODUCTION

Excessive fear generalization has been associated with pathological anxiety, including posttraumatic stress disorder (PTSD). However, studies investigating the longitudinal relationship between generalization and the development of anxiety symptomatology are scarce. This study aims to test the predictive value of fear generalization for PTSD symptoms in a high-risk profession sample and to explore the relationship between generalization and neuroticism, which are both linked to PTSD.

METHOD

Longitudinal data from a multi-wave study in 529 Dutch fire-fighters were used. Fear generalization, PTSD symptoms and neuroticism were assessed at baseline. PTSD symptoms were reevaluated at six, 12, 18, and 24 months. Generalization was assessed in a differential conditioning paradigm by measuring expectancies of an aversive outcome when presented with stimuli similar to previously conditioned stimuli.

RESULTS

Higher expectancy ratings towards stimuli most similar to safety signals predicted PTSD symptoms at follow-up after controlling for baseline PTSD symptoms, whereas higher expectancy ratings towards stimuli most similar to danger signals was associated with neuroticism. Neuroticism weakened the predictive power of fear generalization when considered simultaneously.

DISCUSSION

These findings suggest that heightened fear generalization is associated with the development of anxiety and trauma-related symptoms. Targeting problematic fear generalization may be a promising intervention approach.

Context as a barrier: Impaired contextual processing increases the tendency to develop PTSD symptoms across repeated exposure to trauma

Growing evidence links repeated traumatic exposure with impaired ability to process contextual information. Specifically, like individuals with PTSD, non-PTSD trauma-exposed individuals fail to react according to contextual demands. In the present study, we explored the process that underlies this impairment. First, we tested the ability of first responders to benefit from contextual primes to improve recognition. Second, we assessed its moderating role in the relationship between traumatic exposure and PTSD symptoms. Fifty-three active-duty firefighters and 33 unexposed civilians matched for age, gender, and years of education participated in the study. All participants completed the contextual priming paradigm, the CAPS-5 clinical interview, and the WAIS-IV vocabulary subtest and were assessed for depression and general traumatic exposure. Repeated traumatic exposure was assessed objectively using the fire-and-rescue-service tracking system. As predicted, we found that trauma-exposed individuals failed to use primes to facilitate rapid and accurate recognition of contextually related objects. Not only did contextual information not improve performance, but it achieved the opposite effect, manifested as negative priming. Hence, context appeared to be an obstacle for trauma-exposed individuals and delayed rapid and accurate recognition. Moreover, impaired ability to process contextual information predicted the tendency to develop PTSD symptoms across repeated exposure to trauma.

Watching with Argus eyes: Characterization of emotional and physiological responding in adults exposed to childhood maltreatment and/or recent adversity

Exposure to adverse experiences is a well-established major risk factor for affective psychopathology. The vulnerability of deleterious sequelae is assumed in maladaptive processes of the defensive system, particularly in emotional processing. More specifically, childhood maltreatment has been suggested to be associated with the recruitment of specific and distinct defensive response profiles. To date, it remains unclear whether these are specific or generalizable to recent adversity in adulthood. This pre-registered study aimed to investigate the impact of exposure to childhood and recent adversity on emotional processing in 685 healthy adults with the "Affective Startle Modulation" Paradigm (ASM). First, we replicated higher trait anxiety and depression levels in individuals exposed to both types of adversity. Second, we observed increased general skin conductance reactivity in individuals exposed to recent adversity. Third, individuals exposed to childhood maltreatment showed reduced, while individuals exposed to recent adversity showed increased discrimination between pictures of negative and neutral valence, compared with non-exposed individuals in SCR. No association between exposure to adversity and fear potentiated startle was observed. Furthermore, explorative analyses revealed moderate dimensional and categorical agreement between two childhood maltreatment questionnaires and provide insight into potential adversity-type specific effects. Our results support experience-dependent plasticity in sympathetic nervous system reactivity and suggest distinct response profiles in affective modulation in individuals exposed to early versus recent adversity. We emphasize the need to further explore distinct adversity profiles to further our understanding on specific psychophysiological profiles and their potential implication for prevention and intervention.

Toward staging differentiation for posttraumatic stress disorder treatment

OBJECTIVES

Several medical and psychiatric disorders have stage-based treatment decision-making methods. However, international treatment guidelines for posttraumatic stress disorder (PTSD) fail to give specific treatment recommendations based on chronicity or stage of the disorder. There is convincing evidence of a finite range of PTSD symptom trajectories, implying that different phenotypes of the disorder can be distinguished, which are highly relevant for a staging typology of PTSD.

METHODS

State-of-the-art review building on prior work on staging models in other disorders as a mapping tool to identify and synthesize toward PTSD.

RESULTS

We propose a four-stage model of PTSD ranging from stage 0: trauma-exposed asymptomatic but at risk to stage 4: severe unremitting illness of increasing chronicity. We favor a symptom description in various chronological characteristics based on neurobiological markers, information processing systems, stress reactivity, and consciousness dimensions. We also advocate for a separate phenomenology of treatment resistance since this can yield treatment recommendations.

CONCLUSION

A staging perspective in the field of PTSD is highly needed. This can facilitate the selection of interventions that are proportionate to patients' current needs and risk of illness progression and can also contribute to an efficient framework to organize biomarker data and guide service delivery. Therefore, we propose that a neurobiologically driven trajectory-based typology of PTSD can help deduct several treatment recommendations leading to a more personalized and refined grid to strategize, plan and evaluate treatment interventions.

Involvement of the GABAergic system in PTSD and its therapeutic significance

The neurobiological mechanism of post-traumatic stress disorder (PTSD) is poorly understood. The inhibition of GABA neurons, especially in the amygdala, is crucial for the precise regulation of the consolidation, expression, and extinction of fear conditioning. The GABAergic system is involved in the pathophysiological process of PTSD, with several studies demonstrating that the function of the GABAergic system decreases in PTSD patients. This paper reviews the preclinical and clinical studies, neuroimaging techniques, and pharmacological studies of the GABAergic system in PTSD and summarizes the role of the GABAergic system in PTSD. Understanding the role of the GABAergic system in PTSD and searching for new drug targets will be helpful in the treatment of PTSD.

Threat Responsivity Predicts Posttraumatic Stress Disorder Hyperarousal Symptoms in Children after Hurricane Florence

Following a traumatic event, posttraumatic stress disorder (PTSD) symptoms are common. Considerable research has identified a relationship between physiological responses during fear learning and PTSD. Adults with PTSD display atypical physiological responses, such as increased skin conductance responses (SCR) to threatening cues during fear learning (Orr et al., 2000). However, little research has examined these responses in childhood when fear learning first emerges. We hypothesized that greater threat responsivity in early acquisition during fear conditioning before Hurricane Florence would predict PTSD symptoms in a sample of young children following the hurricane. The final sample included 58 children in North Carolina who completed fear learning before Hurricane Florence-a potentially traumatic event. After the hurricane, we assessed severity of hurricane impact and PTSD symptoms. We found that threat responsivity as measured by differential SCR during fear learning before the hurricane predicted PTSD hyperarousal symptoms and that hurricane impact predicted PTSD symptoms following the disaster. This exploratory work suggests that prospective associations between threat responsivity and PTSD symptoms observed in adulthood may be replicated in early childhood. Results are discussed in the context of the current COVID-19 crisis.

Effects of oxytocin administration on fear-potentiated acoustic startle in co-occurring PTSD and alcohol use disorder: A randomized clinical trial

Co-occurring posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) is common and particularly associated with elevation of hyperarousal compared to PTSD alone. Treatment options are limited. Oxytocin regulates physiological stress response. Intranasal oxytocin administration has demonstrated potential in reducing symptoms of both PTSD and AUD. This study addresses a gap in the literature by investigating effects of intranasal oxytocin on startle reactivity, an important potential marker of both PTSD and AUD symptomatology. This is a randomized, double-blind, placebo-controlled, within- and between-participant, crossover, dose-ranging study examining the effects of a single administration of oxytocin 20 IU versus 40 IU versus placebo on psychophysiological responses to a common laboratory fear-potentiated acoustic startle paradigm in participants with PTSD-AUD (n = 47) and controls (n = 37) under three different levels of threat. Contrary to our hypothesis, for the PTSD-AUD group, oxytocin 20 IU had no effect on startle reactivity, while oxytocin 40 IU increased measures of startle reactivity. Additionally, for PTSD-AUD only, ambiguous versus low threat was associated with an elevated skin conductance response. For controls only, oxytocin 20 IU versus placebo was associated with reduced startle reactivity.

Neural and Self-report Measures of Sensitivity to Uncertainty as Predictors of COVID-Related Negative Affect

The COVID-19 pandemic has been a period of unprecedented uncertainty. Research indicates individuals differ in their response to uncertainty and these differences are mediated by anterior insula (aINS) function. Those most sensitive to uncertainty are likely vulnerable to negative affect in the context of the pandemic. The current study was designed to directly test this question using both neural and self-reported measures of sensitivity to uncertainty. Fifty-nine volunteers completed a task designed to probe neural response to anticipation of predictable (P-) and unpredictable (U-) threat-of-electric-shock during functional magnetic resonance imaging and a self-report measure of intolerance of uncertainty (IU). Approximately two years later, during the peak of the pandemic, participants reported their emotional reactions to the COVID-19 crisis. Multilevel mixed models revealed that greater aINS activation to U-threat and greater self-reported IU were independent predictors of increased COVID-related negative affect. These findings were significant when adjusting for biological sex and depression and anxiety symptom severity. The results add to a growing literature demonstrating that individual differences in response to uncertainty have a robust impact on mood and functioning. Results also highlight that individuals highly sensitive to uncertainty may be at increased risk for poor mental health during the ongoing pandemic.

AI-Based Prediction and Prevention of Psychological and Behavioral Changes in Ex-COVID-19 Patients

The COVID-19 pandemic has adverse consequences on human psychology and behavior long after initial recovery from the virus. These COVID-19 health sequelae, if undetected and left untreated, may lead to more enduring mental health problems, and put vulnerable individuals at risk of developing more serious psychopathologies. Therefore, an early distinction of such vulnerable individuals from those who are more resilient is important to undertake timely preventive interventions. The main aim of this article is to present a comprehensive multimodal conceptual approach for addressing these potential psychological and behavioral mental health changes using state-of-the-art tools and means of artificial intelligence (AI). Mental health COVID-19 recovery programs at post-COVID clinics based on AI prediction and prevention strategies may significantly improve the global mental health of ex-COVID-19 patients. Most COVID-19 recovery programs currently involve specialists such as pulmonologists, cardiologists, and neurologists, but there is a lack of psychiatrist care. The focus of this article is on new tools which can enhance the current limited psychiatrist resources and capabilities in coping with the upcoming challenges related to widespread mental health disorders. Patients affected by COVID-19 are more vulnerable to psychological and behavioral changes than non-COVID populations and therefore they deserve careful clinical psychological screening in post-COVID clinics. However, despite significant advances in research, the pace of progress in prevention of psychiatric disorders in these patients is still insufficient. Current approaches for the diagnosis of psychiatric disorders largely rely on clinical rating scales, as well as self-rating questionnaires that are inadequate for comprehensive assessment of ex-COVID-19 patients' susceptibility to mental health deterioration. These limitations can presumably be overcome by applying state-of-the-art AI-based tools in diagnosis, prevention, and treatment of psychiatric disorders in acute phase of disease to prevent more chronic psychiatric consequences.

Dissociable impact of childhood trauma and deployment trauma on affective modulation of startle

Trauma disorders are often associated with alterations in aversive anticipation and disruptions in emotion/fear circuits. Heightened or blunted anticipatory responding to negative cues in adulthood may be due to differential trauma exposure during development, and previous trauma exposure in childhood may also modify effects of subsequent trauma in adulthood. The aim of the current investigation was to examine the contributions of childhood trauma on affective modulation of startle before and after trauma exposure in adulthood (a combat deployment). Adult male participants from the Marine Resilience Study with (n = 1145) and without (n = 1312) a history of reported childhood trauma completed an affective modulation of startle task to assess aversive anticipation. Affective startle response was operationalized by electromyography (EMG) recording of the orbicularis oculi muscle in response to acoustic stimuli when anticipating positive and negative affective images. Startle responses to affective images were also assessed. Testing occurred over three time-points; before going on a 7 month combat deployment and 3 and 6 months after returning from deployment. Startle response when anticipating negative images was greater compared to pleasant images across all three test periods. Across all 3 time points, childhood trauma was consistently associated with significantly blunted startle when anticipating negative images, suggesting reliable effects of childhood trauma on aversive anticipation. Conversely, deployment trauma was associated with increased startle reactivity post-deployment compared to pre-deployment, which was independent of childhood trauma and image valence. These results support the hypothesis that trauma exposure during development vs. adulthood may have dissociable effects on aversive anticipation and arousal mechanisms. Further study in women and across more refined age groups is needed to test generalizability and identify potential developmental windows for these differential effects.

The novel vasopressin receptor (V1aR) antagonist SRX246 reduces anxiety in an experimental model in humans: a randomized proof-of-concept study

RATIONALE

Arginine vasopressin (AVP) is a neuropeptide that modulates both physiological and emotional responses to threat. Until recently, drugs that target vasopressin receptors (V1a) in the human central nervous system were unavailable. The development of a novel V1a receptor antagonist, SRX246, permits the experimental validation of vasopressin's role in the regulation of anxiety and fear in humans.

OBJECTIVES

Here, we examined the effects of SRX246 in a proof-of-concept translational paradigm of fear (phasic response to imminent threat) and anxiety (prolonged response to potential threat).

METHODS

Healthy volunteers received both SRX246 and placebo in a randomized, double-blind, counter-balanced order separated by a 5-7-day wash-out period. Threat consisted of unpleasant electric shocks. The "NPU" threat test probed startle reactivity during predictable threat (i.e., fear-potentiated startle) and unpredictable threat (i.e., anxiety-potentiated startle).

RESULTS

As predicted, SRX246 decreased anxiety-potentiated startle independent of fear-potentiated startle.

CONCLUSIONS

As anxiety-potentiated startle is elevated in anxiety and trauma-associated disorders and decreased by traditional anxiolytics such as SSRIs and benzodiazepines, the V1a receptor is a promising novel treatment target.

Predisposing Variations in Fear-Related Brain Networks Prospectively Predict Fearful Feelings during the 2019 Coronavirus (COVID-19) Pandemic

The novel coronavirus (COVID-19) pandemic has led to a surge in mental distress and fear-related disorders, including posttraumatic stress disorder (PTSD). Fear-related disorders are characterized by dysregulations in fear and the associated neural pathways. In the present study, we examined whether individual variations in the fear neural connectome can predict fear-related symptoms during the COVID-19 pandemic. Using machine learning algorithms and back-propagation artificial neural network (BP-ANN) deep learning algorithms, we demonstrated that the intrinsic neural connectome before the COVID-19 pandemic could predict who would develop high fear-related symptoms at the peak of the COVID-19 pandemic in China (Accuracy rate = 75.00%, Sensitivity rate = 65.83%, Specificity rate = 84.17%). More importantly, prediction models could accurately predict the level of fear-related symptoms during the COVID-19 pandemic by using the prepandemic connectome state, in which the functional connectivity of lvmPFC (left ventromedial prefrontal cortex)-rdlPFC (right dorsolateral), rdACC (right dorsal anterior cingulate cortex)-left insula, lAMY (left amygdala)-lHip (left hippocampus) and lAMY-lsgACC (left subgenual cingulate cortex) was contributed to the robust prediction. The current study capitalized on prepandemic data of the neural connectome of fear to predict participants who would develop high fear-related symptoms in COVID-19 pandemic, suggesting that individual variations in the intrinsic organization of the fear circuits represent a neurofunctional marker that renders subjects vulnerable to experience high levels of fear during the COVID-19 pandemic.

Behavioral Expression of Contextual Fear in Male and Female Rats

The study of fear conditioning has led to a better understanding of fear and anxiety-based disorders such as post-traumatic stress disorder (PTSD). Despite the fact many of these disorders are more common in women than in men, the vast majority of work investigating fear conditioning in rodents has been conducted in males. The goal of the work presented here was to better understand how biological sex affects contextual fear conditioning and expression. To this end, rats of both sexes were trained to fear a specific context and fear responses were measured upon re-exposure to the conditioning context. In the first experiment, male and female rats were given context fear conditioning and tested the next day during which freezing behavior was measured. In the second experiment, rats were trained and tested in a similar fashion while fear-potentiated startle and defecation were measured. We found that males showed more freezing behavior than females during a fear expression test. The expression of fear-potentiated startle did not differ between sexes, while males exhibited more defecation during a test in a novel context. These data suggest that the expression of defensive behavior differs between sexes and highlight the importance of using multiple measures of fear when comparing between sexes.

Changes in intolerance of uncertainty over the course of treatment predict posttraumatic stress disorder symptoms in an inpatient sample

Intolerance of uncertainty (IU) is the inability to tolerate distress that arises in response to the absence of important information. The level of IU has been investigated across various psychological disorders; however, few studies have examined IU in trauma‐affected samples. We aimed to investigate the relationship between IU and posttraumatic stress disorder (PTSD) across the course of treatment. Participants (n = 106) had a diagnosis of PTSD and were from first responder, military, and occupational injury backgrounds. Participants completed self‐report questionnaires pre‐ and post‐engagement in an inpatient group trauma‐informed psychoeducation and skills (TIPS) intervention. Regression analyses indicated that decreases in overall and inhibitory IU were associated with decreases in PTSD severity overall and at the symptom cluster level. However, prospective IU was only associated with changes in the re‐experiencing, avoidance, and arousal PTSD symptom clusters. Our findings are congruent with the nascent literature indicating that IU may be a maintaining factor for PTSD, suggesting clinical relevance for attendance to IU within the course of treatment.

Prediction of Task Performance From Physiological Features of Stress Resilience

In this paper, we investigate the potential of generic physiological features of stress resilience in predicting air traffic control (ATC) candidates' performance in a highly-stressful low-fidelity ATC simulator scenario. Stress resilience is highlighted as an important occupational factor that influences the performance and well-being of air traffic control officers (ATCO). Poor stress management, besides the lack of skills, can be a direct cause of poor performance under stress, both in the selection process of ATCOs and later in the workplace. 40 ATC candidates, within the final stages of their selection process, underwent a stimulation paradigm for elicitation and assessment of various generic task-unrelated physiological features, related to resting heart rate variability (HRV) and respiratory sinus arrhythmia (RSA), acoustic startle response (ASR) and the physiological allostatic response, which are all recognized as relevant psychophysiological markers of stress resilience. The multimodal approach included analysis of electrocardiography, electromyography, electrodermal activity and respiration. We make advances in computational methodology for assessment of physiological features of stress resilience, and investigate the predictive power of the obtained feature space in a binary classification problem: prediction of high- vs. low-performance on the developed ATC simulator. Our novel approach yields a relatively high 78.16% classification accuracy. These results are discussed in the context of prior work, while considering study limitations and proposing directions for future work.

Reexamination of diathesis stress and neurotoxic stress theories: A qualitative review of pre-trauma neurobiology in relation to posttraumatic stress symptoms

OBJECTIVE

Associations of neurobiological differences with posttraumatic stress disorder (PTSD) have generated interest in their temporal relation. Support has been voiced for the neurotoxic stress theory (NST) in which neurobiological differences develop following exposure and PTSD development. In contrast, the diathesis stress theory (DST) posits that neurobiological differences existed prior to exposure and may be vulnerability factors for PTSD. Studies in the first wave of neurobiological PTSD research were all cross sectional, but a second wave of research followed which used prospective repeated-measures designs that measured neurobiology prior to trauma exposure experiences, allowing greater causal inference.

METHODS

This study reviewed the second-wave studies in hopes of developing a preliminary consensus to support either the NST or the DST based on this more powerful prospective, repeated-measures study design.

RESULTS

Twenty-five second-wave studies were located that measured neurobiology prior to traumatic experiences. Nineteen studies supported the DST. Of 10 studies that were capable of testing the NST, only 3 were supportive.

CONCLUSION

The implications of the NST versus the DST have profound implications for understanding the fragility of the human brain and possible paths forward for future research on assessment, treatment, and social policy.

Heart Rate Reactivity to Acute Psychological Stress Predicts Higher Levels of Posttraumatic Stress Disorder Symptoms During the COVID-19 Pandemic

OBJECTIVE

Increased autonomic arousal is a proposed risk factor for posttraumatic stress disorder (PTSD). Few studies have prospectively examined the association between physiological responses to acute psychological stress before a traumatic event and later PTSD symptoms. The present prospective study examined whether cardiovascular responses to an acute psychological stress task before the COVID-19 global pandemic predicted PTSD symptoms related to the ongoing pandemic.

METHODS

Participants (n = 120) were a subsample of an ongoing research study. Phase 1 consisted of a 10-minute baseline and 4-minute acute psychological stress task with blood pressure and heart rate recorded throughout. Phase 2 was initiated 2 weeks after the COVID-19 pandemic declaration. Participants completed the Impact of Event Scale-Revised (IES-R) with respect to the ongoing pandemic. Hierarchical linear regression analyses were used to examine whether cardiovascular stress reactivity predicted COVID-19 PTSD symptoms.

RESULTS

Heart rate reactivity significantly predicted IES intrusion (β = -0.208, t = -2.28, p = .025, ΔR2 = 0.041, confidence interval = -0.021 to -0.001) and IES hyperarousal (β = -0.224, t = -2.54, p = .012, ΔR2 = 0.047, confidence interval = -0.22 to - 0.003), but not IES avoidance (p = .077). These results remained statistically significant after adjustment for sex, socioeconomic status, baseline cardiovascular activity, neuroticism, race, ethnicity, body mass index, and adverse childhood experiences. There were no statistically significant associations between blood pressure and any of the Impact of Event Scale-Revised subscales (p values > .12).

CONCLUSIONS

Diminished heart rate responses (i.e., lower physiological arousal) to acute psychological stress before the COVID-19 pandemic significantly predicted reported PTSD symptoms during the crisis.

Developmental stress has sex-specific effects on contextual and cued fear conditioning in adulthood

Stress-induced deviations in central nervous system development has long-term effects on adult mental health. Previous research in humans demonstrates that prenatal or adolescent stress increases the risk for psychiatric disorders. Animal models investigating the effects of stress during prenatal or adolescent development produces behavioral outcomes analogous to those observed in humans. However, whether adolescent stress exposure potentiates the effects of prenatal stress is currently unknown. Thus, the current study tested whether adolescent stress increases the impact of prenatal stress on contextual and cued fear memory in adulthood. Male and female Sprague Dawley rats were exposed to a chronic variable stress schedule during the last week of gestation, during adolescence, or during both developmental periods before undergoing fear conditioning training in adulthood. Our hypothesis predicted that the combined effects of prenatal and adolescent stress on contextual and cued fear memory would be greater than the effects of stress during either time period alone. In contrast to our hypothesis, however, we found independent effects of prenatal and adolescent stress on contextual and cued fear memory in both sexes, with no additional combined impact of stress exposure during both developmental phases. In males, developmental stress increased freezing behavior during contextual and cued testing regardless of whether stress exposure was prenatal, adolescent, or combined prenatal and adolescent stress exposure. In contrast, the effects of developmental stress in females were both test- and ovarian hormone status-dependent. During cued testing, nonstressed female freezing behavior depended on estrous cycle phase, whereas freezing behavior in stressed females did not, suggesting that developmental stress interferes with hormone-dependent cued fear memory. No effects of developmental stress or estrous cycle phase were observed for contextual fear memory in females. The results of the current study suggest that the effects of prenatal and adolescent stress on contextual and cued fear memory are not cumulative, but the effects of developmental stress on associative memory differ between males and females.

Prospective risk and protective factors for psychopathology and wellbeing in civilian emergency services personnel: a systematic review

Emergency services personnel have an elevated risk of developing mental health conditions. Most research in this area is cross-sectional, which precludes inferences about temporal and potentially causal relationships between risk and protective factors and mental health outcomes. The current study systematically reviewed prospective studies of risk and protective factors for mental health outcomes in civilian emergency services personnel (firefighters, paramedics, police) assessed at pre-operational and operational stages. Out of 66 eligible prospective studies identified, several core groups of risk and protective factors emerged: (1) cognitive abilities; (2) coping tendencies; (3) personality factors; (4) peritraumatic reactions and post-trauma symptoms; (5) workplace factors; (6) interpersonal factors; (7) events away from work. Although there was insufficient evidence for many associations, social support was consistently found to protect against the development of mental health conditions, and peritraumatic dissociation, prior mental health issues, and prior trauma exposure were risk factors for future mental health conditions. Among operational studies, neuroticism was significantly associated with future PTSD symptoms, burnout, and general poor mental health, and avoidance and intrusion symptoms of PTSD were associated with future PTSD and depression symptoms. The current review results provide important targets for future research and interventions designed to improve the mental health of emergency services personnel.

Neurobehavioral correlates of impaired emotion recognition in pediatric PTSD

Despite broad evidence suggesting that adversity-exposed youth experience an impaired ability to recognize emotion in others, the underlying biological mechanisms remains elusive. This study uses a multimethod approach to target the neurological substrates of this phenomenon in a well-phenotyped sample of youth meeting diagnostic criteria for posttraumatic stress disorder (PTSD). Twenty-one PTSD-afflicted youth and 23 typically developing (TD) controls completed clinical interview schedules, an emotion recognition task with eye-tracking, and an implicit emotion processing task during functional magnetic resonance imaging )fMRI). PTSD was associated with decreased accuracy in identification of angry, disgust, and neutral faces as compared to TD youth. Of note, these impairments occurred despite the normal deployment of visual attention in youth with PTSD relative to TD youth. Correlation with a related fMRI task revealed a group by accuracy interaction for amygdala-hippocampus functional connectivity (FC) for angry expressions, where TD youth showed a positive relationship between anger accuracy and amygdala-hippocampus FC; this relationship was reversed in youth with PTSD. These findings are a novel characterization of impaired threat recognition within a well-phenotyped population of severe pediatric PTSD. Further, the differential amygdala-hippocampus FC identified in youth with PTSD may imply aberrant efficiency of emotional contextualization circuits.

Unconditioned response to an aversive stimulus as predictor of response to conditioned fear and safety: A cross-species study

Safety signals predict the non-occurrence of an aversive event, thereby inhibiting fear responses. Previous research has shown that conditioned safety learning is impaired in patients suffering from post-traumatic stress disorder (PTSD). Using a translational approach, the present study aimed to investigate whether individual responses to an aversive unconditioned stimulus (US) in rats (basic science), non-traumatized (pre-clinical) or traumatized humans (clinical) predicts their response to a conditioned fear or safety stimulus. Using three different archival datasets, the unconditioned response (UCR) to the US during fear or safety conditioning was assessed in rats, non-traumatized humans, and trauma-exposed humans. The response to learned fear (CS+; context) and safety (CS-) was measured by the modulation of the startle response (rats, traumatized humans) or skin conductance response (non-traumatized humans). Our results showed that all groups with low UCR and those with high UCR from the rodent or non-traumatized human samples displayed lower fear response to the CS- than to the CS+ . Traumatized humans with high UCR showed similarly high responses to the CS+ and CS-. While all groups showed a positive association between the UCR and CS+ response, the UCR correlated positively with the CS- response in traumatized humans only. Our findings suggest that an elevated response to aversive stimuli predicts deficits in conditioned safety memory in those at risk for trauma-related disorders and confirms that impaired safety learning could be a valid biomarker for these diseases.

Extinction Learning as a Potential Mechanism Linking High Vagal Tone with Lower PTSD Symptoms among Abused Youth

Childhood abuse is a potent risk factor for psychopathology, including posttraumatic stress disorder (PTSD). Research has shown high resting vagal tone, a measure of parasympathetic nervous system function, protects abused youth from developing internalizing psychopathology, but potential mechanisms explaining this effect are unknown. We explored fear extinction learning as a possible mechanism underlying the protective effect of vagal tone on PTSD symptoms among abused youth. We measured resting respiratory sinus arrhythmia (RSA) and skin conductance responses (SCR) during a fear conditioning and extinction task in youth with variability in abuse exposure (N = 94; aged 6-18 years). High RSA predicted lower PTSD symptoms and enhanced extinction learning among abused youths. In a moderated-mediation model, extinction learning mediated the association of abuse with PTSD symptoms only among youth with high RSA. These findings highlight extinction learning as a possible mechanism linking high vagal tone to decreased risk for PTSD symptoms among abused youth.

Computational causal discovery for post-traumatic stress in police officers

This article reports on a study aimed to elucidate the complex etiology of post-traumatic stress (PTS) in a longitudinal cohort of police officers, by applying rigorous computational causal discovery (CCD) methods with observational data. An existing observational data set was used, which comprised a sample of 207 police officers who were recruited upon entry to police academy training. Participants were evaluated on a comprehensive set of clinical, self-report, genetic, neuroendocrine and physiological measures at baseline during academy training and then were re-evaluated at 12 months after training was completed. A data-processing pipeline-the Protocol for Computational Causal Discovery in Psychiatry (PCCDP)-was applied to this data set to determine a causal model for PTS severity. A causal model of 146 variables and 345 bivariate relations was discovered. This model revealed 5 direct causes and 83 causal pathways (of four steps or less) to PTS at 12 months of police service. Direct causes included single-nucleotide polymorphisms (SNPs) for the Histidine Decarboxylase (HDC) and Mineralocorticoid Receptor (MR) genes, acoustic startle in the context of low perceived threat during training, peritraumatic distress to incident exposure during first year of service, and general symptom severity during training at 1 year of service. The application of CCD methods can determine variables and pathways related to the complex etiology of PTS in a cohort of police officers. This knowledge may inform new approaches to treatment and prevention of critical incident related PTS.

Posttraumatic Stress Disorder and Inflammation: Untangling Issues of Bidirectionality

Posttraumatic stress disorder (PTSD) has increasingly been linked to heightened systemic inflammation. It matters whether this association is causal (and either bidirectional or unidirectional) or correlational. Investigators have hypothesized that chronic systemic low-grade inflammation may contribute to greater risk of developing PTSD after experiencing trauma and/or serve as a mechanism linking PTSD to adverse physical health outcomes. However, if the PTSD-inflammation relation is correlational, it may not warrant further research aimed at understanding inflammation as a PTSD risk factor or as a pathway linking PTSD with poor health. In this review, we first assess the longitudinal evidence related to PTSD and inflammation to understand more clearly the directionality and causal nature of this relation. Overall, few longitudinal studies rigorously assess the direction of the PTSD-inflammation relation. Some of the evidence indicates that elevated inflammation assessed pretrauma or in the acute aftermath of trauma increases risk for developing PTSD. Fewer studies evaluate the influence of PTSD on subsequent inflammation levels, and findings are mixed. Sample characteristics and study designs, and also the type of inflammation-related measure, vary widely across studies. Based on current evidence, we then recommend several statistical and study design approaches that may help untangle issues of bidirectionality and aid in determining the direction of causality between PTSD and inflammation. Last, we conclude with future research directions and consider potential implications for interventions or treatment approaches based on this growing body of literature.

Examining the cardiovascular response to fear extinction in a trauma-exposed sample

BACKGROUND

Trauma and symptoms of posttraumatic stress disorder (PTSD) have repeatedly been linked to impaired cardiovascular functioning. Poor fear extinction is a well-established biomarker of PTSD that may provide insight into mechanisms underlying cardiovascular risk. The current study probed the cardiovascular response to extinction in a sample of trauma-exposed individuals.

METHODS

Participants were 51 trauma-exposed women who underwent a fear conditioning paradigm. Heart rate (HR) during extinction was examined in response to a conditioned stimulus that was previously paired with an aversive unconditioned stimulus (CS+) and one that was never paired (CS-). Heart rate variability (HRV) was calculated at baseline and during the extinction session.

RESULTS

Consistent with fear bradycardia, initial HR deceleration (.5-2s) after CS + onset occurred during early extinction and appeared to extinguish over time. Higher baseline HRV was significantly associated with greater fear bradycardia during early extinction.

CONCLUSIONS

This is the first study to demonstrate a pattern of fear bradycardia in early extinction, which was associated with higher HRV levels and decreased over the course of the extinction phase. These results suggest that increased fear bradycardia may be indicative of greater vagal control (i.e., HRV), both of which are psychophysiological biomarkers that may influence cardiovascular and autonomic disease risk in trauma-exposed individuals.

Amygdala Nuclei Volume and Shape in Military Veterans With Posttraumatic Stress Disorder

BACKGROUND

The amygdala is a subcortical structure involved in socioemotional and associative fear learning processes relevant for understanding the mechanisms of posttraumatic stress disorder (PTSD). Research in animals indicates that the amygdala is a heterogeneous structure in which the basolateral and centromedial divisions are susceptible to stress. While the amygdala complex is implicated in the pathophysiology of PTSD, little is known about the specific contributions of the individual nuclei that constitute the amygdala complex.

METHODS

Military veterans (n = 355), including military veterans with PTSD (n = 149) and trauma-exposed control subjects without PTSD (n = 206), underwent high-resolution T1-weighted anatomical scans. Automated FreeSurfer segmentation of the amygdala yielded 9 structures: basal, lateral, accessory basal, anterior amygdaloid, and central, medial, cortical, and paralaminar nuclei, along with the corticoamygdaloid transition zone. Subregional volumes were compared between groups using ordinary-least-squares regression with relevant demographic and clinical regressors followed by 3-dimensional shape analysis of whole amygdala.

RESULTS

PTSD was associated with smaller left and right lateral and paralaminar nuclei, but with larger left and right central, medial, and cortical nuclei (p < .05, false discovery rate corrected). Shape analyses revealed lower radial distance in anterior bilateral amygdala and lower Jacobian determinant in posterior bilateral amygdala in PTSD compared with control subjects.

CONCLUSIONS

Alterations in select amygdala subnuclear volumes and regional shape distortions are associated with PTSD in military veterans. Volume differences of the lateral nucleus and the centromedial complex associated with PTSD demonstrate a subregion-specific pattern that is consistent with their functional roles in fear learning and fear expression behaviors.

Post-traumatic stress disorder symptom severity attenuates bi-directional associations between negative affect and avoidant coping: A daily diary study

INTRODUCTION

Avoidant coping plays an important role in the maintenance of post-traumatic stress disorder (PTSD). However, existing investigations have been limited in their assessment of coping as a static process - despite evidence that the coping strategies individuals use to manage stressors vary across time and contexts. Further, research has relied on cross-sectional designs, precluding determination of the directionality of the negative affect-avoidant coping association. The current study addresses these limitations by using a daily diary method to examine the moderating role of PTSD symptom severity on reciprocal relations between negative affect and avoidant coping.

METHODS

Participants were 1,188 trauma-exposed adults (M age = 19.2, 56% female, 79% White) who provided daily diary data for 30 days via online surveys. Multi-level models were tested to evaluate the moderating role of PTSD symptom severity in the daily relations between negative affect and avoidant coping during the 30-day period.

RESULTS

Levels of daytime negative affect were assoicated with use of evening avoidant coping. Use of evening avoidant coping were associated with levels of next-day daytime negative affect. PTSD symptom severity moderated these relations. For individuals with more (vs. less) severe PTSD symptoms, the association of negative affect to avoidant coping was weaker and the association of avoidant coping to negative affect was stronger.

LIMITATIONS

Findings must be interpreted in light of limitations, including self-report measures and assessment of a alcohol using sample of college students.

DISCUSSION

These findings advance our understanding of the negative affect-avoidant coping association among trauma-exposed individuals.

The impact of startle reactivity to unpredictable threat on the relation between bullying victimization and internalizing psychopathology

BACKGROUND

Being bullied has detrimental effects on mental health functioning. Individuals who are highly reactive to unpredictable threats (U-threat) may be particularly vulnerable to the negative consequences of being bullied. For them, persistent, unpredictable bullying likely elicits chronic anticipatory anxiety and depression. The aim of the present study was to examine the main and interactive effects of aversive reactivity to U-threat and past-year bullying victimization on current anxiety and depressive symptoms.

METHODS

Seventy-one young adults (ages 17-19) completed a well-validated threat-of-shock task used to probe reactivity to both U-threat and predictable threat (P-threat). Startle eyeblink potentiation was recorded to index aversive responding.

RESULTS

We found a main effect of bullying, such that individuals with more bullying experience exhibited greater anxiety and depressive symptoms than individuals with less bullying experience. There was also a bullying by U-threat reactivity interaction such that among individuals with high reactivity to U-threat, more bullying experience was associated with more anxiety and depressive symptoms. Among individuals with low U-threat reactivity, there was no association between bullying and internalizing symptoms. There were no main or interactive effects involving reactivity to P-threat.

CONCLUSIONS

Together, these results suggest that among individuals who are bullied, those who are sensitive to U-threat are particularly vulnerable to depression and anxiety in young adulthood. These individuals may represent a high-risk group for the development of internalizing psychopathology.

The effects of trauma on brain and body: A unifying role for the midbrain periaqueductal gray

Post-traumatic stress disorder (PTSD), a diagnosis that may follow the experience of trauma, has multiple symptomatic phenotypes. Generally, individuals with PTSD display symptoms of hyperarousal and of hyperemotionality in the presence of fearful stimuli. A subset of individuals with PTSD; however, elicit dissociative symptomatology (i.e., depersonalization, derealization) in the wake of a perceived threat. This pattern of response characterizes the dissociative subtype of the disorder, which is often associated with emotional numbing and hypoarousal. Both symptomatic phenotypes exhibit attentional threat biases, where threat stimuli are processed preferentially leading to a hypervigilant state that is thought to promote defensive behaviors during threat processing. Accordingly, PTSD and its dissociative subtype are thought to differ in their proclivity to elicit active (i.e., fight, flight) versus passive (i.e., tonic immobility, emotional shutdown) defensive responses, which are characterized by the increased and the decreased expression of the sympathetic nervous system, respectively. Moreover, active and passive defenses are accompanied by primarily endocannabinoid- and opioid-mediated analgesics, respectively. Through critical review of the literature, we apply the defense cascade model to better understand the pathological presentation of defensive responses in PTSD with a focus on the functioning of lower-level midbrain and extended brainstem systems.

Video-Based Analysis of Bodily Startle and Subsequent Emotional Facial Expression in Posttraumatic Stress Disorder

Exaggerated startle is a core hyperarousal symptom of Posttraumatic Stress Disorder (PTSD). Observational studies on the characteristics of this response are strikingly lacking. Previous research has demonstrated that detailed video analysis of facial and bodily responses to startling stimuli enables the differentiation of an initial, primarily reflexive response and a secondary, primary emotional response. We exposed PTSD patients (n = 34) and trauma-exposed but healthy participants (TE group, n = 26) to startling electric stimuli while acquiring observational behavioral, psychophysiological, and experiential measures. Videographic results indicate that PTSD patients' initial bodily startle response was stronger than in the TE group, and their secondary facial expression was more negatively valenced, largely due to elevated anger expression. Videographic assessment of primary and secondary startle responses provides a new window into reflexive and emotional functioning of PTSD and may therefore complement existing startle measures. PTSD treatments should address bodily startle, negative symptom appraisals, and anger more specifically.

Child abuse interacts with hippocampal and corpus callosum volume on psychophysiological response to startling auditory stimuli in a sample of veterans

Child abuse (CA), which is linked to posttraumatic stress disorder (PTSD), has been associated with a reduction in both hippocampal and corpus callosum (CC) volume. However, few studies have explored these relationships on psychophysiological variables related to trauma exposure. Therefore, we assessed whether the interaction between CA and hippocampal and CC volume were associated with enhanced fear potentiated psychophysiological response patterns in a sample of Veterans. 147 Veteran participants who were part of a larger study of Gulf War Illness were exposed to startling sounds in no, ambiguous, and high threat conditions and also provided MRI data. The Clinician Administered PTSD Scale and Trauma History Questionnaire were used to measure PTSD and CA respectively. Psychophysiological response was measured by EMG, SCR, and heart rate. Repeated-measures mixed linear models were used to assess the significance of CA by neural structure interactions. CA interacted with both hippocampal and CC volume on psychophysiological response magnitudes, where participants with CA and smaller hippocampal volume had greater EMG (p < 0.01) and SCR (p < 0.05) magnitudes across trials and over threat conditions. Participants with CA and smaller CC volume had greater SCR magnitudes across trials and over threat conditions (p < 0.01). Hippocampal and genu volume mediated CA and psychophysiological response magnitude. CA may impact psychophysiological response via a reduction in hippocampal and CC volume. Volumetric reduction in these structures may indicate a neurofunctional, CA-related increase in threat sensitivity, which could portend increased PTSD susceptibility and adverse interpersonal and social consequences across the lifespan.

A Review of the Relationship Between Emotional Learning and Memory, Sleep, and PTSD

PURPOSE OF REVIEW

The emotional memory and learning model of PTSD posits maladaptive fear conditioning, extinction learning, extinction recall, and safety learning as central mechanisms to PTSD. There is increasingly convincing support that sleep disturbance plays a mechanistic role in these processes. The current review consolidates the evidence on the relationships between emotional memory and learning, disturbed sleep, and PTSD acquisition, maintenance, and treatment.

RECENT FINDINGS

While disrupted sleep prior to trauma predicts PTSD onset, maladaptive fear acquisition does not seem to be the mechanism through which PTSD is acquired. Rather, poor extinction learning/recall and safety learning seem to better account for who maintains acute stress responses from trauma versus who naturally recovers; there is convincing evidence that this process is, at least in part, mediated by REM fragmentation. Individuals with PTSD had higher "fear load" during extinction, worse extinction learning, poorer extinction recall, and worse safety learning. Evidence suggests that these processes are also mediated by fragmented REM. Finally, PTSD treatments that require extinction and safety learning may also be affected by REM fragmentation. Addressing fragmented sleep or sleep architecture could be used to increase emotional memory and learning processes and thus ameliorate responses to trauma exposure, reduce PTSD severity, and improve treatment. Future studies should examine relationships between emotional memory and learning and disturbed sleep in clinical PTSD patients.

Ensemble machine learning prediction of posttraumatic stress disorder screening status after emergency room hospitalization

Posttraumatic stress disorder (PTSD) develops in a substantial minority of emergency room admits. Inexpensive and accurate person-level assessment of PTSD risk after trauma exposure is a critical precursor to large-scale deployment of early interventions that may reduce individual suffering and societal costs. Toward this aim, we applied ensemble machine learning to predict PTSD screening status three months after severe injury using cost-effective and minimally invasive data. Participants (N = 271) were recruited at a Level 1 Trauma Center where they provided variables routinely collected at the hospital, including pulse, injury severity, and demographics, as well as psychological variables, including self-reported current depression, psychiatric history, and social support. Participant zip codes were used to extract contextual variables including population total and density, average annual income, and health insurance coverage rates from publicly available U.S. Census data. Machine learning yielded good prediction of PTSD screening status 3 months post-hospitalization, AUC = 0.85 95% CI [0.83, 0.86], and significantly outperformed all benchmark comparison models in a cross-validation procedure designed to yield an unbiased estimate of performance. These results demonstrate that good prediction can be attained from variables that individually have relatively weak predictive value, pointing to the promise of ensemble machine learning approaches that do not rely on strong isolated risk factors.

Psychophysiological reactivity, coping behaviour and intrusive memories upon multisensory Virtual Reality and Script-Driven Imagery analogue trauma: A randomised controlled crossover study

BACKGROUND

Peri- and post-traumatic factors predict the differential development of stress-associated mental disorders. Prospective designs assessing these risk factors in real-time under controlled experimental conditions can overcome limitations of retrospective designs. Therefore, we aimed to investigate multi-sensory, experimental analogues of a traumatic experience delivered in Virtual Reality (VR) or Script-Driven Imagery (SDI).

METHODS

In a randomised controlled crossover design, differences in the induced analogue trauma symptoms between multi-sensory analogue trauma by either VR or SDI versus a neutral condition were assessed in 127 non-clinical participants.

RESULTS

Analogue symptoms (psychophysiological responses, coping behaviour and intrusive memories of the experimental trauma) increased following analogue trauma in both VR and SDI, with more analogue symptoms for VR. Psychophysiological arousal was in general higher in VR.

LIMITATIONS

The analogue trauma situation of a car park fire that was used may be infrequent in real life.

CONCLUSIONS

Multisensory (vision, olfaction, hearing) analogue trauma in VR and SDI offers a useful tool for the induction and real-time assessment of peri- and post-traumatic risk factors for analogue stress-associated psychopathology. VR was more effective in inducing analogue symptoms than SDI, even though the latter might be more personalised. New experimental models for studying trauma exposure and responses may contribute to a better understanding of risk factors and help to identify and protect individuals at risk.

Association among anterior cingulate cortex volume, psychophysiological response, and PTSD diagnosis in a Veteran sample

Posttraumatic stress disorder (PTSD) is associated with fear response system dysregulation. Research has shown that the anterior cingulate cortex (ACC) may modulate the fear response and that individuals with PTSD have abnormalities in ACC structure and functioning. Our objective was to assess whether ACC volume moderates the relationship between PTSD and fear-potentiated psychophysiological response in a sample of Gulf War Veterans. 142 Veteran participants who were associated with a larger study associated with Gulf War Illness were exposed to no threat, ambiguous threat, and high threat conditions in a fear conditioned startle response paradigm and also provided MRI imaging data. PTSD was assessed using the Clinician Administered PTSD Scale (CAPS). Decreased caudal ACC volume predicted greater psychophysiological responses with a slower habituation of psychophysiological magnitudes across trials (p < 0.001). PTSD diagnosis interacted significantly with both caudal and rostral ACC volumes on psychophysiological response magnitudes, where participants with PTSD and smaller rostral and caudal ACC volumes had greater psychophysiological magnitudes across trials (p < 0.05 and p < 0.001, respectively) and threat conditions (p < 0.05 and p < 0.005). Our results suggest that ACC volume may moderate both threat sensitivity and threat response via impaired habituation in individuals who have been exposed to traumatic events. More research is needed to assess whether ACC size and these associated response patterns are due to neurological processes resulting from trauma exposure or if they are indicative of a premorbid risk for PTSD subsequent to trauma exposure.

Research domain criteria and the study of trauma in children: Implications for assessment and treatment research

By definition, the Diagnostic and Statistical Manual (DSM) diagnosis of posttraumatic stress disorder (PTSD) requires exposure to a traumatic event. Yet, the DSM diagnostic requirements for children and adolescents for PTSD may fail to capture traumatized youth with significant distress and functional impairment. Many important studies have utilized PTSD diagnosis as a mechanism for grouping individuals for comparative studies examining brain functioning, neuroendocrinology, genetics, attachment, and cognition; however, focusing only on those with the diagnosis of PTSD can miss the spectrum of symptoms and difficulties that impact children who experience trauma and subsequent impairment. Some studying child trauma have focused on examining brain and biology of those with exposure and potential impairment rather than only those with PTSD. This line of inquiry, complementary to PTSD specific studies, has aided our understanding of some of the changes in brain structure and neuroregulatory systems at different developmental periods following traumatic exposure. Application of the Research Domain Criteria (RDoC) framework proposed by NIMH to the study of child trauma exposure and subsequent impairment is an opportunity to examine domains of function and how they are impacted by trauma. Research to date has focused largely in the areas of negative valence, regulatory, and cognitive systems, however those studying complex or developmental trauma have identified an array of domains that are impacted which map onto many of the RDoC categories. This paper will review the relevant literature associated with child trauma as it relates to the RDoC domains, outline areas of needed research, and describe their implications for treatment and the advancement of the field.

Effects of Threat Context, Trauma History, and Posttraumatic Stress Disorder Status on Physiological Startle Reactivity in Gulf War Veterans

In the current study, we explored exaggerated physiological startle responses in posttraumatic stress disorder (PTSD) and examined startle reactivity as a biomarker of PTSD in a large veteran sample. We assessed heart rate (HR), skin conductance (SC), and electromyographic (EMG) startle responses to acoustic stimuli under low-, ambiguous-, and high-threat conditions in Gulf War veterans with current (n = 48), past (n = 42), and no history of PTSD (control group; n = 152). We evaluated PTSD status using the Clinician-Administered PTSD Scale and trauma exposure using the Trauma History Questionnaire. Participants with current PTSD had higher HR, ds = 0.28-0.53; SC, d = 0.37; and startle responses than those with past or no history of PTSD. The HR startle response under ambiguous threat best differentiated current PTSD; however, sensitivity and specificity analyses revealed it to be an imprecise indicator of PTSD status, ROC AUC = .66. Participants with high levels of trauma exposure only showed elevated HR and SC startle reactivity if they had current PTSD. Results indicate that startle is particularly elevated in PTSD when safety signals are available but a possibility of danger remains and when trauma exposure is high. However, startle reactivity alone is unlikely to be a sufficient biomarker of PTSD.

A systematic review of the usefulness of pre-employment and pre-duty screening in predicting mental health outcomes amongst emergency workers

Despite a lack of proven efficacy, pre-employment or pre-duty screening, which alleges to test for vulnerability to PTSD and other mental health disorders, remains common amongst emergency services. This systematic review aimed to determine the usefulness of different factors in predicting mental disorder amongst emergency workers and to inform practice regarding screening procedures. Systematic searches were conducted in MEDLINE, PsycINFO and EMBASE to identify cohort studies linking pre-employment or pre-duty measures in first responders with later mental health outcomes. Possible predictors of poor mental health were grouped into six categories and their overall level of evidence was assessed. Twenty-one prospective cohort studies were identified. Dynamic measures including physiological responses to simulated trauma and maladaptive coping styles (e.g. negative self-appraisal) had stronger evidence as predictors of vulnerability in first responders than more traditional static factors (e.g. pre-existing psychopathology). Personality factors (e.g. trait anger) had moderate evidence for predictive power. Based on the evidence reviewed, however, we are unable to provide emergency services with specific information to enhance their current personnel selection. The results indicate that pre-duty screening protocols that include personality assessments and dynamic measures of physiological and psychological coping strategies may be able to identify some personnel at increased risk of mental health problems. However, further longitudinal research is required in order to provide meaningful guidance to employers on the overall utility of either pre-employment or pre-duty screening. In particular, research examining the sensitivity, specificity and positive predictive values of various screening measures is urgently needed.

Neural Biomarker and Early Temperament Predict Increased Internalizing Symptoms After a Natural Disaster

OBJECTIVE

Although most people will experience a traumatic event at some point in their life, only some will develop significant psychological symptoms in the aftermath. In the current study, we use a preexisting longitudinal study located in Long Island to examine the impact of Hurricane Sandy on internalizing symptoms in a large sample of children. We focused on temperamental fear and a biomarker of risk for anxiety, the error-related negativity (ERN). The ERN is a negative deflection in the event-related potential (ERP) occurring when individuals make mistakes and is increased in anxious individuals.

METHOD

The final sample consisted of 223 children who had undergone an observational assessment of fear at age 3 years and an electroencephalogram assessment of the ERN at age 6 years. At the age 9 year assessment, internalizing symptoms were assessed, and then again after the hurricane (∼65 weeks later).

RESULTS

A significant three-way interaction among fearfulness, hurricane stressors, and the ERN in predicting posthurricane increases in internalizing symptoms suggested that children who were high in fear at age 3 years and experienced elevated hurricane stressors were characterized by subsequent increases in internalizing symptoms, but only when they were also characterized by an increased ERN at age 6 years.

CONCLUSION

These findings support a diathesis-stress model, suggesting that early temperament and prestressor biological markers confer risk for increased psychological symptoms following environmental stressors.

Acoustic startle response in rats predicts inter-individual variation in fear extinction

Although a large portion of the population is exposed to a traumatic event at some point, only a small percentage of the population develops post-traumatic stress disorder (PTSD), suggesting the presence of predisposing factors. Abnormal acoustic startle response (ASR) has been shown to be associated with PTSD, implicating it as a potential predictor of the development of PTSD-like behavior. Since poor extinction and retention of extinction learning are characteristic of PTSD patients, it is of interest to determine if abnormal ASR is predictive of development of such deficits. To determine whether baseline ASR has utility in predicting the development of PTSD-like behavior, the relationship between baseline ASR and freezing behavior following Pavlovian fear conditioning was examined in a group of adult, male Sprague-Dawley rats. Baseline acoustic startle response (ASR) was assessed preceding exposure to a Pavlovian fear conditioning paradigm where freezing behavior was measured during fear conditioning, extinction training, and extinction testing. Although there was no relationship between baseline ASR and fear memory following conditioning, rats with low baseline ASR had significantly lower magnitude of retention of the extinction memory than rats with high baseline ASR. The results suggest that baseline ASR has value as a predictive index of the development of a PTSD-like phenotype.

Post-traumatic stress disorder and cardiometabolic disease: improving causal inference to inform practice

Post-traumatic stress disorder (PTSD) has been declared 'a life sentence' based on evidence that the disorder leads to a host of physical health problems. Some of the strongest empirical research - in terms of methodology and findings - has shown that PTSD predicts higher risk of cardiometabolic diseases, specifically cardiovascular disease (CVD) and type 2 diabetes (T2D). Despite mounting evidence, PTSD is not currently acknowledged as a risk factor by cardiovascular or endocrinological medicine. This view is unlikely to change absent compelling evidence that PTSD causally contributes to cardiometabolic disease. This review suggests that with developments in methods for epidemiological research and the rapidly expanding knowledge of the behavioral and biological effects of PTSD the field is poised to provide more definitive answers to questions of causality. First, we discuss methods to improve causal inference using the observational data most often used in studies of PTSD and health, with particular reference to issues of temporality and confounding. Second, we consider recent work linking PTSD with specific behaviors and biological processes, and evaluate whether these may plausibly serve as mechanisms by which PTSD leads to cardiometabolic disease. Third, we evaluate how looking more comprehensively into the PTSD phenotype provides insight into whether specific aspects of PTSD phenomenology are particularly relevant to cardiometabolic disease. Finally, we discuss new areas of research that are feasible and could enhance understanding of the PTSD-cardiometabolic relationship, such as testing whether treatment of PTSD can halt or even reverse the cardiometabolic risk factors causally related to CVD and T2D.

The role of automatic defensive responses in the development of posttraumatic stress symptoms in police recruits: protocol of a prospective study

Background: Control over automatic tendencies is often compromised in challenging situations when people fall back on automatic defensive reactions, such as freeze-fight-flight responses. Stress-induced lack of control over automatic defensive responses constitutes a problem endemic to high-risk professions, such as the police. Difficulties controlling automatic defensive responses may not only impair split-second decisions under threat, but also increase the risk for and persistence of posttraumatic stress disorder (PTSD) symptoms. However, the significance of these automatic defensive responses in the development and maintenance of trauma-related symptoms remains unclear due to a shortage of large-scale prospective studies. Objective: The 'Police-in-Action' study is conducted to investigate the role of automatic defensive responses in the development and maintenance of PTSD symptomatology after trauma exposure. Methods: In this prospective study, 340 police recruits from the Dutch Police Academy are tested before (wave 1; pre-exposure) and after (wave 2; post-exposure) their first emergency aid experiences as police officers. The two waves of data assessment are separated by approximately 15 months. To control for unspecific time effects, a well-matched control group of civilians (n = 85) is also tested twice, approximately 15 months apart, but without being frequently exposed to potentially traumatic events. Main outcomes are associations between (changes in) behavioural, psychophysiological, endocrine and neural markers of automatic defensive responses and development of trauma-related symptoms after trauma exposure in police recruits. Discussion: This prospective study in a large group of primary responders enables us to distinguish predisposing from acquired neurobiological abnormalities in automatic defensive responses, associated with the development of trauma-related symptoms. Identifying neurobiological correlates of (vulnerability for) trauma-related psychopathology may greatly improve screening for individuals at risk for developing PTSD symptomatology and offer valuable targets for (early preventive) interventions for PTSD.

Reduced Freezing in Posttraumatic Stress Disorder Patients while Watching Affective Pictures

Besides fight and flight responses, animals and humans may respond to threat with freezing, a response characterized by bradycardia and physical immobility. Risk assessment is proposed to be enhanced during freezing to promote optimal decision making. Indeed, healthy participants showed freezing-like responses to threat cues. Posttraumatic stress disorder (PTSD) patients are characterized by hypervigilance and increased threat responsiveness. We propose that threat responses will be characterized by decreased freezing in PTSD, eliminating possibilities for rejecting cognitive distortions, such as harm expectancy, and thereby contributing to the maintenance of the disorder. However, freezing responses have hardly been investigated in PTSD. Using a stabilometric platform to assess body sway as an indicator of freezing-like behavior, we examined whether veterans with PTSD would show diminished freezing responses to unpleasant versus neutral and pleasant pictures. Fourteen PTSD patients and 14 healthy matched controls watched the pictures, while body sway and heart rate (HR) were continuously assessed. Replicating previous findings, healthy controls showed decreased body sway and HR in response to unpleasant pictures, indicative of freezing-like behavior. In contrast, this response pattern was not observed in PTSD patients. The results may indicate a reduced freezing response in PTSD. As reduced freezing may hinder appropriate risk assessment, it may be an important factor in the maintenance of PTSD. Future research might clarify whether impaired freezing is a PTSD-specific or a transdiagnostic symptom, being present in threat-related disorders.

Preventing PTSD with oxytocin: effects of oxytocin administration on fear neurocircuitry and PTSD symptom development in recently trauma-exposed individuals

Background: Posttraumatic stress disorder (PTSD) is a debilitating psychiatric disorder which develops in approximately 10% of trauma-exposed individuals. Currently, there are few early preventive interventions available for PTSD. Intranasal oxytocin administration early posttrauma may prevent PTSD symptom development, as oxytocin administration was previously found to beneficially impact neurobiological (e.g. amygdala reactivity) and socio-emotional PTSD vulnerability factors. Objective: The overall aim of this dissertation was to investigate the potential of intranasal oxytocin administration as early preventive intervention for PTSD. Methods: We performed a functional magnetic resonance imaging (fMRI) study to assess the acute effects of a single administration of oxytocin on the functional fear neurocircuitry - consisting of the amygdala and (pre)frontal brain regions - in recently trauma-exposed emergency department patients (range n = 37-41). In addition, we performed a multicentre randomized double-blind placebo-controlled clinical trial (RCT) to assess the efficacy of repeated intranasal oxytocin administration early after trauma for preventing PTSD symptom development up to six months posttrauma (n = 107). Results: In our fMRI experiments we observed acutely increased amygdala reactivity to fearful faces and attenuated amygdala-ventromedial and ventrolateral prefrontal cortex functional connectivity after a single oxytocin administration in recently trauma-exposed individuals. However, in our RCT we found that repeated intranasal oxytocin administration early posttrauma reduced subsequent PTSD symptom development in recently trauma-exposed emergency department patients with high acute PTSD symptoms. Conclusions: These findings indicate that repeated intranasal oxytocin is a promising early preventive intervention for PTSD for individuals at increased risk for PTSD due to high acute symptom severity. Administration frequency dependent effects of oxytocin or the effects of oxytocin administration on salience processing may serve as explanatory frameworks for the contrasting oxytocin effects on anxiety-related measures in our clinical and neuroimaging studies.

Heart rate variability: Pre-deployment predictor of post-deployment PTSD symptoms

Heart rate variability is a physiological measure associated with autonomic nervous system activity. This study hypothesized that lower pre-deployment HRV would be associated with higher post-deployment post-traumatic stress disorder (PTSD) symptoms. Three-hundred-forty-three Army National Guard soldiers enrolled in the Warriors Achieving Resilience (WAR) study were analyzed. The primary outcome was PTSD symptom severity using the PTSD Checklist - Military version (PCL) measured at baseline, 3- and 12-month post-deployment. Heart rate variability predictor variables included: high frequency power (HF) and standard deviation of the normal cardiac inter-beat interval (SDNN). Generalized linear mixed models revealed that the pre-deployment PCL*ln(HF) interaction term was significant (p<0.0001). Pre-deployment SDNN was not a significant predictor of post-deployment PCL. Covariates included age, pre-deployment PCL, race/ethnicity, marital status, tobacco use, childhood abuse, pre-deployment traumatic brain injury, and previous combat zone deployment. Pre-deployment heart rate variability predicts post-deployment PTSD symptoms in the context of higher pre-deployment PCL scores.

Cortisol, heart rate, and blood pressure as early markers of PTSD risk: A systematic review and meta-analysis

Individuals with posttraumatic stress disorder (PTSD) typically exhibit altered hypothalamic-pituitary-adrenal (HPA) function and sympathetic nervous system (SNS) activity. The goals of this study were to determine whether HPA and SNS alterations in the immediate aftermath of trauma predict subsequent PTSD symptom development and whether inconsistencies observed between studies can be explained by key demographic and methodological factors. This work informs secondary prevention of PTSD by identifying subgroups of trauma survivors at risk for PTSD. This meta-analysis (26 studies, N=5186 individuals) revealed that higher heart rate measured soon after trauma exposure was associated with higher PTSD symptoms subsequently (r=0.13). Neither cortisol (r=-0.07) nor blood pressure (diastolic: r=-0.01; systolic: r=0.02) were associated with PTSD symptoms which may be influenced by methodological limitations. Associations between risk markers (heart rate, cortisol, systolic blood pressure) and PTSD symptoms were in the positive direction for younger samples and negative direction for older samples. These findings extend developmental traumatology models of PTSD by revealing an age-related shift in the presentation of early risk markers. More work will be needed to identify risk markers and pathways to PTSD while addressing methodological limitations in order to shape and target preventive interventions.