Exploration of a Novel Model of Intrusive Symptoms in Posttraumatic Stress Disorder Among US Veterans

Emotional State Transitions in Trauma-Exposed Individuals With and Without Posttraumatic Stress Disorder

Importance

Posttraumatic stress disorder (PTSD) is marked by the contrasting symptoms of hyperemotional reactivity and emotional numbing (ie, reduced emotional reactivity). Comprehending the mechanism that governs the transition between neutral and negative emotional states is crucial for developing targeted therapeutic strategies.

Objectives

To explore whether individuals with PTSD experience a more pronounced shift between neutral and negative emotional states and how the intensity of emotional numbing symptoms impacts this shift.

Design, Setting, and Participants

This cross-sectional study used hierarchical bayesian modeling to fit a 5-parameter logistic regression to analyze the valence ratings of images. The aim was to compare the curve's slope between groups and explore its association with the severity of emotional numbing symptoms. The study was conducted online, using 35 images with a valence range from highly negative to neutral. The rating of these images was used to assess the emotional responses of the participants. The study recruited trauma-exposed individuals (witnessed or experienced life-threatening incident, violent assault, or someone being killed) between January 17 and March 8, 2023. Participants completed the PTSD Checklist for the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-5) (PCL-5).

Exposure

On the basis of DSM-5 criteria (endorsing at least 1 symptom from clusters B and C and 2 from D and E), participants were categorized as having probable PTSD (pPTSD) or as trauma-exposed controls (TECs).

Main Outcomes and Measures

The main outcome was the slope parameter (b) of the logistic curve fitted to the valence rating. The slope parameter indicates the rate at which emotional response intensity changes with stimulus valence, reflecting how quickly the transition occurs between neutral and negatively valenced states. The secondary outcome was the association between emotional numbing (PCL-5 items 12-14) and the slope parameter.

Results

A total of 1440 trauma-exposed individuals were included. The pPTSD group (n = 445) was younger (mean [SD] age, 36.1 [10.9] years) compared with the TEC group (mean [SD] age, 41.5 [13.3] years; P < .001). Sex distribution (427 women in the TEC group vs 230 in the pPTSD group) did not significantly differ between groups (P = .67). The pPTSD group exhibited a steeper slope (mean slope difference, -0.255; 89% highest posterior density [HPD], -0.340 to -0.171) compared with the controls. Across all individuals (n = 1440), a robust association was found between the slope and emotional numbing severity (mean [SD] additive value, 0.100 [0.031]; 89% HPD, 0.051-0.15). Additional analysis controlling for age confirmed the association between emotional numbing and transition sharpness (mean [SD] additive value, 0.108 [0.032]; 89% HPD, 0.056-0.159), without evidence of an age-related association (mean [SD] additive value, 0.031 [0.033]; 89% HPD, -0.022 to 0.083).

Conclusions and Relevance

These findings support that individuals with PTSD undergo rapid transitions between neutral and negative emotional states, a phenomenon intensified by the severity of emotional numbing symptoms. Therapeutic interventions aimed at moderating these swift emotional transitions could potentially alleviate PTSD symptoms.

Posttraumatic Growth in U.S. Military Veterans: Results from the National Health and Resilience in Veterans Study

Despite increasing recognition that positive psychological changes or posttraumatic growth (PTG) may develop after highly stressful or traumatic events, contemporary population-based data on the epidemiology of PTG in high-risk samples such as U.S. military veterans are lacking. Additionally, in light of emerging evidence suggesting an 8-factor model of posttraumatic stress disorder (PTSD) symptoms, an up-to-date characterization of how these symptom clusters relate to PTG can help inform efforts to help promote PTG. Data were analyzed from the 2019-2020 National Health and Resilience in Veterans Study (NHRVS), which surveyed a nationally representative sample of 3,847 trauma-exposed U.S. veterans. Participants completed assessments of potentially traumatic events, PTSD symptoms, and PTG, as well as a broad range of sociodemographic, military, trauma, health, personality, and psychosocial characteristics. Results revealed that 63.2% of trauma-exposed veterans and 86.4% of veterans who screened positive for PTSD endorsed moderate-or-greater PTG; these prevalences are higher than those reported in an independent U.S. veteran sample in 2011 (50.1% and 72.0%, respectively). An inverted U-shaped association was observed between PTSD symptom severity and PTG levels, with scores of 31 to 51 on the PTSD Checklist for DSM-5 associated with the highest likelihood of PTG. Intrinsic religiosity and internally- and externally-generated intrusive symptoms of PTSD were identified as the strongest correlates of PTG. Results suggest that prevention and treatment efforts to mitigate severe PTSD symptoms, and help promote intrinsic religiosity, and more deliberate and organized rumination about traumatic experiences may help foster PTG in veterans.

Functional correlates of a novel 8-factor model of PTSD in U.S. military veterans: Results from the National Health and Resilience in Veterans Study

Emerging evidence indicates that more nuanced models of posttraumatic stress disorder (PTSD) may better capture the condition's symptom structure. Recent theoretical and empirical work suggest that an 8-factor model of PTSD with separate internally- (e.g. flashbacks) and externally- (e.g. trauma-cue related physiological reactivity) generated intrusive symptom clusters may advance understanding of PTSD and its treatment and course. However, the model's functional and clinical significance still requires evaluation. To this end, we analyzed data from the National Health and Resilience in Veterans Study, a nationally representative sample of 3847 trauma-exposed U.S. military veterans. Multivariable regressions were performed to assess the relationship between the 8 PTSD symptom clusters, assessed using the PTSD Checklist for DSM-5, and clinical and functional measures. Results revealed that externally-generated intrusions were associated with higher odds of current depression and anxiety and worse mental, cognitive, and psychosocial functioning. Anhedonia (e.g., loss of interest in enjoyable activities) symptoms were associated with all the correlates tested, while negative affect (e.g., having strong negative feelings such as fear) symptoms were associated with all measures except depression. Avoidance symptoms were associated with lower odds of current anxiety while externalizing behavior symptoms were linked to higher odds of suicidal ideation. Anxious arousal symptoms were associated with lower odds of suicidal ideation but higher odds of PTSD-related impairment/distress, while dysphoric arousal symptoms were associated with higher odds of current depression, PTSD-related impairment/distress and worse mental and cognitive functioning. Results suggest that a more nuanced 8-factor model of PTSD symptoms may help inform understanding of the clinical and functional correlates of this multi-faceted disorder.

Evaluating a novel 8-factor dimensional model of PTSD in U.S. military veterans: Results from the National Health and Resilience in Veterans Study

BACKGROUND

Accumulating data suggest that the structure of posttraumatic stress disorder (PTSD) symptoms may be more nuanced than proposed by prevailing nosological models. Emerging theory further suggests that an 8-factor model with separate internally- (e.g., flashbacks) and externally- (e.g., trauma cue-related emotional reactivity) generated intrusive symptoms may best represent PTSD symptoms. To date, however, scarce research has evaluated the fit of this model and whether index traumas are differentially associated with it in populations at high risk for trauma exposure, such as military veterans.

METHODS

Data were analyzed from a nationally representative sample of 3847 trauma-exposed U.S. veterans who participated in the National Health and Resilience in Veterans Study. Confirmatory factor analyses were conducted to evaluate the fit of a novel 8-factor model of PTSD symptoms relative to 4-factor DSM-5 and empirically-supported 7-factor hybrid models.

RESULTS

The 8-factor model fit the data significantly better than the 7-factor hybrid and 4-factor DSM-5 models. Combat exposure and harming others were more strongly associated with internally-generated intrusions, while interpersonal violence and disaster/accident showed stronger significant associations with externally-generated intrusions.

LIMITATIONS

The 8-factor model requires validation in non-veteran and more diverse trauma-exposed populations, as well as with clinician-administered interviews.

CONCLUSIONS

Results of this study provide support for a novel 8-factor model of PTSD symptoms that is characterized by separate internally- and externally-generated intrusions. They also suggest that certain index traumas may lead to differential expression of these symptoms.

Not all traumas are created equal: Phenotypic heterogeneity of PTSD symptoms in relation to index traumas in U.S. military veterans

Posttraumatic stress disorder (PTSD) is prevalent in military veterans. Although exposure to trauma is subsumed under the diagnostic criteria for PTSD, there is great variability in index traumatic events, and the clinical presentation of PTSD may vary in individuals depending on the type of event experienced. We examined the relationship between different index traumas and PTSD symptoms in 3507 trauma-exposed U.S. military veterans who participated in the National Health and Resilience in Veterans Study. Results showed that interpersonal violence and combat/captivity was associated with greater overall severity of PTSD symptoms relative to illness/injury and disaster/accident. Interpersonal violence and combat/captivity were also associated with greater severity of intrusive, avoidance, negative affect, anhedonia, externalizing behaviors, and anxious and dysphoric arousal symptoms, relative to the other two categories. Implications of these findings for tailoring treatment approaches for PTSD in veterans are discussed.

Network analysis of posttraumatic stress disorder in a treatment-seeking sample of US firefighters and emergency medical technicians

BACKGROUND

First responders, including firefighters and emergency medical technicians (EMTs), are under extreme stress from repeated exposure to potentially traumatic events. To optimize treatment for this population, it is critical to understand how the various posttraumatic stress disorder (PTSD) symptom factors are associated with one another so these relations may be targeted in treatment.

METHOD

Using a sample of treatment-seeking firefighters/EMTs (N = 342), we conducted a partial correlation network analysis of the eight-factor model. A Bayesian directed acyclic graph (DAG) was used to estimate causal associations between clusters.

RESULTS

Approximately 37 % of the sample screened positive for probable PTSD. Internal re-experiencing and external re-experiencing had the strongest edges. In the DAG, internal re-experiencing was the parent node and was potentially predictive of external re-experiencing, negative affect, dysphoric arousal, and avoidance.

LIMITATIONS

Data were drawn from a treatment-seeking sample that may not generalize to all firefighters/EMTs.

CONCLUSIONS

The current findings are consistent with prior research suggesting re-experiencing plays a critical role in developing and maintaining PTSD symptoms. Future research should investigate non-treatment-seeking first responders, as well as EMTs and firefighters as individual populations.

Correlates of avoidance coping in trauma-exposed U.S. military veterans: Results from the National Health and Resilience in Veterans Study

Avoidant coping strategies, which involve cognitions and behaviors aimed to avoid dealing with stressful experiences, are associated with adverse long-term mental and physical health outcomes. In response to traumatic events, these strategies can be maladaptive as they may interfere with the adaptive integration of traumatic events into consolidated memories. Using data from a nationally representative sample of more than 3000 trauma-exposed U.S. military veterans (mean time since trauma 30.9 years, SD = 19.9), we employed a network analytic approach to examine pairwise associations between key sociodemographic, personality, and psychosocial risk factors in relation to the endorsement of avoidant coping strategies. Results revealed that negative affect symptoms of posttraumatic stress disorder (PTSD) and adverse childhood experiences were positively associated with engagement in avoidance coping, and that greater emotional stability and conscientiousness were negatively associated with this measure. Secondary network analysis of individual negative affect symptoms of PTSD suggested that blaming oneself and/or others for the traumatic event, emotional neglect, and sexual abuse were most strongly linked to avoidance coping. Collectively, these results suggest that strong feelings of blame related to trauma, emotional neglect, and sexual abuse are associated with greater likelihood of engaging in avoidance coping, while emotional stability and conscientiousness are associated with a lower likelihood of engaging in such strategies.

Long term structural and functional neural changes following a single infusion of Ketamine in PTSD

NMDA receptor antagonists have a vital role in extinction, learning, and reconsolidation processes. During the reconsolidation window, memories are activated into a labile state and can be reconsolidated in an altered form. This concept might have significant clinical implications in treating PTSD. In this pilot study we tested the potential of a single infusion of ketamine, followed by brief exposure therapy, to enhance post-retrieval extinction of PTSD trauma memories. 27 individuals diagnosed with PTSD were randomly assigned to receive either ketamine (0.5 mg/kg 40 min; N = 14) or midazolam (0.045 mg/kg; N = 13) after retrieval of the traumatic memory. 24 h following infusion, participants received a four-day trauma-focused psychotherapy. Symptoms and brain activity were assessed before treatment, at the end of treatment, and at 30-day follow-up. Amygdala activation to trauma scripts (a major biomarker of fear response) served as the main study outcome. Although PTSD symptoms improved equally in both groups, post-treatment, ketamine recipients showed a lower amygdala (-0.33, sd = 0.13, 95%HDI [-0.56,-0.04]) and hippocampus (-0.3 (sd = 0.19), 95%HDI [-0.65, 0.04]; marginal effect) reactivation to trauma memories, compared to midazolam recipients. Post-retrieval ketamine administration was also associated with decreased connectivity between the amygdala and hippocampus (-0.28, sd = 0.11, 95%HDI [-0.46, -0.11]), with no change in amygdala-vmPFC connectivity. Moreover, reduction in fractional anisotropy in bi-lateral uncinate fasciculus was seen in the Ketamine recipients compared with the midazolam recipients (right: post-treatment: -0.01108, 95% HDI [-0.0184,-0.003]; follow-up: -0.0183, 95% HDI [-0.02719,-0.0107]; left: post-treatment: -0.019, 95% HDI [-0.028,-0.011]; follow-up: -0.017, 95% HDI [-0.026,-0.007]). Taken together it is possible that ketamine may enhance post-retrieval extinction of the original trauma memories in humans. These preliminary findings show promising direction toward the capacity to rewrite human traumatic memories and modulate the fear response for at least 30 days post-extinction. When combined with psychotherapy for PTSD, further investigation of ketamine dose, timing of administration, and frequency of administration, is warranted.

Clinical significance of novel 8-factor model of DSM-5 PTSD in national VA PTSD residential treatment data: Internally- v. externally-cued intrusions

BACKGROUND

Intrusion symptoms are a core defining feature of posttraumatic stress disorder (PTSD). It was recently proposed that intrusions may be comprised of two distinct underlying processes: internally-cued intrusions (e.g., trauma-related memories), and externally-cued intrusions (e.g., reactivity to trauma-related cues in one's environment). This is the first study to examine the functional correlates of these two intrusion clusters.

METHODS

Participants included 7460 veterans discharged from 40 Veterans Affairs PTSD residential programs across the United States in fiscal years 2018 through 2020. Latent network modeling and structural equation modeling were used to assess the fit of an 8-factor model of PTSD symptoms, which were assessed using the PTSD Checklist for DSM-5 (PCL-5) PTSD symptoms at admission, and its association with symptoms of depression and generalized anxiety, and emotional and physical functioning.

RESULTS

The 8-factor model, with separate intrusion factors, showed superior model fit to the DSM-5 4-factor, 5-factor dysphoric arousal, 6-factor anhedonia, and 7-factor hybrid models of PTSD. Internally-cued intrusions were uniquely associated with dysphoric arousal, decreased avoidance, and worse physical health functioning; whereas, externally-cued intrusions were uniquely associated with greater avoidance, anxious arousal, negative affect, increased generalized anxiety symptoms, and worse emotional functioning.

LIMITATIONS

Limitations include the cross-sectional design and use of self-report measures.

CONCLUSIONS

Findings provide initial support for the clinical utility of a novel 8-factor model of PCL-5 PTSD symptoms, which distinguishes internally- and externally-cued intrusions. These separate intrusion symptom clusters may offer greater specificity and utility in informing the prognosis of and tailored interventions for PTSD.