A reciprocal inhibition model of alternations between under-/overemotional modulatory states in patients with PTSD

Influence of affective instability on suicidal ideation beyond traumatic brain injury and posttraumatic stress disorder in veterans

OBJECTIVE

Mild traumatic brain injury (TBI) is associated with long-term consequences, including greater risk for posttraumatic stress disorder (PTSD) and suicidal ideation. Affective instability is also independently related to PTSD and suicidality, which may explain why some individuals continue to experience chronic psychiatric complaints following mild TBI. The purpose of the present study was to evaluate affective instability as a key factor for PTSD and suicidal ideation among Veterans with and without TBI.

METHOD

Participants (N = 299 Veterans; 86.96% male) completed the Personality Assessment Inventory (PAI) and structured clinical interviews for TBI and psychiatric diagnoses. Hierarchical linear regression was used to evaluate main and interaction effects.

RESULTS

There were no significant differences in affective instability (p = 0.140) or suicidal ideation (p = 0.453) between Veterans with or without TBI. Individuals with TBI were more likely to have a PTSD diagnosis (p = 0.001). Analyses evaluating PTSD diagnosis as an outcome indicated a main effect of affective instability (p < 0.001), but not TBI (p = 0.619). Analyses evaluating suicidal ideation as an outcome demonstrated an interaction effect between PTSD and affective instability beyond the effects of TBI (p = 0.034).

CONCLUSIONS

Severe Affective instability appears to be a key factor in suicidal ideation among Veterans beyond TBI or PTSD history. PTSD was more strongly associated with suicidality at lower and moderate levels of affective instability. At severe levels of affective instability, however, Veterans with and without PTSD experienced suicidal ideation at similar rates. Findings suggests that high levels of affective instability not better explained by other psychiatric conditions confers similar suicidality risk to that of PTSD in a Veteran population.

The nested hierarchical model of self and its non-relational vs relational posttraumatic manifestation: an fMRI meta-analysis of emotional processing

Different kinds of traumatic experiences like natural catastrophes vs. relational traumatic experiences (e.g., sex/physical abuse, interpersonal partner violence) are involved in the development of the self and PTSD psychopathological manifestations. Looking at a neuroscience approach, it has been proposed a nested hierarchical model of self, which identifies three neural-mental networks: (i) interoceptive; (ii) exteroceptive; (iii) mental. However, it is still unclear how the self and its related brain networks might be affected by non-relational vs relational traumatic experiences. Departing from this background, the current study aims at conducting a meta-analytic review of task-dependent fMRI studies (i.e., emotional processing task) among patients with PTSD due to non-relational (PTSD-NR) and relational (PTSD-R) traumatic experiences using two approaches: (i) a Bayesian network meta-analysis for a region-of-interest-based approach; (ii) a coordinated-based meta-analysis. Our findings suggested that the PTSD-NR mainly recruited areas ascribed to the mental self to process emotional stimuli. Whereas, the PTSD-R mainly activated regions associated with the intero-exteroceptive self. Accordingly, the PTSD-R compared to the PTSD-NR might not reach a higher symbolic capacity to process stimuli with an emotional valence. These results are also clinically relevant in support of the development of differential treatment approaches for non-relational vs. relational PTSD.

Treatment of Posttraumatic Stress Disorder: A State-of-the-art Review

This narrative state-of-the-art review paper describes the progress in the understanding and treatment of Posttraumatic Stress Disorder (PTSD). Over the last four decades, the scientific landscape has matured, with many interdisciplinary contributions to understanding its diagnosis, etiology, and epidemiology. Advances in genetics, neurobiology, stress pathophysiology, and brain imaging have made it apparent that chronic PTSD is a systemic disorder with high allostatic load. The current state of PTSD treatment includes a wide variety of pharmacological and psychotherapeutic approaches, of which many are evidence-based. However, the myriad challenges inherent in the disorder, such as individual and systemic barriers to good treatment outcome, comorbidity, emotional dysregulation, suicidality, dissociation, substance use, and trauma-related guilt and shame, often render treatment response suboptimal. These challenges are discussed as drivers for emerging novel treatment approaches, including early interventions in the Golden Hours, pharmacological and psychotherapeutic interventions, medication augmentation interventions, the use of psychedelics, as well as interventions targeting the brain and nervous system. All of this aims to improve symptom relief and clinical outcomes. Finally, a phase orientation to treatment is recognized as a tool to strategize treatment of the disorder, and position interventions in step with the progression of the pathophysiology. Revisions to guidelines and systems of care will be needed to incorporate innovative treatments as evidence emerges and they become mainstream. This generation is well-positioned to address the devastating and often chronic disabling impact of traumatic stress events through holistic, cutting-edge clinical efforts and interdisciplinary research.

Blunted neurobiological reactivity and attentional bias to threat underlie stress-related disorders in women survivors of intimate partner violence

BACKGROUND

Intimate partner violence (IPV) alters women's neurobiological stress response systems. We propose that individual differences early in the attentional processing of threats are associated with these neurobiological mechanisms and contribute to mental illness in this population.

METHODS

We assessed attentional bias in relation to threat (AB) in women survivors of IPV (n = 69) and controls (n = 36), and examined overall cortisol secretion using hair cortisol (HC), and stress responsiveness measuring salivary cortisol and α-amylase (sAA) before (T0), and after (T1, T2) an acute psychosocial stress task (Trier Social Stress Test). We used repeated-measures ANCOVAs to explore the associations between Group (IPV, control) and AB with acute stress response, and regression models to examine the associations with mental health symptoms.

RESULTS

There were no between-group differences in HC levels. An interaction between Group and AB was found regarding cortisol reactivity (p < 0.05). IPV women with threat avoidance AB showed a blunted cortisol response compared to controls and to IPV participants with threat vigilance AB. The association between sAA reactivity and the interaction between Group, AB, and time approached significance (p = 0.07), with a trend to lower sAA levels particularly in IPV women with threat avoidance AB. Group and cortisol reactivity were associated with symptoms of depression, generalized anxiety, and post-traumatic stress disorder (8-20% explained variance).

CONCLUSIONS

Threat avoidance AB is associated with blunted acute cortisol response among women exposed to chronic stress (IPV). Experiencing IPV and acute cortisol response appear to be clearly implicated in long-term mental health problems.

Hyperacusis is associated with smaller gray matter volumes in the supplementary motor area

Hyperacusis is a disorder in loudness perception characterized by increased sensitivity to ordinary environmental sounds and associated with otologic conditions, including hearing loss and tinnitus (the phantom perception of sound) as well as neurologic and neuropsychiatric conditions. Hyperacusis is believed to arise centrally in the brain; however, the underlying causes are unknown. To gain insight into differences in brain morphology associated with hyperacusis, we undertook a retrospective case-control study comparing whole-brain gray matter morphology in participants with sensorineural hearing loss and tinnitus who either scored above or below the threshold for hyperacusis based on a standard questionnaire. We found that participants reporting hyperacusis had smaller gray matter volumes and cortical sheet thicknesses in the right supplementary motor area (SMA), independent of anxiety, depression, tinnitus burden, or sex. In fact, the right SMA volumes extracted from an independently defined volume of interest could accurately classify participants. Finally, in a subset of participants where functional data were also available, we found that individuals with hyperacusis showed increased sound-evoked responses in the right SMA compared to individuals without hyperacusis. Given the role of the SMA in initiating motion, these results suggest that in hyperacusis the SMA is involved in a motor response to sounds.

Towards assessing subcortical "deep brain" biomarkers of PTSD with functional near-infrared spectroscopy

Assessment of brain function with functional near-infrared spectroscopy (fNIRS) is limited to the outer regions of the cortex. Previously, we demonstrated the feasibility of inferring activity in subcortical "deep brain" regions using cortical functional magnetic resonance imaging (fMRI) and fNIRS activity in healthy adults. Access to subcortical regions subserving emotion and arousal using affordable and portable fNIRS is likely to be transformative for clinical diagnostic and treatment planning. Here, we validate the feasibility of inferring activity in subcortical regions that are central to the pathophysiology of posttraumatic stress disorder (PTSD; i.e. amygdala and hippocampus) using cortical fMRI and simulated fNIRS activity in a sample of adolescents diagnosed with PTSD (N = 20, mean age = 15.3 ± 1.9 years) and age-matched healthy controls (N = 20, mean age = 14.5 ± 2.0 years) as they performed a facial expression task. We tested different prediction models, including linear regression, a multilayer perceptron neural network, and a k-nearest neighbors model. Inference of subcortical fMRI activity with cortical fMRI showed high prediction performance for the amygdala (r > 0.91) and hippocampus (r > 0.95) in both groups. Using fNIRS simulated data, relatively high prediction performance for deep brain regions was maintained in healthy controls (r > 0.79), as well as in youths with PTSD (r > 0.75). The linear regression and neural network models provided the best predictions.

PTSD Symptom dynamics after the great east japan earthquake: mapping the temporal structure using Dynamic Time Warping

Background: After the Great East Japan Earthquake [GEJE], approximately 70,000 Japan Ground Self Defense Force [JGSDF] personnel were deployed, risking Post-Traumatic Stress Disorder [PTSD]. The network approach to psychopathology suggests that symptoms may cause and exacerbate each other, resulting in the emergence and maintenance of disorders, including PTSD. It is therefore important to further explore the temporal interplay between symptoms. Most studies assessing the factor structure of the Impact of Event Scale-Revised [IES-R] have used cross-sectional designs. In this study, the structure of the IES-R was re-evaluated while incorporating the temporal interplay between symptoms.Methods: Using Dynamic Time Warping [DTW] the distances between PTSD symptoms on the IES-R were modelled in 1120 JGSDF personnel. Highly correlated symptoms were clustered at the group level using Distatis three-way principal component analyses of the distance matrices. The resulting clusters were compared to the original three subscales of the IES-R using a Confirmatory Factor Analysis (CFA).Results: The DTW analysis yielded four symptom clusters: Intrusion (five items), Hyperarousal (six items), Avoidance (six items), and Dissociation (five items). CFA yielded better fit estimates for this four-factor solution (RMSEA = 0.084, CFI = 0.918, TLI = 0.906), compared to the original three subscales of the IES-R (RMSEA = 0.103, CFI = 0.873, TLI = 0.858).Conclusions: DTW offers a new method of modelling the temporal relationships between symptoms. It yielded four IES-R symptom clusters, which may facilitate understanding of PTSD as a complex dynamic system.

Functional and structural brain abnormalities in posttraumatic stress disorder: A multimodal meta-analysis of neuroimaging studies

BACKGROUND

Numerous resting-state functional and structural studies have revealed that many brain regions are involved in the pathogenesis of posttraumatic stress disorder (PTSD), but their findings have been inconsistent. Moreover, there has no study explored the functional and structural alterations across languages in PTSD.

METHODS

A meta-analysis of whole-brain on the amplitude of low-frequency fluctuation (ALFF) and voxel-based morphometry (VBM) studies that explored alterations in the spontaneous functional brain activity and grey matter volume (GMV) in PTSD patients across languages by using the Seed-based d Mapping with Permutation of Subject Images (SDM-PSI) software.

RESULTS

A total of 15 studies (19 datasets) comprising 577 PTSD patients and 499 HCs for ALFF, and 27 studies (31 datasets) comprising 539 PTSD patients and 693 HCs for VBM were included. Overall, PTSD patients across languages displayed decreased ALFF in the in the left amygdala. For VBM meta-analysis, PTSD patients across languages displayed reduced GMV in the bilateral anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC), striatum, insula, superior temporal gyrus, left postcentral gyrus, and occipital gyrus.

CONCLUSIONS

The multimodal meta-analysis suggest that PTSD patients showed similar pattern of aberrant resting-state functional brain activity and structure mainly in the amygdala, suggesting that structural deficits might underlie alterations in function. In addition, some regions exhibited only structural abnormalities in PTSD, including the ACC/mPFC, striatum, insula, primary visual, auditory and sensorimotor cortices. Moreover, consistent alterations in PTSD patients across languages may draw attention to the disparity in multi-cultural considerations in psychiatric research and further understanding the neurophysiopathology of PTSD.

Over-representation of fundamental decision variables in the prefrontal cortex underlies decision bias

The brain is organized into anatomically distinct structures consisting of a variety of projection neurons. While such evolutionarily conserved neural circuit organization underlies the innate ability of animals to swiftly adapt to environments, they can cause biased cognition and behavior. Although recent studies have begun to address the causal importance of projection-neuron types as distinct computational units, it remains unclear how projection types are functionally organized in encoding variables during cognitive tasks. This review focuses on the neural computation of decision making in the prefrontal cortex and discusses what decision variables are encoded by single neurons, neuronal populations, and projection type, alongside how specific projection types constrain decision making. We focus particularly on "over-representations" of distinct decision variables in the prefrontal cortex that reflect the biological and subjective significance of the variables for the decision makers. We suggest that task-specific over-representation in the prefrontal cortex involves the refinement of the given decision making, while generalized over-representation of fundamental decision variables is associated with suboptimal decision biases, including pathological ones such as those in patients with psychiatric disorders. Such over-representation of the fundamental decision variables in the prefrontal cortex appear to be tightly constrained by afferent and efferent connections that can be optogenetically intervened on. These ideas may provide critical insights into potential therapeutic targets for psychiatric disorders, including addiction and depression.

Differential relationships of PTSD symptom clusters with cortical thickness and grey matter volumes among women with PTSD

Structural neuroimaging studies of posttraumatic stress disorder (PTSD) have typically reported reduced cortical thickness (CT) and gray matter volume (GMV) in subcortical structures and networks involved in memory retrieval, emotional processing and regulation, and fear acquisition and extinction. Although PTSD is more common in women, and interpersonal violence (IPV) exposure is a more potent risk factor for developing PTSD relative to other forms of trauma, most of the existing literature examined combat-exposed men with PTSD. Vertex-wise CT and subcortical GMV analyses were conducted to examine potential differences in a large, well-characterized sample of women with PTSD stemming from IPV-exposure (n = 99) compared to healthy trauma-free women without a diagnosis of PTSD (n = 22). Subgroup analyses were also conducted to determine whether symptom severity within specific PTSD symptom clusters (e.g., re-experiencing, active avoidance, hyperarousal) predict CT and GMV after controlling for comorbid depression and anxiety. Results indicated that a diagnosis of PTSD in women with IPV-exposure did not significantly predict differences in CT across the cortex or GMV in the amygdala or hippocampus compared to healthy controls. However, within the PTSD group, greater re-experiencing symptom severity was associated with decreased CT in the left inferior and middle temporal gyrus, and decreased CT in the right parahippocampal and medial temporal gyrus. In contrast, greater active avoidance symptom severity was associated with greater CT in the left lateral fissure, postcentral gyrus, and middle/lateral occipital cortex, and greater CT in the right paracentral, posterior cingulate, and superior occipital gyrus. In terms of GMV, greater hyperarousal symptom severity was associated with reduced left amygdala GMV, while greater active avoidance symptom severity was associated with greater right amygdala GMV. These findings suggest that structural brain alterations among women with IPV-related PTSD may be driven by symptom severity within specific symptom clusters and that PTSD symptom clusters may have a differential (increased or decreased) association with brain structures.