Given the subjective nature of conventional diagnostic methods for post-traumatic stress disorder (PTSD), an objectively measurable biomarker is highly desirable; especially to clinicians and ...researchers. Macroscopic neural circuits measured using magnetoencephalography (MEG) has previously been shown to be indicative of the PTSD phenotype and severity. In the present study, we employed a machine learning-based classification framework using MEG neural synchrony to distinguish combat-related PTSD from trauma-exposed controls. Support vector machine (SVM) was used as the core classification algorithm. A recursive random forest feature selection step was directly incorporated in the nested SVM cross validation process (CV-SVM-rRF-FS) for identifying the most important features for PTSD classification. For the five frequency bands tested, the CV-SVM-rRF-FS analysis selected the minimum numbers of edges per frequency that could serve as a PTSD signature and be used as the basis for SVM modelling. Many of the selected edges have been reported previously to be core in PTSD pathophysiology, with frequency-specific patterns also observed. Furthermore, the independent partial least squares discriminant analysis suggested low bias in the machine learning process. The final SVM models built with selected features showed excellent PTSD classification performance (area-under-curve value up to 0.9). Testament to its robustness when distinguishing individuals from a heavily traumatised control group, these developments for a classification model for PTSD also provide a comprehensive machine learning-based computational framework for classifying other mental health challenges using MEG connectome profiles.
Purpose
A dissociative-posttraumatic stress disorder (PTSD) subtype has been included in the DSM-5. However, it is not yet clear whether certain socio-demographic characteristics or ...psychological/clinical constructs such as comorbid psychopathology differentiate between severe PTSD and dissociative-PTSD. The current study investigated the existence of a dissociative-PTSD subtype and explored whether a number of trauma and clinical covariates could differentiate between severe PTSD alone and dissociative-PTSD.
Methods
The current study utilized a sample of 432 treatment seeking Canadian military veterans. Participants were assessed with the Clinician Administered PTSD Scale (CAPS) and self-report measures of traumatic life events, depression, and anxiety. CAPS severity scores were created reflecting the sum of the frequency and intensity items from each of the 17 PTSD and 3 dissociation items. The CAPS severity scores were used as indicators in a latent profile analysis (LPA) to investigate the existence of a dissociative-PTSD subtype. Subsequently, several covariates were added to the model to explore differences between severe PTSD alone and dissociative-PTSD.
Results
The LPA identified five classes: one of which constituted a severe PTSD group (30.5 %), and one of which constituted a dissociative-PTSD group (13.7 %). None of the included, demographic, trauma, or clinical covariates were significantly predictive of membership in the dissociative-PTSD group compared to the severe PTSD group.
Conclusions
In conclusion, a significant proportion of individuals report high levels of dissociation alongside their PTSD, which constitutes a dissociative-PTSD subtype. Further investigation is needed to identify which factors may increase or decrease the likelihood of membership in a dissociative-PTSD subtype group compared to a severe PTSD only group.
Research on the relationship between insomnia and nightmares, and suicidal ideation (SI) has produced variable findings, especially with regard to military samples. This study investigates whether ...depression mediated the relationship between: 1) sleep disturbances and SI, and 2) trauma-related nightmares and SI, in a sample of treatment-seeking Canadian Armed Forces (CAF) personnel and veterans (N = 663).
Regression analyses were used to investigate associations between sleep disturbances or trauma-related nightmares and SI while controlling for depressive symptom severity, posttraumatic stress disorder (PTSD) symptom severity, anxiety symptom severity, and alcohol use severity. Bootstrapped resampling analyses were used to investigate the mediating effect of depression.
Approximately two-thirds of the sample (68%; N = 400) endorsed sleep disturbances and 88% (N = 516) reported experiencing trauma-related nightmares. Although sleep disturbances and trauma-related nightmares were both significantly associated with SI on their own, these relationships were no longer significant when other psychiatric conditions were included in the models. Instead, depressive symptom severity emerged as the only variable significantly associated with SI in both equations. Bootstrap resampling analyses confirmed a significant mediating role of depression for sleep disturbances.
The findings suggest that sleep disturbances and trauma-related nightmares are associated with SI as a function of depressive symptoms in treatment-seeking CAF personnel and veterans. Treating depression in patients who present with sleep difficulties may subsequently help mitigate suicide risk.
•Post-traumatic stress disorder is a debilitating mental health condition.•Post-traumatic stress disorder is particularly prevalent in military personnel.•Diffusion Tensor Imaging allows detection of ...changes in PTSD.•This study provides a window to the pathophysiological response to trauma.
Post-traumatic stress disorder (PTSD) is a debilitating mental health condition that develops in response to exposure to a traumatic event. The purpose of this study was to investigate white matter differences using diffusion tensor imaging (DTI) in trauma exposed military personnel with and without PTSD.
Data were acquired in compliance with the Hospital for Sick Children and Canadian Armed Forces Research Ethics Boards for the following groups: military personnel with PTSD (PTSD, n = 23), trauma exposed military personnel with no PTSD diagnosis (TE, n = 25) and civilian controls (CC, n =13) . All participants were male. DTI was acquired on a Siemens Trio 3T MRI. Maps of Fractional Anisotropy (FA), Mean Diffusivity (MD), Axial Diffusivity (AD), and Radial Diffusivity (RD) were analyzed using Tract-Based Spatial Statistics (TBSS).
In the PTSD and TE groups, FA was significantly greater within the hippocampus, corpus callosum, cingulum, and several associated white matter tracts. Elevated FA was shown to be largely due to reduced RD suggesting a possible structural substrate that underscores neurophysiological connectivity.
This study reinforces previous findings showing differences in DTI metrics within the limbic system in military personnel exposed to trauma with and without PTSD.
Abstract This study examines the association between suicidal ideation and sleep disturbances in a sample of treatment-seeking Canadian Forces members and veterans, after controlling for probable ...posttraumatic stress disorder (PTSD), major depressive disorder (MDD), generalised anxiety disorder (GAD), and alcohol use disorder (AUD). Subjects included members and veterans of Canadian Forces seeking treatment at a hospital-based Operational Stress Injury Clinic ( n =404). Sleep disturbances and nightmares were measured using individual items on the PTSD Checklist – Military Version (PCL – M), while the suicidality item of the Patient Health Questionnaire (PHQ-9) was used as a stand-alone item to assess presence or absence of suicidal ideation. Regression analyses were used to determine the respective impact of (1) insomnia and (2) nightmares on suicidal ideation, while controlling for presence of probable PTSD, MDD, GAD, and AUD. We found that 86.9% of patients reported having problems falling or staying asleep and 67.9% of patients reported being bothered by nightmares related to military-specific traumatic events. Neither sleep disturbances nor nightmares significantly predicted suicidal ideation; instead, probable MDD emerged as the most significant predictor. The clinical implications of these findings and their potential impact on treatment guidelines are discussed.
Military and veteran populations are unique in their trauma exposures, rates of mental illness and comorbidities, and response to treatments. While reviews have suggested that internet-based ...Cognitive Behavioral Therapy (iCBT) can be useful for treating mental health conditions, the extent to which they may be appropriate for military and veteran populations remain unclear. The goals of the current meta-analysis are to: (1) substantiate the effects of iCBT for military and veteran populations, (2) evaluate its effectiveness compared to control conditions, and (3) examine potential factors that may influence their effectiveness.
This review was completed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting and Cochrane review guidelines. The literature search was conducted using PsycInfo, Medline, Embase, and Proquest Dissertation & Theses on June 4, 2021 with no date restriction. Inclusion criteria included studies that: (1) were restricted to adult military or veteran populations, (2) incorporated iCBT as the primary treatment, and (3) evaluated mental health outcomes. Exclusion criteria included: (1) literature reviews, (2) qualitative studies, (3) study protocols, (4) studies that did not include a clinical/analogue population, and (5) studies with no measure of change on outcome variables. Two independent screeners reviewed studies for eligibility. Data was pooled and analyzed using random-effects and mixed-effects models. Study data information were extracted as the main outcomes, including study condition, sample size, and pre- and post-treatment means, standard deviations for all assessed outcomes, and target outcome. Predictor information were also extracted, and included demographics information, the types of outcomes measured, concurrent treatment, dropout rate, format, length, and delivery of intervention.
A total of 20 studies and 91 samples of data were included in the meta-analysis. The pooled effect size showed a small but meaningful effect for iCBT, g = 0.54, SE = 0.04, 95% CI (0.45, 0.62), Z = 12.32, p < .001. These effects were heterogenous across samples, (I
= 87.96), Q(90) = 747.62, p < .001. Predictor analyses found length of intervention and concurrent treatment to influence study variance within sampled studies, p < .05. Evaluation of iCBT on primary outcomes indicated a small but meaningful effect for PTSD and depression, while effects of iCBT on secondary outcomes found similar results with depression, p < .001.
Findings from the meta-analysis lend support for the use of iCBT with military and veteran populations. Conditions under which iCBT may be optimized are discussed.
Military-related posttraumatic stress disorder (PTSD) is a complex diagnosis with non-linear trajectories of coping and recovery. Current approaches to the evaluation of PTSD and treatment ...discontinuation often rely on biomedical models that dichotomize recovery based on symptom thresholds. This approach may not sufficiently capture the complex lived experiences of Veterans and their families. To explore conceptualizations of recovery, we sought perspectives from Veterans and their partners in a pilot study to understand: 1) how Veterans nearing completion of treatment for military-related PTSD and their partners view recovery; and 2) the experience of progressing through treatment towards recovery.
We employed a concurrent mixed methods design. Nine Veterans nearing the end of their treatment at a specialized outpatient mental health clinic completed quantitative self-report tools assessing PTSD and depressive symptom severity, and an individual, semi-structured interview assessing views on their treatment and recovery processes. Veterans' partners participated in a separate interview to capture views of their partners' treatment and recovery processes. Descriptive analyses of self-report symptom severity data were interpreted alongside emergent themes arising from inductive content analysis of qualitative interviews.
While over half of Veterans were considered "recovered" based on quantitative assessments of symptoms, individual reflections of "recovery" were not always aligned with these quantitative assessments. A persistent narrative highlighted by participants was that recovery from military-related PTSD was not viewed as a binary outcome (i.e., recovered vs. not recovered); rather, recovery was seen as a dynamic, non-linear process. Key components of the recovery process identified by participants included a positive therapeutic relationship, social support networks, and a toolkit of adaptive strategies to address PTSD symptoms.
For participants in our study, recovery was seen as the ability to navigate ongoing issues of symptom management, re-engagement with meaningful roles and social networks, and a readiness for discontinuing intensive, specialized mental health treatment. The findings of this study highlight important considerations in balancing the practical utility of symptom severity assessments with a better understanding of the treatment discontinuation-related needs of Veterans with military-related PTSD and their families, which align with a contemporary biopsychosocial approach to recovery.
EPOXI at Comet Hartley 2 A'Hearn, Michael F.; Belton, Michael J. S.; Delamere, W. Alan ...
Science (American Association for the Advancement of Science),
06/2011, Letnik:
332, Številka:
6036
Journal Article
Recenzirano
Understanding how comets work—what drives their activity—is crucial to the use of comets in studying the early solar system. EPOXI (Extrasolar Planet Observation and Deep Impact Extended ...Investigation) flew past comet 103P/Hartley 2, one with an unusually small but very active nucleus, taking both images and spectra. Unlike large, relatively inactive nuclei, this nucleus is outgassing primarily because of CO 2 , which drags chunks of ice out of the nucleus. It also shows substantial differences in the relative abundance of volatiles from various parts of the nucleus.
Abstract
Post-traumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) are highly prevalent and closely related disorders. Affected individuals often exhibit substantially overlapping ...symptomatology – a major challenge for differential diagnosis in both military and civilian contexts. According to our symptom assessment, the PTSD group exhibited comparable levels of concussion symptoms and severity to the mTBI group. An objective and reliable system to uncover the key neural signatures differentiating these disorders would be an important step towards translational and applied clinical use. Here we explore use of MEG (magnetoencephalography)-multivariate statistical learning analysis in identifying the neural features for differential PTSD/mTBI characterisation. Resting state MEG-derived regional neural activity and coherence (or
functional connectivity
) across seven canonical neural oscillation frequencies (delta to high gamma) were used. The selected features were consistent and largely confirmatory with previously established neurophysiological markers for the two disorders. For regional power from theta, alpha and high gamma bands, the amygdala, hippocampus and temporal areas were identified. In line with regional activity, additional connections within the occipital, parietal and temporal regions were selected across a number of frequency bands. This study is the first to employ MEG-derived neural features to reliably and differentially stratify the two disorders in a multi-group context. The features from alpha and beta bands exhibited the best classification performance, even in cases where distinction by concussion symptom profiles alone were extremely difficult. We demonstrate the potential of using ‘invisible’ neural indices of brain functioning to understand and differentiate these debilitating conditions.
Microglia are immune brain cells implicated in stress-related mental illnesses including posttraumatic stress disorder (PTSD). Their role in the pathophysiology of PTSD, and on neurobiological ...systems that regulate stress, is not completely understood. We tested the hypothesis that microglia activation, in fronto-limbic brain regions involved in PTSD, would be elevated in participants with occupation-related PTSD. We also explored the relationship between cortisol and microglia activation. Twenty participants with PTSD and 23 healthy controls (HC) completed positron emission tomography (PET) scanning of the 18-kDa translocator protein (TSPO), a putative biomarker of microglia activation using the probe
FFEPPA, and blood samples for measurement of cortisol.
FFEPPA V
was non-significantly elevated (6.5-30%) in fronto-limbic regions in PTSD participants.
FFEPPA V
was significantly higher in PTSD participants reporting frequent cannabis use compared to PTSD non-users (44%, p = 0.047). Male participants with PTSD (21%, p = 0.094) and a history of early childhood trauma (33%, p = 0.116) had non-significantly higher
FFEPPA V
. Average fronto-limbic
FFEPPA V
was positively related to cortisol (r = 0.530, p = 0.028) in the PTSD group only. Although we did not find a significant abnormality in TSPO binding in PTSD, findings suggest microglial activation might have occurred in a subgroup who reported frequent cannabis use. The relationship between cortisol and TSPO binding suggests a potential link between hypothalamic-pituitary-adrenal-axis dysregulation and central immune response to trauma which warrants further study.
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