Glucocorticoid sensitivity of leukocytes predicts PTSD, depressive and fatigue symptoms after military deployment: A prospective study

Long-term trajectories of depressive symptoms in deployed military personnel: A 10-year prospective study

BACKGROUND

Military missions, especially those involving combat exposure, are associated with an increased risk of depression. Understanding the long-term course of depressive symptoms post-deployment is important to improve decision-making regarding deployment and mental health policies in the military. This study investigates trajectories of depressive symptoms in the Dutch army, exploring the influence of factors such as demographics, early-life trauma, posttraumatic stress disorder (PTSD) symptoms, and deployment stressors.

METHODS

A cohort of 1032 military men and women deployed to Afghanistan (2005-2008) was studied from pre- to 10 years post-deployment. Depressive and PTSD symptoms were assessed using the Symptom CheckList-90 and the Self-Rating Inventory for PTSD. Demographics, early trauma, and deployment experiences were collected at baseline and after deployment, respectively. Latent Class Growth Analysis was used to explore heterogeneity in trajectories of depressive symptoms over time.

RESULTS

Four trajectories were found: resilient (65%), intermediate-stable (20%), symptomatic-chronic (9%), and late-onset-increasing (6%). The resilient group experienced fewer deployment stressors, while the symptomatic-chronic group reported more early life traumas. Trajectories with elevated depressive symptoms consistently demonstrated higher PTSD symptoms.

LIMITATIONS

Potential nonresponse bias and missing information due to the longitudinal design and extensive follow-up times.

CONCLUSIONS

This study identified multiple trajectories of depressive symptoms in military personnel up to 10 years post-deployment, associated with early trauma, deployment stressors, adverse life events and PTSD symptoms. The prevalence of the resilient trajectory suggests a substantial level of resilience among deployed military personnel. These findings provide valuable insights and a foundation for further research.

Basal forebrain cholinergic systems as circuits through which traumatic stress disrupts emotional memory regulation

Contextual and spatial systems facilitate changes in emotional memory regulation brought on by traumatic stress. Cholinergic basal forebrain (chBF) neurons provide input to contextual/spatial systems and although chBF neurons are important for emotional memory, it is unknown how they contribute to the traumatic stress effects on emotional memory. Clusters of chBF neurons that project to the prefrontal cortex (PFC) modulate fear conditioned suppression and passive avoidance, while clusters of chBF neurons that project to the hippocampus (Hipp) and PFC (i.e. cholinergic medial septum and diagonal bands of Broca (chMS/DBB neurons) are critical for fear extinction. Interestingly, neither Hipp nor PFC projecting chMS/DBB neurons are critical for fear extinction. The retrosplenial cortex (RSC) is a contextual/spatial memory system that receives input from chMS/DBB neurons, but whether this chMS/DBB-RSC circuit facilitates traumatic stress effects on emotional memory remain unexplored. Traumatic stress leads to neuroinflammation and the buildup of reactive oxygen species. These two molecular processes may converge to disrupt chBF circuits enhancing the impact of traumatic stress on emotional memory.

To Predict, Prevent, and Manage Post-Traumatic Stress Disorder (PTSD): A Review of Pathophysiology, Treatment, and Biomarkers

Post-traumatic stress disorder (PTSD) can become a chronic and severely disabling condition resulting in a reduced quality of life and increased economic burden. The disorder is directly related to exposure to a traumatic event, e.g., a real or threatened injury, death, or sexual assault. Extensive research has been done on the neurobiological alterations underlying the disorder and its related phenotypes, revealing brain circuit disruption, neurotransmitter dysregulation, and hypothalamic–pituitary–adrenal (HPA) axis dysfunction. Psychotherapy remains the first-line treatment option for PTSD given its good efficacy, although pharmacotherapy can also be used as a stand-alone or in combination with psychotherapy. In order to reduce the prevalence and burden of the disorder, multilevel models of prevention have been developed to detect the disorder as early as possible and to reduce morbidity in those with established diseases. Despite the clinical grounds of diagnosis, attention is increasing to the discovery of reliable biomarkers that can predict susceptibility, aid diagnosis, or monitor treatment. Several potential biomarkers have been linked with pathophysiological changes related to PTSD, encouraging further research to identify actionable targets. This review highlights the current literature regarding the pathophysiology, disease development models, treatment modalities, and preventive models from a public health perspective, and discusses the current state of biomarker research.

Potential peripheral biomarkers associated with the emergence and presence of posttraumatic stress disorder symptomatology: A systematic review

BACKGROUND

Evidence suggests posttraumatic stress disorder (PTSD) involves an interplay between psychological manifestations and biological systems. Biological markers of PTSD could assist in identifying individuals with underlying dysregulation and increased risk; however, accurate and reliable biomarkers are yet to be identified.

METHODS

A systematic review following the PRISMA guidelines was conducted. Databases included EMBASE, MEDLINE, and Cochrane Central. Studies from a comprehensive 2015 review (Schmidt et al., 2015) and English language papers published subsequently (between 2014 and May 2022) were included. Forty-eight studies were eligible.

RESULTS

Alterations in neuroendocrine and immune markers were most commonly associated with PTSD symptoms. Evidence indicates PTSD symptoms are associated with hypothalamic-pituitary-adrenal axis dysfunction as represented by low basal cortisol, a dysregulated immune system, characterized by an elevated pro-inflammatory state, and metabolic dysfunction. However, a considerable number of studies neglected to measure sex or prior trauma, which have the potential to affect the biological outcomes of posttraumatic stress symptoms. Mixed findings are indicative of the complexity and heterogeneity of PTSD and suggest the relationship between allostatic load, biological markers, and PTSD remain largely undefined.

CONCLUSIONS

In addition to prospective research design and long-term follow up, it is imperative future research includes covariates sex, prior trauma, and adverse childhood experiences. Future research should include exploration of biological correlates specific to PTSD symptom domains to determine whether underlying processes differ with symptom expression, in addition to subclinical presentation of posttraumatic stress symptoms, which would allow for greater understanding of biomarkers associated with disorder risk and assist in untangling directionality.

Effects of prenatal exposure to the 1944-45 Dutch famine and glucocorticoid receptor polymorphisms on later life PTSD susceptibility

Background: Exposure to adversity in utero is thought to increase susceptibility to develop posttraumatic stress disorder (PTSD) following later life trauma, due to neurobiological programming effects during critical developmental periods. It remains unknown whether effects of prenatal adversity on PTSD susceptibility are modulated by genetic variations in neurobiological pathways implicated in PTSD susceptibility.Objective: We investigated whether genetic variation in the glucocorticoid receptor (GR) modulated effects of prenatal famine exposure on late adulthood PTSD symptom severity after trauma exposure in childhood and mid-to-late adulthood.Method: We included N = 439 term-born singleton adults (mean age: 72 years, 54.2% women) from the Dutch Famine Birth Cohort, born around the time of the Dutch Famine of 1944/1945, divided into exposure and control groups based on timing of the famine during gestation. Participants filled out self-report questionnaires on childhood (Childhood Trauma Questionnaire) and mid-to-late adulthood (Life Events Checklist for DSM-5) trauma, and current PTSD symptom severity (PTSD Checklist for DSM-5). GR haplotypes were determined from four functional GR single nucleotide polymorphisms (ER22/23EK, N363S, BclI and exon 9β) in previously collected DNA. Linear regression analyses were performed to investigate associations of GR haplotype and prenatal famine exposure in conjunction with later life trauma on PTSD symptom severity.Results: We observed a significant three-way interaction between the GR Bcll haplotype, famine exposure during early gestation, and adulthood trauma exposure on PTSD symptom severity in late adulthood. Only participants exposed to famine during early gestation without the GR Bcll haplotype showed a significantly stronger positive association between adulthood trauma and PTSD symptom severity than non-exposed participants, indicating increased PTSD susceptibility.Conclusions: Our results illustrate the importance of integrated approaches considering genetics and environmental contexts throughout various life periods, including the rarely investigated prenatal environment, to elucidate how PTSD susceptibility evolves throughout life.HIGHLIGHTS Adversity during pregnancy is thought to increase offspring's PTSD risk following later life trauma, but exact neurobiological mechanisms underlying this process remain unknown.We found that effects of prenatal famine exposure on PTSD symptom severity were influenced by genetic variation in the glucocorticoid receptor, which signals effects of the stress hormone cortisol.Integrated approaches considering genetics and environmental contexts throughout both early and later life are important to understand how PTSD risk evolves throughout life.

Trauma-induced human glucocorticoid receptor expression increases predict subsequent HPA-axis blunting in a prospective longitudinal design

One of the hallmarks of post-traumatic stress disorder (PTSD) is abnormalities in the HPA-axis. This includes alterations in its negative feedback regulation. Although altered glucocorticoid receptor (GR) mRNA expression is thought to play a crucial role herein, direct longitudinal evidence in humans is lacking to support this assumption. The current prospective longitudinal study assessed the consequence of repeated trauma exposure on GR mRNA expression from saliva samples in early-career police recruits (n = 112) by assessing them before and after trauma exposure. We did not observe a relationship between change in GR mRNA expression and development of PTSD symptom severity. However, the more traumatic events were experienced during police training the stronger GR mRNA expression was increased. Moreover, increases in GR mRNA expression were associated with blunted HPA-axis stress-reactivity at follow-up compared to baseline. This study provides the first longitudinal evidence of a dose-response relationship between trauma and human GR mRNA expression (extracted from saliva) changes; therefore, replication is warranted. Our finding might contribute a possible explanatory framework for blunted HPA-axis function associated with PTSD.

The Role of Microglia in the (Mal)adaptive Response to Traumatic Experience in an Animal Model of PTSD

The present study investigates whether predator scent-stress (PSS) shifts the microglia from a quiescent to a chronically activated state and whether morphological alterations in microglial activation differ between individuals displaying resilient vs. vulnerable phenotypes. In addition, we examined the role that GC receptors play during PSS exposure in the impairment of microglial activation and thus in behavioral response. Adult male Sprague Dawley rats were exposed to PSS or sham-PSS for 15 min. Behaviors were assessed with the elevated plus-maze (EPM) and acoustic startle response (ASR) paradigms 7 days later. Localized brain expression of Iba-1 was assessed, visualized, and classified based on their morphology and stereological counted. Hydrocortisone and RU486 were administered systemically 10 min post PSS exposure and behavioral responses were measured on day 7 and hippocampal expression of Ionized calcium-binding adaptor molecule 1 (Iba-1) was subsequently evaluated. Animals whose behavior was extremely disrupted (PTSD-phenotype) selectively displayed excessive expression of Iba-1 with concomitant downregulation in the expression of CX3C chemokine receptor 1 (CX3CR1) in hippocampal structures as compared with rats whose behavior was minimally or partially disrupted. Changes in microglial morphology have also been related only to the PTSD-phenotype group. These data indicate that PSS-induced microglia activation in the hippocampus serves as a critical mechanistic link between the HPA-axis and PSS-induced impairment in behavioral responses.

Insomnia, Fatigue, and Depression: Theoretical and Clinical Implications of a Self-reinforcing Feedback Loop in Cancer

Introduction:

Insomnia is emerging as a modifiable major risk factor for mental and physical problems, including cancer, and it may contribute to cancer-related fatigue and depression. Since both fatigue and depression may favor insomnia as well, we may hypothesize a self-reinforcing feedback loop among these factors in cancer.

Methods:

With the aim of discussing this hypothesis, PubMed, PsycINFO, and Embase electronic databases were searched for literature published according to the PRISMA method with several combinations of terms such as “insomnia” and “cancer” and “fatigue” and “depression”. On this basis, we conducted a narrative review about theoretical aspects of insomnia in the context of cancer and about its role in cancer-related fatigue and depression.

Results:

Twenty-one papers were selected according to inclusion/exclusion criteria. Insomnia is frequent in cancer, and it is associated with cancer-related comorbid conditions such as emotional distress, depressive symptoms, and cancer-related fatigue. The hyperactivation of stress and inflammatory systems, which sustain insomnia, may contribute to cancer-related depression and fatigue. A deleterious feedback loop may be created, and it may perpetuate not only insomnia but also these cancer-related comorbid conditions.

Conclusion:

Although the understanding of the causal relationship between insomnia/ depression/fatigue in individuals with cancer is limited, we may hypothesize that these symptoms can exacerbate and maintain each other. When insomnia is established in cancer, it may lead to a vicious cycle with fatigue and depression and may contribute to adverse cancer outcomes. Interventions targeting insomnia could provide a promising approach not only for insomnia but also for cancer-related symptoms among cancer patients.

Asthma and posttraumatic stress disorder (PTSD): Emerging links, potential models and mechanisms

Posttraumatic stress disorder (PTSD) is a highly prevalent, debilitating mental health condition. A better understanding of contributory neurobiological mechanisms will lead to effective treatments, improving quality of life for patients. Given that not all trauma-exposed individuals develop PTSD, identification of pre-trauma susceptibility factors that can modulate posttraumatic outcomes is important. Recent clinical evidence supports a strong link between inflammatory conditions and PTSD. A particularly strong association has been reported between asthma and PTSD prevalence and severity. Unlike many other PTSD-comorbid inflammatory conditions, asthma often develops in children, sensitizing them to subsequent posttraumatic pathology throughout their lifetime. Currently, there is a significant need to understand the neurobiology, shared mechanisms, and inflammatory mediators that may contribute to comorbid asthma and PTSD. Here, we provide a translational perspective of asthma and PTSD risk and comorbidity, focusing on clinical associations, relevant rodent paradigms and potential mechanisms that may translate asthma-associated inflammation to PTSD development.

Pre-deployment risk factors for PTSD in active-duty personnel deployed to Afghanistan: a machine-learning approach for analyzing multivariate predictors

Active-duty Army personnel can be exposed to traumatic warzone events and are at increased risk for developing post-traumatic stress disorder (PTSD) compared with the general population. PTSD is associated with high individual and societal costs, but identification of predictive markers to determine deployment readiness and risk mitigation strategies is not well understood. This prospective longitudinal naturalistic cohort study-the Fort Campbell Cohort study-examined the value of using a large multidimensional dataset collected from soldiers prior to deployment to Afghanistan for predicting post-deployment PTSD status. The dataset consisted of polygenic, epigenetic, metabolomic, endocrine, inflammatory and routine clinical lab markers, computerized neurocognitive testing, and symptom self-reports. The analysis was computed on active-duty Army personnel (N = 473) of the 101st Airborne at Fort Campbell, Kentucky. Machine-learning models predicted provisional PTSD diagnosis 90-180 days post deployment (random forest: AUC = 0.78, 95% CI = 0.67-0.89, sensitivity = 0.78, specificity = 0.71; SVM: AUC = 0.88, 95% CI = 0.78-0.98, sensitivity = 0.89, specificity = 0.79) and longitudinal PTSD symptom trajectories identified with latent growth mixture modeling (random forest: AUC = 0.85, 95% CI = 0.75-0.96, sensitivity = 0.88, specificity = 0.69; SVM: AUC = 0.87, 95% CI = 0.79-0.96, sensitivity = 0.80, specificity = 0.85). Among the highest-ranked predictive features were pre-deployment sleep quality, anxiety, depression, sustained attention, and cognitive flexibility. Blood-based biomarkers including metabolites, epigenomic, immune, inflammatory, and liver function markers complemented the most important predictors. The clinical prediction of post-deployment symptom trajectories and provisional PTSD diagnosis based on pre-deployment data achieved high discriminatory power. The predictive models may be used to determine deployment readiness and to determine novel pre-deployment interventions to mitigate the risk for deployment-related PTSD.

Is PTSD-Phenotype Associated with HPA-Axis Sensitivity? Feedback Inhibition and Other Modulating Factors of Glucocorticoid Signaling Dynamics

Previously, we found that basal corticosterone pulsatility significantly impacts the vulnerability for developing post-traumatic stress disorder (PTSD). Rats that exhibited PTSD-phenotype were characterized by blunted basal corticosterone pulsatility amplitude and a blunted corticosterone response to a stressor. This study sought to identify the mechanisms underlining both the loss of pulsatility and differences in downstream responses. Serial blood samples were collected manually via jugular vein cannula at 10-min intervals to evaluate suppression of corticosterone following methylprednisolone administration. The rats were exposed to predator scent stress (PSS) after 24 h, and behavioral responses were assessed 7 days post-exposure for retrospective classification into behavioral response groups. Brains were harvested for measurements of the glucocorticoid receptor, mineralocorticoid receptor, FK506-binding protein-51 and arginine vasopressin in specific brain regions to assess changes in hypothalamus–pituitary–adrenal axis (HPA) regulating factors. Methylprednisolone produced greater suppression of corticosterone in the PTSD-phenotype group. During the suppression, the PTSD-phenotype rats showed a significantly more pronounced pulsatile activity. In addition, the PTSD-phenotype group showed distinct changes in the ventral and dorsal CA1, dentate gyrus as well as in the paraventricular nucleus and supra-optic nucleus. These results demonstrate a pre-trauma vulnerability state that is characterized by an over-reactivity of the HPA and changes in its regulating factors.

Cortisol awakening response over the course of humanitarian aid deployment: a prospective cohort study

Background: Internationally deployed humanitarian aid (HA) workers are routinely confronted with potentially traumatic stressors. However, it remains unknown whether HA deployment and related traumatic stress are associated with long-term changes in hypothalamic-pituitary-adrenal (HPA) axis function. Therefore, we investigated whether cortisol awakening response (CAR) decreased upon deployment and whether this was moderated by previous and recent trauma exposure and parallel changes in symptom severity and perceived social support. Methods: In this prospective study, n = 86 HA workers (68% females) completed questionnaires regarding trauma exposure, posttraumatic stress disorder (PTSD), anxiety and depressive symptoms and perceived social support, as well as salivary cortisol assessments at awakening and 30 minutes post-awakening at before, early and 3-6 months post-deployment. Results: Linear mixed models showed significantly decreased CAR (b(SE) = -.036(.011), p = .002) and awakening cortisol over time (b(SE) = -.007(.003), p = .014). The extent of awakening cortisol change was significantly moderated by interactions between previous and recent trauma exposure. Also, a steeper awakening cortisol decrease was significantly associated with higher mean anxiety and PTSD symptoms across assessments. No significant effects were found for social support. Conclusions: We observed attenuated CAR and awakening cortisol upon HA deployment, with a dose-response effect between trauma exposure before and during the recent deployment on awakening cortisol. Awakening cortisol change was associated with PTSD and anxiety symptom levels across assessments. Our findings support the need for organizational awareness that work-related exposures may have long-lasting biological effects. Further research assessing symptoms and biological measures in parallel is needed to translate current findings into guidelines on the individual level.

The Pathways between Cortisol-Related Regulation Genes and PTSD Psychotherapy

Post-traumatic stress disorder (PTSD) only develops after exposure to a traumatic event in some individuals. PTSD can be chronic and debilitating, and is associated with co-morbidities such as depression, substance use, and cardiometabolic disorders. One of the most important pathophysiological mechanisms underlying the development of PTSD and its subsequent maintenance is a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis. The corticotrophin-releasing hormone, cortisol, glucocorticoid receptor (GR), and their respective genes are some of the mediators of PTSD's pathophysiology. Several treatments are available, including medication and psychotherapies, although their success rate is limited. Some pharmacological therapies based on the HPA axis are currently being tested in clinical trials and changes in HPA axis biomarkers have been found to occur in response not only to pharmacological treatments, but also to psychotherapy-including the epigenetic modification of the GR gene. Psychotherapies are considered to be the first line treatments for PTSD in some guidelines, even though they are effective for some, but not for all patients with PTSD. This review aims to address how knowledge of the HPA axis-related genetic makeup can inform and predict the outcomes of psychotherapeutic treatments.

The glucocorticoid receptor-FKBP51 complex contributes to fear conditioning and posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) can develop after exposure to severe psychological trauma, leaving patients with disabling anxiety, nightmares, and flashbacks. Current treatments are only partially effective, and development of better treatments is hampered by limited knowledge of molecular mechanisms underlying PTSD. We have discovered that the glucocorticoid receptor (GR) and FK506 binding protein 51 (FKBP51) form a protein complex that is elevated in PTSD patients compared with unaffected control subjects, subjects exposed to trauma without PTSD, and patients with major depressive disorder (MDD). The GR-FKBP51 complex is also elevated in fear-conditioned mice, an aversive learning paradigm that models some aspects of PTSD. Both PTSD patients and fear-conditioned mice had decreased GR phosphorylation, decreased nuclear GR, and lower expression of 14-3-3ε, a gene regulated by GR. We created a peptide that disrupts GR-FKBP51 binding and reverses behavioral and molecular changes induced by fear conditioning. This peptide reduces freezing time and increases GR phosphorylation, GR-FKBP52 binding, GR nuclear translocation, and 14-3-3ε expression in fear-conditioned mice. These experiments demonstrate a molecular mechanism contributing to PTSD and suggest that the GR-FKBP51 complex may be a diagnostic biomarker and a potential therapeutic target for preventing or treating PTSD.

Hair cortisol predicts avoidance behavior and depressiveness after first-time and single-event trauma exposure in motor vehicle crash victims

The role of cortisol as a premorbid vulnerability factor for trauma sequelae remains unclear. Furthermore, the onset of long-term endocrine changes in response to first-time trauma as a function of later psychopathology is not clarified yet. Thus the predictive value of pre- and post-traumatic hair cortisol concentrations (HCCs) for psychological trauma sequelae was investigated in response to motor vehicle crash (MVC). A total of N= 62 MVC survivors participated in this study (46 females, mean age (SD): 43.94(12.95)). Subsequent trauma sequelae were measured with a structured clinical interview and self-report questionnaires to evaluate psychological symptoms (pre-MVC and three months post-MVC). Hair strands were taken immediately after MVC and three months post-MVC, reflecting cumulative cortisol secretion over the three-month period before and after the MVC. A total of 22.6% of the participants developed a trauma sequela with an affective disorder (14.5%) and/or anxiety disorder (16.1%). We observed a significant main effect of group and diagnosis × time interaction with an increase of HCC in those individuals who presented a subsequent psychiatric disorder. Regression analyses revealed that post-MVC increased HCC were significantly predictive of higher levels of subsequent depressiveness, and that pre-MVC increased HCC were predictive of higher levels of subsequent avoidance behavior. Our findings demonstrate that individual differences in long-term cortisol secretion in response to a first-time traumatic event (MVC) contribute to subsequent psychopathology. Specifically, higher long-term cortisol secretion before and after first-time MVC was a risk factor for subsequent development of avoidance behavior and depressiveness, respectively.Lay summaryHigher cortisol secretion and stress experience before a motor vehicle crash was a risk factor for subsequent development of psychological symptoms.

Literature review and methodological considerations for understanding circulating risk biomarkers following trauma exposure

Exposure to traumatic events is common. While many individuals recover following trauma exposure, a substantial subset develop adverse posttraumatic neuropsychiatric sequelae (APNS) such as posttraumatic stress, major depression, and regional or widespread chronic musculoskeletal pain. APNS cause substantial burden to the individual and to society, causing functional impairment and physical disability, risk for suicide, lost workdays, and increased health care costs. Contemporary treatment is limited by an inability to identify individuals at high risk of APNS in the immediate aftermath of trauma, and an inability to identify optimal treatments for individual patients. Our purpose is to provide a comprehensive review describing candidate blood-based biomarkers that may help to identify those at high risk of APNS and/or guide individual intervention decision-making. Such blood-based biomarkers include circulating biological factors such as hormones, proteins, immune molecules, neuropeptides, neurotransmitters, mRNA, and noncoding RNA expression signatures, while we do not review genetic and epigenetic biomarkers due to other recent reviews of this topic. The current state of the literature on circulating risk biomarkers of APNS is summarized, and key considerations and challenges for their discovery and translation are discussed. We also describe the AURORA study, a specific example of current scientific efforts to identify such circulating risk biomarkers and the largest study to date focused on identifying risk and prognostic factors in the aftermath of trauma exposure.

Early posttraumatic autonomic and endocrine markers to predict posttraumatic stress symptoms after a preventive intervention with oxytocin

BACKGROUND

Efficient prevention of posttraumatic stress disorder (PTSD) needs to target individuals with an increased risk for adverse outcome after trauma. Prognostic or prescriptive biological markers assessed early posttrauma may inform personalized treatment recommendations.

OBJECTIVE

To test prognostic and prescriptive effects of early (posttraumatic) autonomic and endocrine markers on PTSD symptom development.

METHOD

Autonomic and endocrine markers were assessed within 12 days posttrauma and before treatment initiation within a randomized placebo-controlled trial investigating repeated oxytocin administration as preventive intervention for PTSD. Linear mixed effects models were used to test the effects of heart rate (variability), resting cortisol, morning cortisol and cortisol awakening response (CAR), cortisol suppression by dexamethasone and resting oxytocin on PTSD symptoms 1.5, 3 and 6 months posttrauma in men (n = 54), women using hormonal contraception (n = 27) and cycling women (n = 19).

RESULTS

We found significant prognostic effects of resting oxytocin and cortisol suppression. In women using hormonal contraception, higher oxytocin was associated with higher PTSD symptoms across follow-up. Stronger cortisol suppression by dexamethasone, reflecting increased glucocorticoid receptor feedback sensitivity, was associated with lower PTSD symptoms across follow-up in men, but with higher symptoms at 1.5 months in women using hormonal contraception. These effects were independent of treatment condition. No further significant prognostic or prescriptive effects were detected.

CONCLUSION

Our exploratory study indicates that resting oxytocin and glucocorticoid receptor feedback sensitivity early posttrauma are associated with subsequent PTSD symptom severity. Notably, prognostic effects depended on sex and hormonal contraception use, emphasizing the necessity to consider these factors in biomedical PTSD research.

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.

Prevalence of Posttraumatic Stress Symptoms and Associated Characteristics Among Patients With Chronic Pain Conditions in a Norwegian University Hospital Outpatient Pain Clinic

Introduction

Comorbid posttraumatic stress disorder (PTSD) in patients with chronic pain may have a negative effect on the course and outcome of both disorders. Nevertheless, the co-occurrence of the two conditions is often overlooked in clinical settings. Further, little is known about how PTSD is associated with biopsychosocial characteristics in this patient group. The first objective was to assess the prevalence of posttraumatic stress symptoms (PTSS) in patients with chronic pain in a Norwegian university hospital outpatient pain clinic. The second objective was to investigate possible associations between PTSS and adverse outcomes such as pain intensity, disability, and distress. The third objective was to compare the PTSS prevalence rates between primary versus secondary pain conditions.

Materials and methods

Six hundred and ninety-two patients meeting for pain assessment completed self-report questionnaires about PTSS and possibly associated factors. The Life Events Checklist and the Stressful Life Events Screening Questionnaire were used to screen for potentially traumatic life events. The Impact of Events Scale - Revised and the PTSD Checklist for DSM-5 were used to assess PTSS. Differences between patients with and without severe PTSS on the possibly associated variables were analyzed by chi-squared-, and t-tests.

Results

20.7% of the participants reported a level of PTSS qualifying for a PTSD diagnosis. These patients reported higher levels of pain intensity, pain bothersomeness, disability, and psychological distress, as well as lower levels of self-efficacy. They also reported higher levels of pain catastrophizing, perceived injustice, fatigue, and sleep difficulties. Finally, there was not a significant difference in prevalence rates between primary and secondary pain conditions.

Discussion

PTSS are frequent in patients with chronic pain, and a range of psychological characteristics is associated with a high level of such symptoms in this patient group. Patients with both conditions report a significantly higher symptom load, and the potential impact on the individual's life is major. In terms of pain condition, there were no differences in PTSS between primary pain conditions and secondary pain conditions in this pain population. This study emphasizes the importance of increased attention on PTSS when seeing patients with chronic pain conditions in clinical practice.

Cohort profile: the Prospective Research In Stress-Related Military Operations (PRISMO) study in the Dutch Armed Forces

PURPOSE

The Prospective Research in Stress-Related Military Operations (PRISMO) study was initiated to gain a better understanding of the long-term impact of military deployment on mental health, and to map the different biological and psychological factors that contribute to the development of stress-related mental health symptoms.

PARTICIPANTS

The PRISMO cohort consists of a convenience sample of Dutch military personnel deployed to Afghanistan between 2005 and 2008. Baseline data collection resulted in the recruitment of 1032 military men and women. Combat troops as well as non-combat support troops were recruited to increase the representativeness of the sample to the population as a whole.

FINDINGS TO DATE

The prevalence of various mental health symptoms increases after deployment in PRISMO cohort members, but symptom progression over time appears to be specific for various mental health symptoms. For post-traumatic stress disorder, we found a short-term symptom increase within 6 months after deployment (8.2%), and a long-term symptom increase at 5 years after deployment (12.9%). Several biological vulnerability factors associated with the development of stress-related conditions after deployment were identified, including predeployment glucocorticoid receptor sensitivity and predeployment testosterone level. Thus far, 34 publications have resulted from the cohort.

FUTURE PLANS

Various analyses are planned that will include the prevalence of mental health symptoms at 10 years postdeployment, as well as trajectory analyses that capture the longitudinal development of symptoms. Furthermore, we will use a machine learning approach to develop predictive and network models for several mental health symptoms, incorporating biological, psychological and social factors.

Reduced Expression of Immune Mediators by T-Cell Subpopulations of Combat-Exposed Veterans With Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) has been suggested to be associated with an inflammatory immune state, although few studies have examined peripheral blood lymphocytes in subjects that have PTSD and compared immune parameters to subjects that experienced similar trauma, but did not develop PTSD. An exploratory approach was undertaken to compare phenotypes of blood CD4⁺ and CD8⁺ subpopulations and their expression of immune mediators between Veterans of the Iraq and Afghanistan wars who experienced similar levels of combat, with some developing PTSD and other not. The results of this study did not demonstrate evidence of enhanced immune activation of peripheral blood lymphocytes. Instead, the results showed a decline in expression of the pro-inflammatory mediator IFN-γ and the cytotoxin granzyme B in CD8⁺ subpopulations from Veterans with PTSD. While the reductions in expression of IFN-γ and granzyme B did not reach statistical significance when examining the CD8⁺ cell population as a whole, the declines were significant when examining the CD8⁺ cell subpopulations, with different mediators being reduced in different subpopulations. The most prominent decline in IFN-γ expression was by the unconventional CD8^dimCD3⁺ T-cell subpopulation that has been associated with chronic infection and immune fatigue. The decline in granzyme B was most prominent in the NK-containing CD8^dimCD3^- subpopulation of Tcells. Consequently, analysis of blood leukocyte subpopulations, rather than bulk lymphocyte groups, reveals a dampened level of immune reactivity in combat-exposed Veterans with PTSD compared to combat-exposed Veterans without PTSD.

Genetic Model to Study the Co-Morbid Phenotypes of Increased Alcohol Intake and Prior Stress-Induced Enhanced Fear Memory

Posttraumatic Stress Disorder (PTSD) is a complex illness, frequently co-morbid with depression, caused by both genetics, and the environment. Alcohol Use Disorder (AUD), which also co-occurs with depression, is often co-morbid with PTSD. To date, very few genes have been identified for PTSD and even less for PTSD comorbidity with AUD, likely because of the phenotypic heterogeneity seen in humans, combined with each gene playing a relatively small role in disease predisposition. In the current study, we investigated whether a genetic model of depression-like behavior, further developed from the depression model Wistar Kyoto (WKY) rat, is a suitable vehicle to uncover the genetics of co-morbidity between PTSD and AUD. The by-now inbred WKY More Immobile (WMI) and the WKY Less Immobile (WLI) rats were generated from the WKY via bidirectional selective breeding using the forced swim test, a measure of despair-like behavior, as the functional selector. The colonies of the WMIs that show despair-like behavior and the control strain showing less or no despair-like behavior, the WLI, are maintained with strict inbreeding over 40 generations to date. WMIs of both sexes intrinsically self-administer more alcohol than WLIs. Alcohol self-administration is increased in the WMIs without sucrose fading, water deprivation or any prior stress, mimicking the increased voluntary alcohol-consumption of subjects with AUD. Prior Stress-Enhanced Fear Learning (SEFL) is a model of PTSD. WMI males, but not females, show increased SEFL after acute restraint stress in the context-dependent fear conditioning paradigm, a sexually dimorphic pattern similar to human data. Plasma corticosterone differences between stressed and not-stressed WLI and WMI male and female animals immediately prior to fear conditioning predict SEFL results. These data demonstrate that the WMI male and its genetically close, but behaviorally divergent control the WLI male, would be suitable for investigating the underlying genetic basis of comorbidity between SEFL and alcohol self-administration.

Molecular and cellular studies of PTSD: Postmortem transcriptome analysis and novel therapeutic targets

The neurobiology of fear memory and extinction has been the subject of extensive research efforts that have increased our understanding of the brain regions, circuitry, and the cellular and molecular determinants of fear memory processes. However, the inability to access and directly study the brains of PTSD patients has made it difficult to translate the rodent fear memory studies to understand the neurobiological underpinnings of PTSD. The formation of a PTSD brain repository has recently been undertaken to address this issue. This will allow for high throughput gene expression and proteome analysis that can be coupled with epigenetic and genomic approaches to characterize the molecular alterations underlying PTSD. Preliminary studies using next generation RNA sequencing have identified PTSD specific gene expression alterations in the prefrontal cortex (PFC). The approaches used for transcriptome analysis and early findings regarding two glucocorticoid regulated genes of interest, FKBP5 and SGK1 are discussed, and the consequences of altered SGK1 are presented. Altered SGK1 could contribute to synaptic alterations in PFC subregions that could contribute to loss of inhibitory control and extinction of fear memories. Based on these findings, we discuss new studies demonstrating that ketamine can increase synapse number in the PFC and enhance the extinction of fear memory in rodent models and improve symptoms in PTSD patients. Continued molecular and cellular characterization of postmortem brain tissue of PTSD subjects will further define the neurobiology of PTSD and identify novel targets for safe and more efficacious treatments.

Transcriptome Alterations in Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a debilitating psychiatric disorder with a lifetime prevalence of nearly 8% in the general population. While the underlying molecular and cellular mechanisms of PTSD remain unknown, recent studies indicate that PTSD is associated with aberrant gene expression in brain as well as peripheral blood cells. The advent of next-generation sequencing technologies will allow us to elucidate the gene expression changes occurring in both brain and blood of patients with PTSD. RNA sequencing allows for analysis of the amount of transcript being made as well as alternative splicing, novel transcript identification, microRNA, and noncoding RNA quantification. Here we provide an overview of the different types of transcriptomic technologies as well as the gene expression studies performed in human peripheral blood and animal models of PTSD, and review the human PTSD postmortem brain gene profiling studies performed to date.

Inflammation Relates to Chronic Behavioral and Neurological Symptoms in Military Personnel with Traumatic Brain Injuries

Studies have shown that the presence of acute inflammation during recovery is indicative of poor outcomes after a traumatic brain injury (TBI); however, the role of chronic inflammation in predicting post-TBI-related symptoms remains poorly understood. The purpose of this study was to compare inflammatory biomarkers (tumor necrosis factor [TNF]-α, interleukin [IL]-6, and IL-10) in active duty personnel who either sustained or did not sustain a TBI. Service members were also assessed for post-traumatic stress disorder (PTSD), depression, and quality of life through self-reported measures. IL-6 and TNF-α concentrations were greater in the TBI group than in the control group. Of those with a TBI, IL-6 and TNF-α concentrations were greater in the high-PTSD group than the low-PTSD group. No significant differences were found in IL-10 or the IL-6/IL-10 ratios between those with low and high PTSD. Exploratory factor analysis was conducted to describe the latent structure of variables relating to emotional and physical health (i.e., Short Form 36 subcomponents, etc.) and their relationships within the TBI group with inflammatory cytokines. Four symptom profiles were found, with the third component most relating to PTSD and depression symptoms and high inflammation. This study indicates that the comorbidity of TBI and PTSD is associated with inflammation in a military sample, emphasizing the necessity for intervention in order to mitigate the risks associated with inflammation.

How to measure glucocorticoid receptor's sensitivity in patients with stress-related psychiatric disorders

Stress is a state of derailed homeostasis and a main environmental risk factor for psychiatric diseases. Chronic or uncontrollable stress may lead to a dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which is a common feature of stress-related psychiatric disorders. One of the key mechanisms underlying a disturbed HPA axis is an impaired function of the glucocorticoid receptor (GR) with an enhanced or reduced feedback sensitivity for glucocorticoids and subsequently altered concentrations of peripheral cortisol. GR function is regulated by a multiprotein complex including the different expression of the hsp90 co-chaperone FK 506 binding protein 51 (FKBP5) that may be genetically determined or acquired in response to stressful stimuli. Specific patterns of a dysregulation of the HPA axis and GR function are found in different stress-related psychiatric entities e.g. major depression, job-related exhaustion or posttraumatic stress disorder. GR challenge tests like the dexamethasone-suppression test (DST), the dexamethasone-corticotropin-releasing hormone (dex-CRH) test or most recently the analysis of the dexamethasone-induced gene expression are employed to sensitively measure HPA axis activity in these disorders. They provide information for a stratification of phenotypic similar but neurobiological diverse psychiatric disorders. In this review we present a synopsis of GR challenge tests with a focus on the application of the DST, the CRH test and the dex-CRH test as well as the dexamethasone-induced gene expression in stress-related psychiatric entities.

Recent Genetics and Epigenetics Approaches to PTSD

PURPOSE OF REVIEW

Following a life-threatening traumatic exposure, about 10% of those exposed are at considerable risk for developing posttraumatic stress disorder (PTSD), a severe and disabling syndrome characterized by uncontrollable intrusive memories, nightmares, avoidance behaviors, and hyperarousal in addition to impaired cognition and negative emotion symptoms. This review will explore recent genetic and epigenetic approaches to PTSD that explain some of the differential risk following trauma exposure.

RECENT FINDINGS

A substantial portion of the variance explaining differential risk responses to trauma exposure may be explained by differential inherited and acquired genetic and epigenetic risk. This biological risk is complemented by alterations in the functional regulation of genes via environmentally induced epigenetic changes, including prior childhood and adult trauma exposure. This review will cover recent findings from large-scale genome-wide association studies as well as newer epigenome-wide studies. We will also discuss future "phenome-wide" studies utilizing electronic medical records as well as targeted genetic studies focusing on mechanistic ways in which specific genetic or epigenetic alterations regulate the biological risk for PTSD.

A Clinician's Guide to PTSD Biomarkers and Their Potential Future Use

No clinically validated biomarkers have yet been found to assist in the diagnosis and treatment of posttraumatic stress disorder (PTSD). Innovation in clinical trial design, however, has led to the study of biomarkers as part of testing new medications and psychotherapies. There may soon be viable biomarkers to assist in diagnosis of PTSD and prediction of illness trajectory, severity, and functional outcomes; subtyping; and treatment selection. Processes for the identification and validation of biomarker findings are complex, involving several stages of clinical testing before use. The authors provide an overview of issues regarding the clinical use of PTSD biomarkers and examine a set of genetic, epigenetic, and other blood-based markers along with physiological markers currently proposed as candidate tests for PTSD. Studies that have identified candidate biomarkers with relevance to treatment selection in PTSD are discussed as a promising area of research that may lead to changes in clinical practice.

Biological stress indicators as risk markers for increased alcohol use following traumatic experiences

Alcohol misuse is a common sequela of traumatic event experiences causing considerable morbidity and mortality. Although biological stress indicators have been identified as useful risk markers for the development of trauma-related disorders, no such biological indicators exist for the risk of increased alcohol use after trauma exposure. This is the first study to prospectively investigate the predictive value of long-term cortisol levels and acute stress reactivity for the risk of increased alcohol use following traumatic events. Male soldiers were examined before and 12 months following deployment using a standardized diagnostic interview. We analyzed the moderating role of baseline hair cortisol concentrations (HCCs, n = 153) as well as baseline salivary cortisol and alpha-amylase stress reactivity in response to a laboratory stressor (n = 145) in the association between new-onset traumatic events (according to the DSM-IV A1 criterion) and subsequent daily alcohol use. No main effects of pre-traumatic HCC or salivary stress markers on subsequent change in alcohol use were observed. However, we found that with decreasing HCC, the number of new-onset traumatic events was more strongly associated with subsequent alcohol use independent from changes in posttraumatic stress disorder symptoms. No such relation was seen for the acute stress reactivity data. Taken together, this study provides first evidence suggesting that individual differences in long-term cortisol regulation are involved in the association between traumatic experiences and subsequent alcohol use. HCC may thus serve as a potential target in the early identification of individuals vulnerable for increased alcohol use following traumatic events.

Assessing the serum concentration levels of NT-4/5, GPX-1, TNF-α, and l-arginine as biomediators of depression severity in first depressive episode patients with and without posttraumatic stress disorder

BACKGROUND

Neurotrophin-4/5 (NT-4/5) and glutathione peroxidase-1 (GPX-1) have been shown to play a major role in neuronal processes including depression and posttraumatic stress disorder (PTSD). They protect the body from oxidative damage by affecting neuronal growth, development and plasticity. The aim of the study was to evaluate the concentrations of NT-4/5, GPX-1, tumor necrosis factor-α (TNF-α), and l-arginine in patients suffering from varying levels of depression severity, PTSD, and depression comorbid with PTSD.

METHODS

The study involved 460 participants, 360 of whom were diagnosed with different types of depressive episodes. They included: 60 patients with mild depression (MD), 60 patients with moderate depression (MOD), 60 patients with severe depression (SeD), 60 patients with MD and PTSD (MD+PTSD), 60 patients with MOD and PTSD (MOD+PTSD), 60 patients with SeD and PTSD (SeD+PTSD), and 60 patients with PTSD alone. Each group of 60 subjects comprised 30 females and 30 males. The control group comprised 40 subjects. The 10th revision of the International Statistical Classification of Diseases and Related Health Problems was utilized to diagnose depression and PTSD. At 7a.m. blood samples were collected and serum NT-4/5, GPX-1, TNF-α and l-arginine concentrations were assessed using the ELISA method.

RESULTS

Depressive episodes with and without PTSD and PTSD alone became more severe as the levels of TNF-α, l-arginine increased and the levels of NT-4/5, GPX-1 decreased.

CONCLUSION

l-arginine, TNF-α, NT-4/5 and GPX-1 can be markers of depression severity in both males and females with first depressive episode with or without posttraumatic stress disorder.

Health and well-being management in the military: a systematic review of genetic studies

BACKGROUND

Genetic research may have therapeutic value for mental and physical disorders and could have an indicative or preventative capacity. Little is known about the extent, form and utility of military-specific genetic research.

METHOD

A systematic review was conducted to evaluate existing genetic well-being studies of service personnel. The review specifically aimed to ascertain the current state of knowledge and feasibility of using genetics to aid recruitment and health management within military populations. Databases searched included MEDLINE, Embase, PsycINFO and Web of Science for relevant studies. Papers were rated using a genetics-specific quality assessment framework.

RESULTS

Ten papers were included within the final review, with seven mental-health-focused and three physical-health-focused genetic studies found within military populations. Eight papers considered candidate genes, one gene expression and one study was an outline of a future study of significant interest. Genetic commonalties were derived to yield shared physiological pathways. The 10 reviewed papers revealed moderate quality based on quality assessment.

CONCLUSIONS

Current genetic research within military populations is limited. Further studies on genetics, cost effectiveness, ethics and continual monitoring need to be explored before considering any movement toward clinical translation.

Longitudinal changes in glucocorticoid receptor exon 1F methylation and psychopathology after military deployment

Several cross-sectional studies have demonstrated the relevance of DNA methylation of the glucocorticoid receptor exon 1_F region (GR-1_F) for trauma-related psychopathology. We conducted a longitudinal study to examine GR-1_F methylation changes over time in relation to trauma exposure and the development of post-deployment psychopathology. GR-1_F methylation (52 loci) was quantified using pyrosequencing in whole blood of 92 military men 1 month before and 6 months after a 4-month deployment period to Afghanistan. GR-1_F methylation overall (mean methylation and the number of methylated loci) and functional methylation (methylation at loci associated with GR exon 1_F expression) measures were examined. We first investigated the effect of exposure to potentially traumatic events during deployment on these measures. Subsequently, changes in GR-1_F methylation were related to changes in mental health problems (total Symptom Checklist-90 score) and posttraumatic stress disorder (PTSD) symptoms (Self-Report Inventory for PTSD). Trauma exposure during deployment was associated with an increase in all methylation measures, but development of mental health problems 6 months after deployment was only significantly associated with an increased functional methylation. Emergence of post-deployment PTSD symptoms was not related to increased functional methylation over time. Pre-deployment methylation levels did not predict post-deployment psychopathology. To our knowledge, this is the first study to prospectively demonstrate trauma-related increases in GR-1_F methylation, and it shows that only increases at specific functionally relevant sites predispose for post-deployment psychopathology.

Immune signaling mechanisms of PTSD risk and symptom development: insights from animal models

Post-traumatic stress disorder (PTSD) is characterized by persistent re-experiencing of a traumatic event, avoidance, and increased arousal. The approved pharmacological treatments for PTSD have limited efficacy (~60% treatment response), supporting the need for identification of biomarkers and novel pharmacological therapies. Mounting evidence suggests increased inflammatory markers and altered immune gene expression correlate with the severity of symptoms in PTSD patients. However a causal role of immune signaling in development and maintenance of PTSD symptoms is not clear, as inflammation may also be an epiphenomenon related to metabolic and behavioral effects of stress. Animal studies have been critical in understanding the potential causal role of immune signaling in PTSD. In this review we will present the most recent evidence, primarily focusing on the last 3 years, for inflammatory dysfunction both preceding and following PTSD, and how animal models of PTSD have contributed to our understanding of immune mechanisms involved in enduring anxiety after trauma. We will particularly focus on the role of peripheral vs. central immune signaling, the differences between single vs. chronic stress models of PTSD and recent utilization of these models to investigate novel anti-inflammatory treatments. We also highlight some current gaps in the literature including models of TBI/PTSD comorbidity, lack of translational peripheral markers of inflammation and the relatively incomplete understanding of the inflammatory trajectory after severe stress.

Neuroendocrine and neuroimmune markers in PTSD: pre-, peri- and post-trauma glucocorticoid and inflammatory dysregulation

We review current knowledge on how posttraumatic stress disorder (PTSD) is associated with dysregulation of the most commonly studied markers of the endocrine and immune systems pre-, peri- and post-trauma. Lower basal cortisol output, enhanced glucocorticoid receptor function, and a proinflammatory state have been most consistently found in PTSD, with considerable variability among studies and participants. Longitudinal research is scarce, but there is converging evidence that biological dysregulation is present before PTSD onset. Biological dysregulation may become more apparent with increasing time since trauma, and may be reversible with and predict effective treatment. However, considering the variability of findings and the complex interplay of these systems with other factors, the current clinical application of these findings remains limited.

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.

An integrative model linking traumatization, cortisol dysregulation and posttraumatic stress disorder: Insight from recent hair cortisol findings

Abundant evidence suggests links between trauma exposure, altered secretion of the glucocorticoid cortisol and the development/maintenance of posttraumatic stress disorder (PTSD), albeit with some inconsistency in findings. Further insight into the complex relations underlying this process may be derived from an increasing number of studies using hair cortisol analysis, a novel assessment strategy assumed to retrospectively capture long-term integrated cortisol secretion. Here, we evaluate the utility of hair cortisol analysis as a method in trauma/PTSD research and review current findings in this context. We compare hair cortisol data on the complex links between trauma, cortisol dysregulation and PTSD against the main findings obtained using traditional cortisol assessment methods. Finally, we integrate these data into a model which proposes that traumatization leads to dose and time-dependent changes in long-term cortisol output (initial post-traumatic increase, subsequent chronic attenuation) and that such dysregulation may partly mediate the link between traumatic load and the risk of PTSD development upon additional trauma exposure ("building block effect").

Glucocorticoid mediated regulation of inflammation in human monocytes is associated with depressive mood and obesity

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is observed in various conditions, including depression and obesity, which are also often related. Glucocorticoid (GC) resistance and desensitization of peripheral GC receptors (GRs) are often the case in HPA dysregulation seen in depression, and GC plays a critical role in regulation of inflammation. Given the growing evidence that inflammation is a central feature of some depression cases and obesity, we aimed to investigate the immune-regulatory role of GC-GR in relation to depressive mood and obesity in 35 healthy men and women. Depressive mood and level of obesity were assessed, using Beck Depression Inventory (BDI-Ia) and body mass index (BMI), respectively. We measured plasma cortisol levels via enzyme-linked immunosorbent assay and lipopolysaccharide-stimulated intracellular tumor necrosis factor (TNF) production by monocytes, using flow cytometry. Cortisol sensitivity was determined by the difference in monocytic TNF production between the conditions of 1 and 0 μM cortisol incubation ("cortisol-mediated inflammation regulation, CoMIR"). GR vs. mineralocorticoid receptor (MR) antagonism for CoMIR was examined by using mifepristone and spironolactone. A series of multiple regression analyses were performed to investigate independent contribution of depressive mood vs. obesity after controlling for age, gender, systolic blood pressure (SBP), and plasma cortisol in predicting CoMIR. CoMIR was explained by somatic subcomponents of depressive mood (BDI-S: β=-0.499, p=0.001), or BMI (β=-0.466, p<0.01) in separate models. The effects of BMI disappeared when BDI-S was controlled for in the model, while BDI-S remained a significant independent predictor for CoMIR (β=-0.369, p<0.05). However, BMI remained the only independent predictor when BDI-T or BDI-C were controlled for in the model. Mediation analyses also revealed that the relationship between BMI and CoMIR was mediated by BDI-S. The exploratory findings of the relative GR vs. MR roles in CoMIR, using GR and MR blockers, indicated that CoMIR in our cellular model was predominantly mediated by GRs at the higher cortisol dose (1 μM). There was initial indication that greater obesity and somatic depressive symptoms were associated with smaller efficacy of the blockers, which warrants further investigation. Our findings, although in a preclinical sample, signify the shared pathophysiology of immune dysregulation in depression and obesity and warrant further mechanistic investigation.

Altered gene expression of the innate immune, neuroendocrine, and nuclear factor-kappa B (NF-κB) systems is associated with posttraumatic stress disorder in military personnel

Whole transcriptome analysis provides an unbiased examination of biological activity, and likely, unique insight into the mechanisms underlying posttraumatic stress disorder (PTSD) and comorbid depression and traumatic brain injury. This study compared gene-expression profiles in military personnel with PTSD (n=28) and matched controls without PTSD (n=27) using HG-U133 Plus 2.0 microarrays (Affymetrix), which contain 54,675 probe sets representing more than 38,500 genes. Analysis of expression profiles revealed 203 differentially expressed genes in PTSD, of which 72% were upregulated. Using Partek Genomics Suite 6.6, differentially expressed transcription clusters were filtered based on a selection criterion of ≥1.5 relative fold change at a false discovery rate of ≤5%. Ingenuity Pathway Analysis (Qiagen) of the differentially expressed genes indicated a dysregulation of genes associated with the innate immune, neuroendocrine, and NF-κB systems. These findings provide novel insights that may lead to new pharmaceutical agents for PTSD treatments and help mitigate mental and physical comorbidity risk.

Gene networks specific for innate immunity define post-traumatic stress disorder

The molecular factors involved in the development of Post-Traumatic Stress Disorder (PTSD) remain poorly understood. Previous transcriptomic studies investigating the mechanisms of PTSD apply targeted approaches to identify individual genes under a cross-sectional framework lack a holistic view of the behaviours and properties of these genes at the system-level. Here we sought to apply an unsupervised gene-network based approach to a prospective experimental design using whole-transcriptome RNA-Seq gene expression from peripheral blood leukocytes of U.S. Marines (N=188), obtained both pre- and post-deployment to conflict zones. We identified discrete groups of co-regulated genes (i.e., co-expression modules) and tested them for association to PTSD. We identified one module at both pre- and post-deployment containing putative causal signatures for PTSD development displaying an over-expression of genes enriched for functions of innate-immune response and interferon signalling (Type-I and Type-II). Importantly, these results were replicated in a second non-overlapping independent dataset of U.S. Marines (N=96), further outlining the role of innate immune and interferon signalling genes within co-expression modules to explain at least part of the causal pathophysiology for PTSD development. A second module, consequential of trauma exposure, contained PTSD resiliency signatures and an over-expression of genes involved in hemostasis and wound responsiveness suggesting that chronic levels of stress impair proper wound healing during/after exposure to the battlefield while highlighting the role of the hemostatic system as a clinical indicator of chronic-based stress. These findings provide novel insights for early preventative measures and advanced PTSD detection, which may lead to interventions that delay or perhaps abrogate the development of PTSD.

Hair cortisol concentrations and cortisol stress reactivity predict PTSD symptom increase after trauma exposure during military deployment

BACKGROUND

Previous evidence on endocrine risk markers for posttraumatic stress disorder (PTSD) has been inconclusive. Here, we report results of the first prospective study to investigate whether long-term hair cortisol levels and experimentally-induced cortisol stress reactivity are predictive of the development of PTSD symptomatology in response to trauma during military deployment.

METHODS

Male soldiers were examined before deployment to Afghanistan and at a 12-month post-deployment follow-up using dimensional measures for psychopathological symptoms. The predictive value of baseline (i) hair cortisol concentrations (HCC, N=90) and (ii) salivary cortisol stress reactivity (measured by the Trier Social Stress Test, N=80) for the development of PTSD symptomatology after being exposed to new-onset traumatic events was analyzed.

RESULTS

Baseline cortisol activity significantly predicted PTSD symptom change from baseline to follow-up upon trauma exposure. Specifically, our results consistently revealed that lower HCC and lower cortisol stress reactivity were predictive of a greater increase in PTSD symptomatology in soldiers who had experienced new-onset traumatic events (explaining 5% and 10.3% of variance, respectively). Longitudinal analyses revealed an increase in HCC from baseline to follow-up and a trend for a negative relationship between HCC changes and the number of new-onset traumatic events. Additional pre-deployment analyses revealed that trauma history was reflected in lower HCC (at trend level) and that HCC were negatively related to stressful load.

CONCLUSIONS

Our data indicate that attenuated cortisol secretion is a risk marker for subsequent development of PTSD symptomatology upon trauma exposure. Future studies are needed to confirm our findings in other samples.

Blood-based gene-expression biomarkers of post-traumatic stress disorder among deployed marines: A pilot study

The etiology of post-traumatic stress disorder (PTSD) likely involves the interaction of numerous genes and environmental factors. Similarly, gene-expression levels in peripheral blood are influenced by both genes and environment, and expression levels of many genes show good correspondence between peripheral blood and brain tissues. In that context, this pilot study sought to test the following hypotheses: (1) post-trauma expression levels of a gene subset in peripheral blood would differ between Marines with and without PTSD; (2) a diagnostic biomarker panel of PTSD among high-risk individuals could be developed based on gene-expression in readily assessable peripheral blood cells; and (3) a diagnostic panel based on expression of individual exons would surpass the accuracy of a model based on expression of full-length gene transcripts. Gene-expression levels in peripheral blood samples from 50 U.S. Marines (25 PTSD cases and 25 non-PTSD comparison subjects) were determined by microarray following their return from deployment to war-zones in Iraq or Afghanistan. The original sample was carved into training and test subsets for construction of support vector machine classifiers. The panel of peripheral blood biomarkers achieved 80% prediction accuracy in the test subset based on the expression of just two full-length transcripts (GSTM1 and GSTM2). A biomarker panel based on 20 exons attained an improved 90% accuracy in the test subset. Though further refinement and replication of these biomarker profiles are required, these preliminary results provide proof-of-principle for the diagnostic utility of blood-based mRNA-expression in PTSD among trauma-exposed individuals.

Searching for non-genetic molecular and imaging PTSD risk and resilience markers: Systematic review of literature and design of the German Armed Forces PTSD biomarker study

Biomarkers allowing the identification of individuals with an above average vulnerability or resilience for posttraumatic stress disorder (PTSD) would especially serve populations at high risk for trauma exposure like firefighters, police officers and combat soldiers. Aiming to identify the most promising putative PTSD vulnerability markers, we conducted the first systematic review on potential imaging and non-genetic molecular markers for PTSD risk and resilience. Following the PRISMA guidelines, we systematically screened the PubMed database for prospective longitudinal clinical studies and twin studies reporting on pre-trauma and post-trauma PTSD risk and resilience biomarkers. Using 25 different combinations of search terms, we retrieved 8151 articles of which we finally included and evaluated 9 imaging and 27 molecular studies. In addition, we briefly illustrate the design of the ongoing prospective German Armed Forces (Bundeswehr) PTSD biomarker study (Bw-BioPTSD) which not only aims to validate these previous findings but also to identify novel and clinically applicable molecular, psychological and imaging risk, resilience and disease markers for deployment-related psychopathology in a cohort of German soldiers who served in Afghanistan.

Cytokine production as a putative biological mechanism underlying stress sensitization in high combat exposed soldiers

OBJECTIVE

Combat stress exposed soldiers may respond to post-deployment stressful life events (SLE) with increases in symptoms of posttraumatic stress disorder (PTSD), consistent with a model of stress sensitization. Several lines of research point to sensitization as a model to describe the relations between exposure to traumatic events, subsequent SLE, and symptoms of PTSD. Based on previous findings we hypothesized that immune activation, measured as a high in vitro capacity of leukocytes to produce cytokines upon stimulation, underlies stress sensitization.

METHODS

We assessed mitogen-induced cytokine production at 1 month, SLE at 1 year, and PTSD symptoms from 1 month up to 2 years post-deployment in soldiers returned from deployment to Afghanistan (N=693). Exploratory structural equation modeling as well as latent growth models were applied.

RESULTS

The data demonstrated significant three-way interaction effects of combat stress exposure, cytokine production, and post-deployment SLE on linear change in PTSD symptoms over the first 2 years following return from deployment. In soldiers reporting high combat stress exposure, both high mitogen-stimulated T-cell cytokine production and high innate cytokine production were associated with increases in PTSD symptoms in response to post-deployment SLE. In low combat stress exposed soldiers as well as those with low cytokine production, post-deployment SLE were not associated with increases in PTSD symptoms.

CONCLUSION

High stimulated T-cell and innate cytokine production may contribute to stress sensitization in recently deployed, high combat stress exposed soldiers. These findings suggest that detecting and eventually normalizing immune activation may potentially complement future strategies to prevent progression of PTSD symptoms following return from deployment.

Pre-deployment differences in glucocorticoid sensitivity of leukocytes in soldiers developing symptoms of PTSD, depression or fatigue persist after return from military deployment

Deployed soldiers are at risk of developing stress-related conditions, including posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and severe fatigue. We previously observed condition- and cell-specific differences in sensitivity of immune cells for regulation by glucocorticoids (GCs) pre-deployment between male soldiers with and without subsequent development of high levels of these stress-related symptoms. Here we investigated whether these pre-deployment dysregulations in GC-sensitivity of immune cells persisted after return from military deployment. In a prospective, longitudinal study including 721 male and female soldiers, the in vitro GC-sensitivity of monocytes and T-cells was assessed prior to deployment and one and six months post-deployment. Differences in the longitudinal course of sensitivity for regulation by dexamethasone (DEX) of LPS-stimulated TNF-α production and PHA-stimulated T-cell proliferation between soldiers with and without subsequent symptom development were investigated using linear mixed models. Within the whole group, DEX-sensitivity of monocytes was significantly decreased at six months post-deployment compared to the assessments pre-deployment and one month post-deployment. The DEX-sensitivity of T-cells did not significantly change over time. Participants developing high levels of PTSD symptoms showed high DEX-sensitivity of T-cells, while participants developing high levels of depressive symptoms showed low DEX-sensitivity of T-cells before deployment that persisted at the two time points after return. In addition, participants developing severe fatigue had low DEX-sensitivity of monocytes at all assessments. Our finding that the previously observed pre-deployment group differences in peripheral GC-sensitivity persisted until at least six months after return indicates that in vitro GC-sensitivity of T-cells and monocytes may represent a persistent biological vulnerability factor for development of stress-related conditions PTSD, depression and fatigue.