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

Hypothalamic-pituitary-adrenocortical axis: neuropsychiatric aspects

Evidence of aberrant hypothalamic-pituitary-adrenocortical (HPA) activity in many psychiatric disorders, although not universal, has sparked long-standing interest in HPA hormones as biomarkers of disease or treatment response. HPA activity may be chronically elevated in melancholic depression, panic disorder, obsessive-compulsive disorder, and schizophrenia. The HPA axis may be more reactive to stress in social anxiety disorder and autism spectrum disorders. In contrast, HPA activity is more likely to be low in PTSD and atypical depression. Antidepressants are widely considered to inhibit HPA activity, although inhibition is not unanimously reported in the literature. There is evidence, also uneven, that the mood stabilizers lithium and carbamazepine have the potential to augment HPA measures, while benzodiazepines, atypical antipsychotics, and to some extent, typical antipsychotics have the potential to inhibit HPA activity. Currently, the most reliable use of HPA measures in most disorders is to predict the likelihood of relapse, although changes in HPA activity have also been proposed to play a role in the clinical benefits of psychiatric treatments. Greater attention to patient heterogeneity and more consistent approaches to assessing treatment effects on HPA function may solidify the value of HPA measures in predicting treatment response or developing novel strategies to manage psychiatric disease.

Proinflammatory milieu in combat-related PTSD is independent of depression and early life stress

BACKGROUND

Chronic inflammation may be involved in combat-related post-traumatic stress disorder (PTSD) and may help explain comorbid physical diseases. However, the extent to which combat exposure per se, depression, or early life trauma, all of which are associated with combat PTSD, may confound the relationship between PTSD and inflammation is unclear.

METHODS

We quantified interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and C-reactive protein (CRP) in 51 combat-exposed males with PTSD and 51 combat-exposed males without PTSD, and assessed PTSD and depression severity as well as history of early life trauma. To decrease the possibility of Type I errors, we summed standardized scores of IL-1β, IL-6, TNFα, IFNγ and CRP into a total "pro-inflammatory score". PTSD symptom severity was assessed with the Clinician Administered PTSD Scale (CAPS) rating scale.

RESULTS

Subjects with PTSD had significantly higher pro-inflammatory scores compared to combat-exposed subjects without PTSD (p=0.006), and even after controlling for early life trauma, depression diagnosis and severity, body mass index, ethnicity, education, asthma/allergies, time since combat and the use of possibly confounding medications (p=0.002). Within the PTSD group, the pro-inflammatory score was not significantly correlated with depressive symptom severity, CAPS total score, or with the number of early life traumas.

CONCLUSIONS

Combat-related PTSD in males is associated with higher levels of pro-inflammatory cytokines, even after accounting for depression and early life trauma. These results, from one of the largest studies of inflammatory cytokines in PTSD to date, suggest that immune activation may be a core element of PTSD pathophysiology more so than a signature of combat exposure alone.

A phase-specific neuroimmune model of clinical depression

Immune dysfunction and pro-inflammatory states in particular have been implicated in the aetiology and pathogenesis of depression. Whilst the onset of an episode and certain symptoms of depression appear well explained by this inflammatory model, the underpinnings of the episodic and progressive nature, as well as relapse and remission status in depression require attention. In this review it is suggested that additional immune factors beyond pro- and anti-inflammatory cytokines may effectively contribute to the understanding of the neurobiology of clinical depression. Considering neurobiological effects of immunomodulatory factors such as T cells, macrophages, microglia and astrocytes relevant to depression, we suggest a neuroimmune model of depression underpinned by dynamic immunomodulatory processes. This perspective paper then outlines a neuroimmune model of clinical phases of depression in an attempt to more adequately explain depression-like behaviours in pre-clinical models and the dynamic nature of depression in clinical populations. Finally, the implications for immunomodulatory treatments of depression are considered.

Posttraumatic stress disorder post Iraq and Afghanistan: prevalence among military subgroups

A large body of research has been produced in recent years investigating posttraumatic stress disorder (PTSD) among military personnel following deployment to Iraq and Afghanistan, resulting in apparent differences in PTSD prevalence. We compare prevalence estimates for current PTSD between military subgroups, providing insight into how groups may be differentially affected by deployment. Systematic literature searches using the terms PTSD, stress disorder, and acute stress, combined with terms relating to military personnel, identified 49 relevant papers. Studies with a sample size of less than 100 and studies based on data for treatment seeking or injured populations were excluded. Studies were categorized according to theatre of deployment (Iraq or Afghanistan), combat and noncombat deployed samples, sex, enlistment type (regular or reserve and [or] National Guard), and service branch (for example, army, navy, and air force). Meta-analysis was used to assess PTSD prevalence across subgroups. There was large variability in PTSD prevalence between studies, but, regardless of heterogeneity, prevalence rates of PTSD were higher among studies of Iraq-deployed personnel (12.9%; 95% CI 11.3% to 14.4%), compared with personnel deployed to Afghanistan (7.1%; 95% CI 4.6% to 9.6%), combat deployed personnel, and personnel serving in the Canadian, US, or UK army or the navy or marines (12.4%; 95% CI 10.9% to 13.4%), compared with the other services (4.9%; 95% CI 1.4% to 8.4%). Contrary to findings from within-study comparisons, we did not find a difference in PTSD prevalence for regular active-duty and reserve or National Guard personnel. Categorizing studies according to deployment location and branch of service identified differences among subgroups that provide further support for factors underlying the development of PTSD.

Cancer-related fatigue--mechanisms, risk factors, and treatments

Fatigue is one of the most common adverse effects of cancer that might persist for years after treatment completion in otherwise healthy survivors. Cancer-related fatigue causes disruption in all aspects of quality of life and might be a risk factor of reduced survival. The prevalence and course of fatigue in patients with cancer have been well characterized and there is growing understanding of the underlying biological mechanisms. Inflammation seems to have a key role in fatigue before, during, and after cancer-treatment. However, there is a considerable variability in the presentation of cancer-related fatigue, much of which is not explained by disease-related or treatment-related characteristics, suggesting that host factors might be important in the development and persistence of this symptom. Indeed, longitudinal studies have identified genetic, biological, psychosocial, and behavioural risk factors associated with cancer-related fatigue. Although no current gold-standard treatment for fatigue is available, a variety of intervention approaches have shown beneficial effects in randomized controlled trials, including physical activity, psychosocial, mind-body, and pharmacological treatments. This Review describes the mechanisms, risk factors, and possible interventions for cancer-related fatigue, focusing on recent longitudinal studies and randomized trials that have targeted fatigued patients.

Dexamethasone stimulated gene expression in peripheral blood indicates glucocorticoid-receptor hypersensitivity in job-related exhaustion

Work-related stress can lead to various health problems ranging from job-related exhaustion to psychiatric and somatic diseases. Biomarkers of job-related exhaustion could help to improve our understanding of the biological mechanisms and might be useful to guide prevention and treatment strategies. The present study included 12 male cases suffering from job-related exhaustion and 12 matched healthy controls. Severity of exhaustion was assessed with the Maslach Burnout Inventory (MBI) and the Shirom-Melamed Burnout Measure (SMBM). Whole genome expression profiles derived from whole blood cells (baseline and following glucocorticoid-receptor (GR) stimulation with 1.5mg dexamethasone p.o.) and corresponding plasma cortisol levels were analyzed. All cases participated in regular aerobic exercise for 12 consecutive weeks and were then re-assessed at follow-up for exhaustion symptoms as well as for cortisol levels and gene expression profiles. At baseline, we found increased basal cortisol levels and an enhanced suppression of plasma cortisol concentrations following dexamethasone in cases suffering from job-related exhaustion. Gene expression analysis revealed that 1.6-fold more transcripts were significantly regulated by dexamethasone in cases as compared to controls. At follow-up after 12 weeks of regular exercise training which was accompanied by significantly improved exhaustion severity scores, cortisol levels and gene expression profiles of cases normalized to the levels observed in controls. In conclusion, we detected GR-induced neuroendocrine and gene expression changes in cases suffering from job-related exhaustion which are in line with an increased sensitivity of GR function. This GR dysregulation normalized with symptom recovery.

Lower health related quality of life in U.S. military personnel is associated with service-related disorders and inflammation

Military personnel who have combat exposures are at increased risk for the service-related disorders of post-traumatic stress disorder (PTSD), depression, sleep disturbances and decreased health related quality of life (HRQOL). Those with a traumatic brain injury (TBI) are at even greater risk. Inflammation is associated with these disorders and may underlie the risk for health declines. We evaluated 110 recently deployed, military personnel presenting with sleep disturbances for service-related disorders (TBI, PTSD, and depression) as well as HRQOL. ANOVA models were used to examine differences among military personnel with two or more service-related disorders (high comorbid group), or one or no disorders (low comorbid group). Logistic regression models were used to determine associations among interleukin-6 (IL-6) to HRQOL and service-related disorders. Approximately one-third of the sample had two or more service-related disorders. HRQOL was lower and IL-6 concentrations were higher in military personnel with PTSD or depression, with the most profound differences in those with more service-related disorders, regardless of sleep disorder. Having symptoms of depression and PTSD resulted in a 3.5-fold risk to be in the lower quartile of HRQOL and the highest quartile of IL-6. In a linear regression model, 41% of the relationship between HRQOL and IL-6 concentrations was mediated by PTSD and depression. Military personnel with PTSD and depression are at high risk for lower HRQOL, and higher IL-6 concentrations. Comprehensive treatment is required to address co-occurring service-related disorders in military personnel to promote health and well-being.

Efficacy of oxytocin administration early after psychotrauma in preventing the development of PTSD: study protocol of a randomized controlled trial

BACKGROUND

Currently few evidence based interventions are available for the prevention of PTSD within the first weeks after trauma. Increased risk for PTSD development is associated with dysregulated fear and stress responses prior to and shortly after trauma, as well as with a lack of perceived social support early after trauma. Oxytocin is a potent regulator of these processes. Therefore, we propose that oxytocin may be important in reducing adverse consequences of trauma. The 'BONDS' study is conducted in order to assess the efficacy of an early intervention with intranasal oxytocin for the prevention of PTSD.

METHODS/DESIGN

In this multicenter double-blind randomized placebo-controlled trial we will recruit 220 Emergency Department patients at increased risk of PTSD. Trauma-exposed patients are screened for increased PTSD risk with questionnaires assessing peri-traumatic distress and acute PTSD symptoms within 7 days after trauma. Baseline PTSD symptom severity scores and neuroendocrine and psychophysiological measures will be collected within 10 days after trauma. Participants will be randomized to 7.5 days of intranasal oxytocin (40 IU) or placebo twice a day. Follow-up measurements at 1.5, 3 and 6 months post-trauma are collected to assess PTSD symptom severity (the primary outcome measure). Other measures of symptoms of psychopathology, and neuroendocrine and psychophysiological disorders are secondary outcome measures.

DISCUSSION

We hypothesize that intranasal oxytocin administered early after trauma is an effective pharmacological strategy to prevent PTSD in individuals at increased risk, which is both safe and easily applicable. Interindividual and contextual factors that may influence the effects of oxytocin treatment will be considered in the analysis of the results.

TRIAL REGISTRATION

Netherlands Trial Registry: NTR3190.

Etiology of depression comorbidity in combat-related PTSD: a review of the literature

Posttraumatic stress disorder is often diagnosed with other mental health problems, particularly depression. Although PTSD comorbidity has been associated with more severe and chronic symptomology, relationships among commonly co-occurring disorders are not well understood. The purpose of this study was to review the literature regarding the development of depression comorbid with combat-related PTSD among military personnel. We summarize results of commonly tested hypotheses about the etiology of PTSD and depression comorbidity, including (1) causal hypotheses, (2) common factor hypotheses, and (3) potential confounds. Evidence suggests that PTSD may be a causal risk factor for subsequent depression; however, associations are likely complex, involving bidirectional causality, common risk factors, and common vulnerabilities. The unique nature of PTSD-depression comorbidity in the context of military deployment and combat exposure is emphasized. Implications of our results for clinical practice and future research are discussed.

Biomarkers in posttraumatic stress disorder: overview and implications for future research

PTSD can develop in the aftermath of traumatic incidents like combat, sexual abuse, or life threatening accidents. Unfortunately, there are still no biomarkers for this debilitating anxiety disorder in clinical use. Anyhow, there are numerous studies describing potential PTSD biomarkers, some of which might progress to the point of practical use in the future. Here, we outline and comment on some of the most prominent findings on potential imaging, psychological, endocrine, and molecular PTSD biomarkers and classify them into risk, disease, and therapy markers. Since for most of these potential PTSD markers a causal role in PTSD has been demonstrated or at least postulated, this review also gives an overview on the current state of research on PTSD pathobiology.

Pretrauma risk factors for posttraumatic stress disorder: a systematic review of the literature

As it has become clear that most individuals exposed to trauma do not develop PTSD, it has become increasingly important to examine pretrauma risk factors. However, PTSD research has overwhelmingly relied on retrospective accounts of trauma, which is beleaguered by problems of recall bias. To further our understanding of PTSD's etiology, a systematic review of 54 prospective, longitudinal studies of PTSD published between 1991 and 2013 were examined. Inclusion criteria required that all individuals were assessed both before and after an index trauma. Results revealed six categories of pretrauma predictor variables: 1) cognitive abilities; 2) coping and response styles; 3) personality factors; 4) psychopathology; 5) psychophysiological factors; and 6) social ecological factors. The results indicated that many variables, previously considered outcomes of trauma, are pretrauma risk factors. The review considered these findings in the context of the extant retrospective PTSD literature in order to identify points of overlap and discrepancy. Pretrauma predictor categories were also used to conceptualize variable risk for PTSD. Limitations and directions for future research are discussed.

Predicting PTSD: pre-existing vulnerabilities in glucocorticoid-signaling and implications for preventive interventions

Posttraumatic stress disorder (PTSD) is an anxiety disorder that may develop in response to a traumatic event. Approximately 10% of trauma-exposed individuals subsequently develop PTSD. It is hypothesized that the development of PTSD is associated with biological vulnerability factors, which are already present prior to the onset of symptoms. In this review we present an overview of currently identified vulnerability factors in the glucocorticoid (GC) signaling pathway for the development of PTSD. In addition, the implications of the identified vulnerability factors for potential preventive intervention strategies, including glucocorticoid receptor (GR) agonists and oxytocin, are discussed. Summarized, the findings of these studies indicate that individuals vulnerable for development of PTSD have dysregulations on various levels of the GC-signaling cascade: i.e. low levels of circulating levels of cortisol shortly after trauma, high GR number in peripheral blood mononuclear cells (PBMCs), high GILZ mRNA expression and low FKBP5 expression in PBMCs prior to trauma, and high sensitivity of T-cells for regulation by GCs prior to trauma. Furthermore, single nucleotide polymorphisms in the GR and FKBP5 genes have been found to be associated with increased risk for PTSD. Collectively, the identified vulnerability factors tentatively suggest that the development of PTSD may be preceded by a high sensitivity of various cells for regulation by GCs. The identification of these vulnerability factors may ultimately aid selective targeting of preventive interventions towards individuals at risk for PTSD. In addition, the identification of these vulnerability factors may eventually result in new preventive pharmacological strategies for PTSD.

Epigenetic Mechanisms Shape the Biological Response to Trauma and Risk for PTSD: A Critical Review

Posttraumatic stress disorder (PTSD) develops in approximately one-quarter of trauma-exposed individuals, leading us and others to question the mechanisms underlying this heterogeneous response to trauma. We suggest that the reasons for the heterogeneity relate to a complex interaction between genes and the environment, shaping each individual's recovery trajectory based on both historical and trauma-specific variables. Epigenetic modifications provide a unique opportunity to elucidate how preexisting risk factors may contribute to PTSD risk through changes in the methylation of DNA. Preexisting risks for PTSD, including depression, stress, and trauma, result in differential DNA methylation of endocrine genes, which may then result in a different biological responses to trauma and subsequently a greater risk for PTSD onset. Although these relationships are complex and currently inadequately described, we provide a critical review of recent studies to examine how differences in genetic and proteomic biomarkers shape an individual's vulnerability to PTSD development, thereby contributing to a heterogeneous response to trauma.

IL-1β reactivity and the development of severe fatigue after military deployment: a longitudinal study

Background

It has been suggested that pro-inflammatory cytokine signaling to the brain may contribute to severe fatigue. We propose that not only the level of circulating cytokines, but also increased reactivity of target cells to cytokines contributes to the effect of cytokines on behavior. Based on this concept, we assessed the reactivity of peripheral blood cells to IL-1β in vitro as a novel approach to investigate whether severe fatigue is associated with increased pro-inflammatory signaling.

Methods

We included 504 soldiers before deployment to a combat-zone. We examined fatigue severity and the response to in vitro stimulation with IL-1β prior to deployment (T0), and 1 (T1) and 6 months (T2) after deployment. IL-8 production was used as read-out. As a control we determined LPS-induced IL-8 production. The presence of severe fatigue was assessed with the Checklist Individual Strength (CIS-20R). Differences in dose–response and the longitudinal course of IL-1β and LPS-induced IL-8 production and fatigue severity were investigated using repeated measures ANOVA.

Results

At T2, the group who had developed severe fatigue (n = 65) had significantly higher IL-1β-induced IL-8 production than the non-fatigued group (n = 439). This group difference was not present at T0, but developed over time. Longitudinal analysis revealed that in the non-fatigued group, IL-1β-induced IL-8 production decreased over time, while IL-1β-induced IL-8 production in the fatigued group had not decreased. To determine whether the observed group difference was specific for IL-1β reactivity, we also analyzed longitudinal LPS-induced IL-8 production. We did not observe a group difference in LPS-induced IL-8 production.

Conclusions

Collectively, our findings indicate that severe fatigue is associated with a higher reactivity to IL-1β. We propose that assessment of the reactivity of the immune system to IL-1β may represent a promising novel method to investigate the association between behavioral abnormalities and pro-inflammatory cytokine signaling.