Neuroendocrine and immune responses to a cognitive stress challenge in veterans with and without PTSD

Proton Magnetic Resonance Spectroscopy in Post-Traumatic Stress Disorder-Updated Systematic Review and Meta-Analysis

A stressor-related disorder wherein traumatic experience precipitates protracted disruptions to mood and cognition, post-traumatic stress disorder (PTSD) is associated with wide-ranging abnormalities across the body. While various methods have investigated these deviations, only proton magnetic resonance spectroscopy (¹H MRS) enables noninvasive measurement of small-molecule metabolites in the living human. ¹H MRS has correspondingly been employed to test hypotheses about the composition and function of multiple brain regions putatively involved in PTSD. Here we systematically review methodological considerations and reported findings, both positive and negative, of the current ¹H-MRS literature in PTSD (N = 32 studies) to communicate the brain regional metabolite alterations heretofore observed, providing random-effects model meta-analyses for those most extensively studied. Our review suggests significant PTSD-associated decreases in N-acetyl aspartate in bilateral hippocampus and anterior cingulate cortex with less evident effect in other metabolites and regions. Model heterogeneities diverged widely by analysis (I² < 0.01% to 90.1%) and suggested regional dependence on quantification reference (creatine or otherwise). While observed variabilities in methods and reported findings suggest that ¹H-MRS explorations of PTSD could benefit from methodological standardization, informing this standardization by quantitative assessment of the existing literature is currently hampered by its small size and limited scope.

Mechanisms of Shared Vulnerability to Post-traumatic Stress Disorder and Substance Use Disorders

Psychoactive substance use is a nearly universal human behavior, but a significant minority of people who use addictive substances will go on to develop an addictive disorder. Similarly, though ~90% of people experience traumatic events in their lifetime, only ~10% ever develop post-traumatic stress disorder (PTSD). Substance use disorders (SUD) and PTSD are highly comorbid, occurring in the same individual far more often than would be predicted by chance given the respective prevalence of each disorder. Some possible reasons that have been proposed for the relationship between PTSD and SUD are self-medication of anxiety with drugs or alcohol, increased exposure to traumatic events due to activities involved in acquiring illegal substances, or addictive substances altering the brain's stress response systems to make users more vulnerable to PTSD. Yet another possibility is that some people have an intrinsic vulnerability that predisposes them to both PTSD and SUD. In this review, we integrate clinical and animal data to explore these possible etiological links between SUD and PTSD, with an emphasis on interactions between dopaminergic, adrenocorticotropic, GABAergic, and glutamatergic neurobehavioral mechanisms that underlie different emotional learning styles.

A decennial review of psychotraumatology: what did we learn and where are we going?

On 6 December 2019 we start the 10th year of the European Journal of Psychotraumatogy (EJPT), a full Open Access journal on psychotrauma. This editorial is part of a special issue/collection celebrating the 10 years anniversary of the journal where we will acknowledge some of our most impactful articles of the past decade (also discussed below and marked with * in the reference list). In this editorial the editors present a decennial review of the field addressing a range of topics that are core to both the journal and to psychotraumatology as a discipline. These include neurobiological developments (genomics, neuroimaging and neuroendocrine research), forms of trauma exposure and impact across the lifespan, mass trauma and early interventions, work-related trauma, trauma in refugee populations, and the potential consequences of trauma such as PTSD or Complex PTSD, but also resilience. We address innovations in psychological, medication (enhanced) and technology-assisted treatments, mediators and moderators like social support and finally how new research methods help us to gain insights in symptom structures or to better predict symptom development or treatment success. We aimed to answer three questions 1. Where did we stand in 2010? 2. What did we learn in the past 10 years? 3. What are our knowledge gaps? We conclude with a number of recommendations concerning top priorities for the future direction of the field of psychotraumatology and correspondingly the journal.

The hypothalamic-pituitary-adrenal axis in PTSD: Pathophysiology and treatment interventions

Questions of how altered functioning of the hypothalamic pituitary adrenal (HPA) axis contribute to the development and maintenance of posttraumatic stress disorder (PTSD) have been the focus of extensive animal and human research. As a rule, results have been inconsistent across studies, likely due to a variety of confounding variables that have received inadequate attention. Important confounding factors include the effects of early life stress, biological sex, and the glucocorticoid used for interventions. In this manuscript we review: 1) the literature on identified abnormalities of HPA axis function in PTSD, both in terms of basal functioning and as part of challenge paradigms; 2) the role of HPA axis function pre- and immediately post-trauma as a risk factor for PTSD development; 3) the impact of HPA axis genes' allelic variants and epigenetic modifications on PTSD risk; 4) the contributions of HPA axis components to fear learning and extinction; and 5) therapeutic manipulations of the HPA axis to both prevent and treat PTSD, including the role of glucocorticoids as part of medication enhanced psychotherapy.

Recent advances in the neurobiology of posttraumatic stress disorder: A review of possible mechanisms underlying an effective pharmacotherapy

Recent progress in the field of neurobiology supported by clinical evidence gradually reveals the mystery of human brain functioning. So far, many psychiatric disorders have been described in great detail, although there are still plenty of cases that are misunderstood. These include posttraumatic stress disorder (PTSD), which is a unique disease that combines a wide range of neurobiological changes, which involve disturbances of the hypothalamic-pituitary-adrenal gland axis, hyperactivation of the amygdala complex, and attenuation of some hippocampal and cortical functions. Such multiplicity results in differential symptomatology, including elevated anxiety, nightmares, fear retrieval episodes that may trigger delusions and hallucinations, sleep disturbances, and many others that strongly interfere with the quality of the patient's life. Because of widespread neurological changes and the disease manifestation, the pharmacotherapy of PTSD remains unclear and requires a multidimensional approach and involvement of polypharmacotherapy. Hopefully, more and more neuroscientists and clinicians will study PTSD, which will provide us with new information that would possibly accelerate establishment of well-tolerated and effective pharmacotherapy. In this review, we have focused on neurobiological changes regarding PTSD, addressing the most disturbed brain structures and neurotransmissions, as well as discussing in detail the recently taken and novel therapeutic paths.

Anxiolytic-like effects of paeoniflorin in an animal model of post traumatic stress disorder

Post-traumatic stress disorder (PTSD) is the serious psychiatric disorder. Paeoniflorin (PF) produces the antidepressant-like properties. However, few studies are concerned about its anti-PTSD-like effects and mechanisms. To investigate these, the single prolonged stress (SPS) model was utilized. PTSD-like behavioral deficits in rats after exposure to SPS were improved by PF (10 and 20 mg/kg, i.p.), evidenced by blocking increased freezing time in contextual fear paradigm (CFP) and increased time and entries in open arms in elevated plus maze (EPM) test without affecting the locomotor activity in open field (OF) test. We also found that increased levels of corticosterone (Cort), corticotropin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) after exposure to SPS were reversed by PF (10 and 20 mg/kg, i.p.) in serum, respectively. Moreover, the decreased levels of serotonin (5-HT) and 5-Hydroxyindoleacetic acid (5-HIAA) in prefrontal cortex and hippocampus were reversed by PF (10 and 20 mg/kg, i.p.), respectively. In summary, the anti-PTSD-like activities of PF were associated with the modulation of HPA axis and 5-HT system activation.

Neurotransmitter, Peptide, and Steroid Hormone Abnormalities in PTSD: Biological Endophenotypes Relevant to Treatment

PURPOSE OF REVIEW

This review summarizes neurotransmitter, peptide, and other neurohormone abnormalities associated with posttraumatic stress disorder (PTSD) and relevant to development of precision medicine therapeutics for PTSD.

RECENT FINDINGS

As the number of molecular abnormalities associated with PTSD across a variety of subpopulations continues to grow, it becomes clear that no single abnormality characterizes all individuals with PTSD. Instead, individually variable points of molecular dysfunction occur within several different stress-responsive systems that interact to produce the clinical PTSD phenotype. Future work should focus on critical interactions among the systems that influence PTSD risk, severity, chronicity, comorbidity, and response to treatment. Effort also should be directed toward development of clinical procedures by which points of molecular dysfunction within these systems can be identified in individual patients. Some molecular abnormalities are more common than others and may serve as subpopulation biological endophenotypes for targeting of currently available and novel treatments.

Growth hormone deficiency after mild combat-related traumatic brain injury

OBJECTIVE

Traumatic brain injury (TBI) has been recognized as a cause of growth hormone deficiency (GHD) in civilians. However, comparable data are sparse in veterans who incurred TBI during combat. Our objective was to determine the prevalence of GHD in veterans with a history of combat-related TBI, and its association with cognitive and psychosocial dysfunction.

DESIGN

Single center prospective study.

PATIENTS

Twenty male veterans with mild TBI incurred during combat 8-72 months prior to enrollment.

MEASUREMENTS

GHD was defined by a GH peak <3 μg/L during glucagon stimulation test. Differences in neuropsychological, emotional, and quality of life of the GHD Veterans were described using Cohen's d. Large effect sizes were considered meaningful.

RESULTS

Mean age was 33.7 years (SD 7.8) and all subjects had normal thyroid hormone and cortisol levels. Five (25%) exhibited a subnormal response to glucagon. Sixteen participants (80%) provided sufficient effort for valid neuropsychological assessment (12 GH-sufficient, 4 GHD). There were large effect size differences in self-monitoring during memory testing (d = 1.46) and inhibitory control (d = 0.92), with worse performances in the GHD group. While fatigue and post-traumatic stress disorder were comparable, the GHD group reported more depression (d = 0.80) and lower quality of life (d = 0.64).

CONCLUSIONS

Our study found a 25% prevalence of GHD in veterans with mild TBI as shown by glucagon stimulation. The neuropsychological findings raise the possibility that GHD has adverse effects on executive abilities and mood. Further studies are needed to determine whether GH replacement is an effective treatment in these patients.

Workplace injury data reported by occupational physicians and general practitioners

BACKGROUND

Accurate workplace injury data are useful in the prioritization of prevention strategies. In the UK, physicians report workplace ill-health data within The Health and Occupation Research (THOR) network, including injury case reports.

AIMS

To compare workplace injury data reported by occupational physicians (OPs) and general practitioners (GPs) to THOR.

METHODS

Injury cases reported by OPs and GPs, reported to THOR between 2006 and 2012 were analysed. Demographics, industrial groups, nature of injury, kind of accident and site of injury were compared. Data on sickness absence for workplace injuries reported by GPs were investigated.

RESULTS

In total, 2017 workplace injury cases were reported by OPs and GPs. Males were more likely to sustain a workplace accident than females. Sprains and strains were reported most often, with the upper limbs being affected most frequently. Slips, trips and falls were identified as important causal factors by both OPs and GPs. Psychological injuries also featured in THOR reporting, with a higher proportion reported by OPs (21%) than by GPs (3%). The proportion of people classified as 'unfit' by GPs reduced following the introduction of the 'fit' note.

CONCLUSIONS

THOR reports returned by OPs and GPs provide a valuable source of information of workplace injury data, and complement other sources of information, such as the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations and the Labour Force Survey.

Stress-related factors in the emergence of transient global amnesia with hippocampal lesions

The transient global amnesia (TGA) is a rare amnesic syndrome that is characterized by an acute onset episode of an anterograde and retrograde amnesia. Its origin is still debated, but there is evidence for psychological factors involved in TGA. In neuroimaging, selective lesions in the CA1 field of the hippocampus can be detected, a region that is particularly involved in the processing of memory, stress and emotion. The aim of this study was to assess the role of psychological stress in TGA by studying the prevalence of stress related precipitating events and individual stress-related personality profiles as well as coping strategies in patients. The hypothesis of a functional differentiation of the hippocampus in mnemonic and stress-related compartments was also evaluated. From all 113 patients, 18% (n = 24) patients experienced emotional and psychological stress episodes directly before the TGA. In a cohort of 21 acute patients, TGA patients tend to cope with stress less efficiently and less constructively than controls. Patients who experienced a stress related precipitant event exhibited a higher level of anxiety in comparison to non-stress patients and controls. However, there was no difference between the general experience of stress and the number of stress inducing life events. The majority of patients (73%) did show typical magnetic resonance imaging (MRI) lesions in the CA1 region of the hippocampal cornu ammonis. There was no clear association between stressful events, distribution of hippocampal CA1 lesions and behavioral patterns during the TGA. Disadvantageous coping strategies and an elevated anxiety level may increase the susceptibility to psychological stress which may facilitate the pathophysiological cascade in TGA. The findings suggest a role of emotional stress factors in the manifestation of TGA in a subgroup of patients. Stress may be one trigger involved in the emergence of transient lesions in the hippocampal CA1 region, which are thought to be the structural and functional correlate of TGA.

The Interface of Stress and the HPA Axis in Behavioural Phenotypes of Mental Illness

Abnormalities of hypothalamic-pituitary-adrenal (HPA) axis function are one of the most consistent biological findings across several mental disorders, but many of the mechanisms underlying this abnormality as well as the potential contribution to behavioural phenotypes remain only partially understood. Interestingly, evidence suggests a U-curve, with dysregulation of the HPA axis towards both hyper- or hypoactivity manifesting as a risk to mental wellbeing. This review will elaborate on both the clinical and molecular role of the neuroendocrine stress system in depressive, psychotic and post-traumatic stress disorders and present some of the most recent findings that have shed light on the complex interface between environmental stressors, molecular mechanisms and clinical presentation. Crucially, plasticity of the HPA axis confers both vulnerability to adverse events, particularly so in early developmental stages, as well as hope for the treatment of mental disorder, as evidenced by changes in HPA functioning associated with remission of symptoms.

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.

Neuroendocrine and immune responses to a cognitive stress challenge in veterans with and without PTSD

BACKGROUND

PTSD has been associated with altered hypothalamus-pituitary-adrenal-axis (HPA-axis), immune and sympathetic nervous system (SNS) regulation. The purpose of this study was to evaluate the effect of cognitive stress on these systems in PTSD patients and controls.

METHODS

The subjective units of distress score (SUDS), NK-cell response, plasma levels of noradrenalin and ACTH in response to cognitive stress were assessed in male veterans with PTSD (n=15) and age, region and year of deployment matched veterans without psychopathology (n=15).

RESULTS

The challenge induced an increase in SUDS, noradrenalin, ACTH and NK-cell response in both groups. Baseline levels of ACTH were lower in PTSD patients. The test was experienced as more stressful by PTSD patients and resulted in an augmented ACTH response in patients. The noradrenalin and NK-cell responses showed no group differences. The ACTH response correlated with the severity of symptoms in patients, and the noradrenalin response correlated with the ACTH and NK-cell response in controls, but not in patients.

DISCUSSION

PTSD patients experience more distress and present with an exaggerated pituitary response to this stressor. In addition, our results suggest an altered interaction between the HPA-axis, SNS and immune system in PTSD.