Effects of dehydroepiandrosterone supplementation during stressful military training: a randomized, controlled, double-blind field study

Intensive, Real-Time Data Collection of Psychological and Physiological Stress During a 96-Hour Field Training Exercise at a Senior Military College: Feasibility and Acceptability Cohort Study

BACKGROUND

Poor physical fitness, stress, and fatigue are factors impacting military readiness, national security, and economic burden for the United States Department of Defense. Improved accuracy of wearable biosensors and remote field biologic sample collection strategies could make critical contributions to understanding how physical readiness and occupational stressors result in on-the-job and environment-related injury, sleep impairments, diagnosis of mental health disorders, and reductions in performance in war-fighters.

OBJECTIVE

This study aimed to evaluate the feasibility and acceptability of intensive biomarker and biometric data collection to understand physiological and psychological stress in Army Reserved Officer Training Corps cadets before, during, and after a 96-hour field training exercise (FTX).

METHODS

A prospective pilot study evaluated the feasibility and acceptability of multimodal field data collection using passive drool saliva sampling, sweat sensors, accelerometry, actigraphy, and photoplethysmography. In addition, physical fitness (Army Combat Fitness Test), self-reported injury, and psychological resilience (Brief Resilience Scale) were measured.

RESULTS

A total of 22 cadets were included. Two were lost to follow-up due to injury during FTX, for a retention rate of 91%. Assessments of performance and psychological resilience were completed for all remaining participants, resulting in 100% testing adherence. All participants provided saliva samples before the FTX, with 98% adherence at the second time point and 91% at the third. For sweat, data collection was not possible. Average daily wear time for photoplethysmography devices was good to excellent, meeting a 70% threshold with data collected for ≥80% of person-days at all time points. Of the participants who completed the FTX and 12 completed a post-FTX acceptability survey for a response rate of 60%. Overall, participant acceptance was high (≥80%) for all metrics and devices.

CONCLUSIONS

This study demonstrates that wearable biosensors and remote field biologic sample collection strategies during a military FTX have the potential to be used in higher stakes tactical environments in the future for some, but not all, of the strategies. Overall, real-time biometric and biomarker sampling is feasible and acceptable during field-based training and provides insights and strategies for future interventions on military cadet and active-duty readiness, environmental stress, and recovery.

Acute Fatigue Responses to Occupational Training in Military Personnel: A Systematic Review and Meta-Analysis

INTRODUCTION

Military personnel are required to undertake rigorous physical training to meet the unique demands of combat, often leading to high levels of physiological stress. Inappropriate recovery periods with these high levels of physical stress may result in sub-optimal training and increased risk of injury in military personnel. However, no reviews have attempted to examine the magnitude of training-induced stress following military training activities. The aim of this systematic review was to assess the magnitude of physiological stress (physical, hormonal, and immunological) following task-specific training activities in military personnel.

METHODS

An extensive literature search was conducted within CINAHL, PubMed, Scopus, SportDiscus, and Web of Science databases with 7,220 records extracted and a total of 14 studies eligible for inclusion and evaluation. Study appraisal was conducted using the Kmet scale. Meta-analysis was conducted via forest plots, with standard mean difference (SMD, effect size) and inter-trial heterogeneity (I2) calculated between before (preactivity) and after (12-96 hours postactivity) military-specific activities for biomarkers of physiological stress (muscle damage, inflammation, and hormonal) and physical performance (muscular strength and power).

RESULTS

Military training activities resulted in significant levels of muscle damage (SMD = -1.28; P = .003) and significant impairments in strength and power (SMD = 0.91; P = .008) and testosterone levels (SMD = 1.48; P = .05) up to 96 hours postactivity. There were no significant differences in inflammation (SMD = -0.70; P = .11), cortisol (SMD = -0.18; P = .81), or insulin-like growth factor 1 (SMD = 0.65; P = .07) when compared to preactivity measures.

CONCLUSIONS

These findings indicate that assessments of muscle damage, anabolic hormones like testosterone, strength, and power are effective for determining the level of acute stress following military-specific activities. With regular monitoring of these measures, appropriate recovery periods may be implemented to optimize training adaptations and occupational performance, with minimal adverse training responses in military personnel.

Circulating biomarkers associated with performance and resilience during military operational stress

Adaptation to military operational stress is a complex physiological response that calls upon the sympathetic nervous system (SNS), hypothalamic pituitary adrenal (HPA) axis and immune system, to create a delicate balance between anabolism and catabolism and meet the demands of an ever-changing environment. As such, resilience, the ability to withstand and overcome the negative impact of stress on military performance, is likely grounded in an appropriate biological adaptation to encountered stressors. Neuroendocrine [i.e. cortisol, epinephrine (EPI), norepinephrine (NE), neuropeptide-Y (NPY), and brain derived neurotropic factor (BDNF)], inflammatory [i.e. interleukin 6 (IL-6), IL-1β, IL-4, IL-10 and tumour necrosis factor (TNF)-α], as well as growth and anabolic [i.e. insulin-like growth factor-I (IGF-I), testosterone, and dehydroepiandrosterone (DHEA)] biomarkers independently and interactively function in stress adaptations that are associated with a soldier's physical and psychological performance. In this narrative review, we detail biomarkers across neuroendocrine, inflammatory, and growth stimulating domains to better elucidate the biological basis of a resilient soldier. The findings from the reviewed studies indicate that military readiness and resiliency may be enhanced through better homeostatic control, better regulated inflammatory responses, and balanced anabolic/catabolic processes. It is unlikely that one class of biomarkers is better for assessing physiological resilience. Therefore, a biomarker panel that can account for appropriate balance across these domains may be superior in developing monitoring frameworks. Real-time physiological monitoring to assess biomarkers associated with resilience will be possible pending more sophisticated technologies and provide a field-expedient application for early identification and intervention of at-risk soldiers to improve military resiliency.

Blood and affective markers of stress in Elite Airmen during a preparatory training course: A pilot study

In highly stressful environments, individuals with diverging stress-reactivity can perform differently. Identification of blood markers of stress-reactivity is of major significance to help human performance during stress. Candidate transcripts were identified between stressed and non-stressed strains of rats’ blood and brain, and overlapping significant differentially expressed genes were selected. Serum levels of human orthologues of these proteins, in lieu of blood RNA, in addition to classic stress and general clinical markers, were measured in 33 Battlefield Airmen undergoing a 52 day long preparatory training course before their course of initial entry (COIE). Blood samples and factors of affective state, negative valence “Threat” and positive valence “Challenge”, were obtained five times across different days of training which included either routine physical exercise or prolonged and intense physical and mental training. During training, levels of chloride (Cl), dehydroepiandrosterone-sulfate (DHEA-S), creatinine kinase (CK), and total carbon dioxide (TCO2) differed between airmen who subsequently graduated from their COIE and those who did not. Time dependent changes of serum TCO2 and neuropeptide Y (NPY), as well as the affective factor Challenge differed by future graduation status throughout the training. Serum levels of parvin beta (PARVB) correlated with the affective factor Threat, while those of NPY, testosterone, coactosin like F-actin binding protein 1 (COTL1) and C-reactive protein (CRP) correlated with factor Challenge during the extended, intensive periods of training, consistently. These pilot data suggest that the identified panel of blood markers can measure stress responsiveness, which has the potential to advance individualized stress-management strategies.

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Levels of novel and classical serum markers signal stress severity in men.

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Biomarker levels reflect stress reactivity of Battlefield Airmen in training.

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Affective measures correlate with serum biomarkers after extended stress.

Dehydroepiandrosterone Supplementation May Benefit Women with Asthma Who Have Low Androgen Levels: A Pilot Study

Introduction

Among individuals with severe asthma, FEV₁ is low in individuals with low dehydroepiandrosterone (DHEA) sulfate (DHEAS) levels. In the Severe Asthma Research Program (SARP), no women with DHEAS > 200 μg/dL had an FEV₁ < 60% predicted. DHEA has benefited patients with COPD and pulmonary hypertension in small trials. Therefore, we hypothesized that DHEA supplementation may improve FEV₁ in asthmatic women with low DHEAS.

Methods

Premenopausal, nonsmoking, otherwise healthy women, 18-50 years old, with mild or moderate asthma and baseline FEV₁ > 60% predicted received 100 mg DHEA orally every 12 h for 2 weeks. Spirometry and DHEAS were measured at the initial visit and 2 weeks later, after completion of DHEA treatment. Based on our previous work, the primary outcome variable for this pilot study was post-albuterol spirometry in the low-DHEAS group. Subjects also continued their other routine asthma management.

Results

Serum DHEAS increased with DHEA treatment in women with starting DHEAS < 200 µg/dL: this increase was from 71 ± 23 to 725 ± 295 µg/dL (n = 10; p = 0.0001). The increase in the high-DHEAS group was smaller. Post-albuterol FEV₁ increased by 51 mL, from 3.026 ± 0.5 to 3.077 ± 0.49 L (n = 10; p = 0.034 by paired t test, significant after Bonferroni), in women with low DHEAS. In the high-DHEAS group (baseline DHEAS ≥ 200 µg/dl), post-albuterol FEV₁ did not change significantly (n = 3, p = NS). Three subjects were excluded: one had comorbid COPD, one could not perform spirometry, and one did not take the DHEA. There were no adverse effects of DHEA treatment in this trial.

Conclusions

Endocrine treatments (corticosteroids) are a mainstay of anti-inflammatory management for moderate and severe asthma. Their use has improved asthma outcomes. Androgens also reduce airway inflammation and promote airway smooth muscle relaxation, but are rarely used clinically for asthma treatment. Our results suggest that the over-the-counter steroid DHEA may improve lung function in asthma outcomes among women with DHEAS < 200 ug/dL.

The role of dehydroepiandrosterone on functional innate immune responses to acute stress

The androgen dehydroepiandrosterone (DHEA) responds to stress activation, exhibits anti-glucocorticoid properties, and modulates immunity in diverse ways, yet little is known of its role in acute stress responses. In this study, the effects of DHEA and its sulfate ester DHEA-S on human male immune function during exposure to an acute stressor is explored. Variation in DHEA, DHEA-S, testosterone, and cortisol, along with bacterial killing assays, was measured in response to a modified Trier Social Stress test in 27 young adult males. Cortisol was positively related to salivary innate immunity but only for participants who also exhibited high DHEA responses. Additionally, DHEA positively and DHEA-S negatively predicted salivary immunity, but the opposite was observed for serum-based innate immunity. The DHEA response to acute stress appears to be an important factor in stress-mediated immunological responses, with differential effects on immunity dependent upon the presence of other hormones, primarily cortisol and DHEA-S. These results suggest that DHEA plays an important role, alongside other hormones, in modulating immunological shifts during acute stress.

Adapting to Stress: Understanding the Neurobiology of Resilience

There is significant variation in the way individuals react and respond to extreme stress and adversity. While some individuals develop psychiatric conditions such as posttraumatic stress disorder or major depressive disorder, others recover from stressful experiences without displaying significant symptoms of psychological ill-health, demonstrating stress-resilience. To understand why some individuals exhibit characteristics of a resilient profile, the interplay between neurochemical, genetic, and epigenetic processes over time needs to be explained. In this review, we examine the hormones, neuropeptides, neurotransmitters, and neural circuits associated with resilience and vulnerability to stress-related disorders. We debate how this increasing body of knowledge could also be useful in the creation of a stress-resilient profile. Additionally, identification of the underlying neurobiological components related to resilience may offer a contribution to improved approaches toward the prevention and treatment of stress-related disorders.

Perceived Discrimination, Racial Identity, and Multisystem Stress Response to Social Evaluative Threat Among African American Men and Women

OBJECTIVE

Understanding individual differences in the psychobiology of the stress response is critical to grasping how psychosocial factors contribute to racial and ethnic health disparities. However, the ways in which environmentally sensitive biological systems coordinate in response to acute stress is not well understood. We used a social-evaluative stress task to investigate coordination among the autonomic nervous system, hypothalamic-pituitary-adrenal axis, and immune/inflammatory system in a community sample of 85 healthy African American men and women.

METHODS

Six saliva samples, 2 at each of baseline, event, and recovery phases of the stressor task, were assayed for cortisol, dehydroepiandrosterone-sulfate, salivary alpha-amylase, and salivary C-reactive protein. Individual differences in perceived discrimination and racial identity were also measured.

RESULTS

Factor analysis demonstrated that stress systems were largely dissociated before stressor exposure but became aligned during event and recovery phases into functional biological stress responses (factor loadings ≥ .58). Coordinated responses were related to interactions of perceived discrimination and racial identity: when racial identity was strong, highly perceived discrimination was associated with low hypothalamic-pituitary-adrenal axis activity at baseline (B's = .68-.72, p < .001), low stress mobilization during the task (B's = .46-.62, p < .049), and a robust inflammatory response (salivary C-reactive protein) during recovery (B's = .72-.94, p < .002).

CONCLUSION

Culturally relevant social perceptions may be linked to a specific pattern of changing alignment in biological components of the stress response. Better understanding these links may significantly advance understanding of stress-related illnesses and disparities.

Immune and Neuroendocrine Mechanisms of Stress Vulnerability and Resilience

Diagnostic criteria for mood disorders including major depressive disorder (MDD) largely ignore biological factors in favor of behavioral symptoms. Compounding this paucity of psychiatric biomarkers is a need for therapeutics to adequately treat the 30-50% of MDD patients who are unresponsive to traditional antidepressant medications. Interestingly, MDD is highly prevalent in patients suffering from chronic inflammatory conditions, and MDD patients exhibit higher levels of circulating pro-inflammatory cytokines. Together, these clinical findings suggest a role for the immune system in vulnerability to stress-related psychiatric illness. A growing body of literature also implicates the immune system in stress resilience and coping. In this review, we discuss the mechanisms by which peripheral and central immune cells act on the brain to affect stress-related neurobiological and neuroendocrine responses. We specifically focus on the roles of pro-inflammatory cytokine signaling, peripheral monocyte infiltration, microglial activation, and hypothalamic-pituitary-adrenal axis hyperactivity in stress vulnerability. We also highlight recent evidence suggesting that adaptive immune responses and treatment with immune modulators (exogenous glucocorticoids, humanized antibodies against cytokines) may decrease depressive symptoms and thus represent an attractive alternative to the current antidepressant treatments.

Anabolic hormone profiles in elite military men

We recently characterized the awakening responses and daily profiles of the catabolic stress hormone cortisol in elite military men. Anabolic hormones follow a similar daily pattern and may counteract the catabolic effects of cortisol. This companion report is the first to characterize daily profiles of anabolic hormones dehydroepiandrosterone (DHEA) and testosterone in this population. Overall, the men in this study displayed anabolic hormone profiles comparable to that of healthy, athletic populations. Consistent with the cortisol findings in our prior report, summary parameters of magnitude (hormone output) within the first hour after awakening displayed superior stability versus summary parameters of pattern for both DHEA (r range: 0.77-0.82) and testosterone (r range: 0.62-0.69). Summary parameters of evening function were stable for the two hormones (both p<0.001), while the absolute decrease in testosterone across the day was a stable proxy of diurnal function (p<0.001). Removal of noncompliant subjects did not appreciably affect concentration estimates for either hormone at any time point, nor did it alter the repeatability of any summary parameter. The first of its kind, this report enables accurate estimations of anabolic balance and resultant effects upon health and human performance in this highly resilient yet chronically stressed population.

Aggravation of Helicobacter pylori stomach infections in stressed military recruits

Objective

To investigate the effect of military stress on immune response and Helicobacter pylori stomach infections.

Methods

In this prospective, observational study, the Symptom Checklist-90 questionnaire was completed by military recruits before and following a 3-month basic training programme. H. pylori immunoglobulin (Ig)G levels, C¹⁴-urea breath-test values and levels of cortisol, catecholamine, and certain humoral and cellular immune responses were measured before and after the basic training.

Results

For 60 military recruits, somatization, depression and paranoid ideation scores were significantly increased after, compared with before, basic training. Post-training H. pylori IgG detection revealed three additional cases of H. pylori infection. Post-training C¹⁴-urea breath-test values were significantly higher compared with before training – thus suggesting higher levels of H. pylori colonization in the stomach. Post-training cortisol and catecholamine levels were increased, while serum IgG levels were decreased; complement component (C)3 and C4 levels remained unchanged. Post-training CD4⁺ and CD8⁺ T-cell percentages and the CD4⁺/CD8⁺ ratio were significantly reduced compared with before training. Serum interleukin (IL)-2 levels were lower and IL-10 levels were higher following training and there was a significant decrease in the IL-2/IL-10 ratio.

Conclusion

Military stress may reduce humoral and cellular immune responses and may aggravate the severity of H. pylori infection.

Genetic and environmental modulation of neurotrophic and anabolic stress response: Counterbalancing forces

The serotonin transporter genetic variant 5HTTLPR influences activation and feedback control of the hypothalamic-pituitary-adrenal axis, and has been shown to influence the effect of stressful life events on behavioral health. We recently reported that 5HTTLPR modulates cortisol response in healthy military men exposed to intense stress. Less is known of its combined effects with environmental factors in this context, or of its effect on neuroprotective stress responses. In this follow-up study, we examined the unique and combined effects of 5HTTLPR and prior trauma exposure on neuroprotective (salivary nerve growth factor [sNGF]), anabolic (dehydroepiandrosterone sulfate [DHEAS] and testosterone), and catabolic (cortisol) stress responses. Ninety-three healthy, active-duty military men were studied before, during, and 24h after a stressful 12-day survival course. Distinct and interactive effects of 5HTTLPR long allele carriage [L] versus homozygous short allele carriage [SS]) and prior trauma exposure (low versus high) were evaluated, after which a priori group comparisons were performed between hypothesized high resilience (L/low) and low resilience (SS/high) groups. For sNGF, L/low produced the greatest sNGF throughout stress exposure while SS/high demonstrated the smallest; L/high and SS/low bisected these two extremes and were nearly identical to each other (i.e., SS/high < SS/low = L/high < L/low). Thus, 5HTTLPR and prior trauma exposure demonstrated counterbalancing (additive) forces. Similar patterns were found for DHEAS. To our knowledge, this study is the first to report counterbalancing genetic and environmental effects on novel biomarkers related to resilience in humans exposed to real-world stress. These findings have profound implications for health, performance and training in high-stress occupational settings.

Sex differences in coping strategies in military survival school

A wealth of research has examined psychological responses to trauma among male military service members, but few studies have examined sex differences in response to trauma, such as coping strategies. This study assessed coping strategies used by male and female U.S. service members completing an intensely stressful mock-captivity exercise, compared strategies by sex, and assessed the relationship between coping and posttraumatic stress symptoms (PTSS). Two hundred service members (78% male) completed self-report surveys before and after mock captivity. Surveys assessed demographics, service characteristics, PTSS, and coping strategies used during mock captivity. Participants used seven coping strategies: denial, self-blame, religion, self-distraction, behavioral disengagement, positive reframing, and planning. Women used denial (p≤.05), self-blame (p≤.05), and positive reinterpretation (p≤.05) strategies more frequently than men, and they had higher PTSS levels following the exercise. Structural equation modeling showed that the relationship between sex and PTSS was fully mediated by coping strategies. The results of this study suggest that reducing the use of maladaptive coping strategies may mitigate PTSS among females. Future efforts should target improving coping during highly stressful and traumatic experiences.

Glucocorticoid-related predictors and correlates of post-traumatic stress disorder treatment response in combat veterans

The identification of biomarkers for post-traumatic stress disorder (PTSD) and resilience/recovery is critical for advancing knowledge about pathophysiology and treatment in trauma-exposed persons. This study examined a series of glucocorticoid-related biomarkers prior to and in response to psychotherapy. Fifty-two male and female veterans with PTSD were randomized 2 : 1 to receive either prolonged exposure (PE) therapy or a weekly minimal attention (MA) intervention for 12 consecutive weeks. Psychological and biological assessments were obtained prior to and following treatment and after a 12-week naturalistic follow-up. Response was defined dichotomously as no longer meeting criteria for PTSD at post-treatment based on the Clinician Administered PTSD Scale for DSM-IV (CAPS). Clinical improvement on the CAPS was apparent for both PE and MA, with no significant difference according to treatment condition. Biomarkers predictive of treatment gains included the BCLI polymorphism of the glucocorticoid receptor gene. Additional predictors of treatment response were higher bedtime salivary cortisol and 24 h urinary cortisol excretion. Pre-treatment plasma dehydroepiandrosterone/cortisol ratio and neuropetide Y (NPY) levels were predictors of reductions in PTSD symptoms, and, for NPY only, of other secondary outcomes as well, including anxiety and depression ratings. Glucocorticoid sensitivity changed in association with symptom change, reflecting clinical state. It is possible to distinguish prognostic and state biomarkers of PTSD using a longitudinal approach in the context of treatment. Identified markers may also be relevant to understanding mechanisms of action of symptom reduction.

Salivary nerve growth factor response to intense stress: effect of sex and body mass index

Ample evidence links stress to psychiatric and neurological disease. Although many studies examine stress hormone secretion and receptor activity, exciting new developments signify a shift in focus to neuromodulatory systems influencing neuronal development, survival, and neuroplasticity. The purpose of this study was to characterize salivary nerve growth factor (sNGF) responses to intense stress exposure in healthy military members undergoing survival training. A second purpose was to explore effects of age, sex, education, and body mass index (BMI). One hundred sixteen military members (80% male) were studied before, during, and 24 h after a stressful mock-captivity exercise. sNGF was measured at all three time points. Reactivity, recovery, and residual elevation of sNGF were computed. General linear modeling with repeated measures evaluated effect of stress exposure, as well as the roles of age, sex, education, and BMI. sNGF increased 137% from baseline to intense stress. During recovery, sNGF remained elevated an average of 67% above baseline (i.e., residual elevation). Men showed greater sNGF reactivity than women quantified by larger absolute T1-T2Δ (+148.1 pg/mL vs. +64.9 pg/mL, p<0.017). A noteworthy trend of higher sNGF concentrations in low BMI participants was observed (p=0.058). No effects of age or education were shown. This study shows substantial reactivity and residual elevation of sNGF in response to intense stress exposure in healthy humans. Further research is needed to refine the sNGF assay, fully characterize the sNGF stress response, delineate correlates and mechanisms, and validate therapeutic applications.

Revisão sistemática dos aspectos psicossociais, neurobiológicos, preditores e promotores de resiliência em militares

Objetivo: Conduzir uma revisão sistemática sobre resiliência psicológica e/ou hardiness em militares, explorando seus aspectos psicossociais, neurobiológicos, preditores e promotores. Métodos: Utilizaram-se as bases de dados PubMed/MedLine, ISI/Web of Science e PsycINFO, incluindo artigos empíricos publicados nas línguas inglesa, portuguesa e espanhola até maio de 2012. Os seguintes termos foram utilizados: “militar*”, “Army”, “war”, “veteran*”, “resilien*” e “hardiness”. Resultados: Foram incluídos 32 estudos selecionados a partir de 1.205 artigos. O foco da maioria das pesquisas recai sobre a correlação resiliência/hardiness e aspectos psicossociais. Confirmou-se o papel protetivo da resiliência/hardiness quanto ao transtorno de estresse pós-traumático (TEPT), assim como a associação direta entre resiliência e saúde. Neuropeptídeo Y (NPY) e deidroepiandrosterona (DHEA) foram os biomarcadores mais estudados. Os níveis de NPY no plasma podem representar um correlato biológico de resiliência ou recuperação dos efeitos adversos do estresse. Somente dois estudos abordaram fatores preditores de resiliência em amostras militares, sugerindo ser a exposição a situações adversas, o apoio social e o gênero fatores considerados preditores desse construto. Apenas um estudo avaliou a eficiência de intervenção para fortalecer a resiliência. Conclusão: Apesar da crucial relevância da resiliência, há poucos estudos em amostras militares. Estudos neurobiológicos como os do NPY são promissores. A ausência de ensaio randomizado controlado avaliando eficácia de intervenções promotoras da resiliência demonstra como esse construto vem sendo negligenciado nessa profissão de risco, constituindo área prioritária para foco de estudos futuros.

Sex differences in cardiovascular and subjective stress reactions: prospective evidence in a realistic military setting

Evidence points to heightened physiological arousal in response to acute stress exposure as both a prospective indicator and a core characteristic of posttraumatic stress disorder (PTSD). Because females may be at higher risk for PTSD development, it is important to evaluate sex differences in acute stress reactions. This study characterized sex differences in cardiovascular and subjective stress reactions among military survival trainees. One hundred and eighty-five military members (78% males) were studied before, during, and 24 h after stressful mock captivity. Cardiovascular (heart rate [HR], systolic blood pressure [SBP], diastolic blood pressure [DBP]) and dissociative states were measured at all three time points. Psychological impact of mock captivity was assessed during recovery. General linear modeling with repeated measures evaluated sex differences for each cardiovascular endpoint, and causal steps modeling was used to explore interrelationships among sex, cardiovascular reactions and psychological impact of mock captivity. Although females had lower SBP than males at all three time points, the difference was most pronounced at baseline and during stress. Accordingly, females showed greater residual elevation in SBP during recovery. Females had lower DBP at all three time points. In addition, females reported greater psychological impact of mock captivity than males. Exploratory causal steps modeling suggested that stress-induced HR may partially mediate the effect of sex on psychological impact of mock captivity. In conclusion, this study demonstrated sex-specific cardiovascular stress reactions in military personnel, along with greater psychological impact of stress exposure in females. This research may elucidate sex differences in PTSD development.

Psychometric and neurobiological assessment of resilience in a non-clinical sample of adults

BACKGROUND

Resilient individuals are capable of adjusting and coping successfully in the face of adversity. Efforts to assess resilience and its biomarkers have focused on individuals with a history of trauma and related disorders.

OBJECTIVE

To psychologically assess resilience in a non-clinical community population through questionnaires, and analyse the associations between the psychological parameters and salivary cortisol and dehydroepiandrosterone sulphate (DHEA-S) as putative biomarkers of resilience.

METHOD

An opportunistic sample (n=196) completed a cross-sectional survey assessing resilience, self-reported depressive symptoms and anxiety, and possible correlates. A sub-sample (n=32) selected in order to maximise variation of mental health, provided saliva samples for enzyme-linked immunoassay (ELISA) detection of cortisol and DHEA-S.

RESULTS

Resilience correlated negatively with depressive symptoms, trait anxiety and early life stress, and positively with self-efficacy, optimism, social support and wellbeing (all r>0.40; all p-values ≤0.001 except for early life stress: r=-0.20; p≤0.05). Resilience and DHEA-S concentrations correlated significantly (r=0.35; p≤0.05); this relationship remained stable after adjustment for demographics. Gender differences were observed for DHEA-S and cortisol (p≤0.05).

CONCLUSION

Resilience is associated with positive aspects of psychological health and salivary DHEA-S, suggesting the latter can be treated as a biomarker of resilience in a non-clinical sample of adults.

Spontaneous and deliberate dissociative states in military personnel: are such states helpful?

This study explored distinctions between spontaneous and deliberate dissociative states in 335 military personnel exposed to stressful survival training. Participants completed the Clinician-Administered Dissociative States Scale (CADSS) after a stressful mock-captivity event. They were also asked to indicate whether the dissociative experiences just happened (i.e., spontaneous), or whether they chose to have them happen (i.e., deliberate); and whether they appraised the dissociative experience as helpful (i.e., facilitative) or hurtful (i.e., debilitative) to their ability to cope with the stressful event. A majority (95.4%) endorsed dissociative states during stress. More than half (57.4%) described dissociative experiences as spontaneous, 13.0% as deliberate, and 29.5% endorsed neither. In Special Forces soldiers only, those who endorsed facilitative dissociation exhibited higher total CADSS scores than those who endorsed debilitative dissociation. Seventy-three percent of spontaneous dissociators described the experience as debilitative to coping with stress; conversely, 76% of deliberate dissociators said these experiences facilitated coping with stress. Individuals with prior trauma exposure tended to appraise dissociative states as more debilitative to coping. This research may enhance the fidelity of studies of dissociation constructs and may offer pivot points for prevention and treatment of stress-related disorders.

Neurobiology of resilience

Humans exhibit a remarkable degree of resilience in the face of extreme stress, with most resisting the development of neuropsychiatric disorders. Over the past 5 years, there has been increasing interest in the active, adaptive coping mechanisms of resilience; however, in humans, most published work focuses on correlative neuroendocrine markers that are associated with a resilient phenotype. In this review, we highlight a growing literature in rodents that is starting to complement the human work by identifying the active behavioral, neural, molecular and hormonal basis of resilience. The therapeutic implications of these findings are important and can pave the way for an innovative approach to drug development for a range of stress-related syndromes.