Indirect associations of combat exposure with post-deployment physical symptoms in U.S. soldiers: roles of post-traumatic stress disorder, depression and insomnia

The ambivalence about accepting the prevalence somatic symptoms in PTSD: Is PTSD a somatic disorder?

This study examined the prevalence of somatic symptoms in post-traumatic stress disorder (PTSD) in a population-based military sample (N = 14,445). Descriptive statistics explored somatic symptom endorsement in the entire sample. A latent class analyses was conducted on participants with a posttraumatic stress checklist (PCL) score ≥29 (n = 2433), with class differentiated by somatic symptom endorsement.Multinomial logistic regression explored correlates of latent class. Somatic disorder was more prevalent in probable-PTSD (59.6%) and subsyndromal-PTSD (26.5%) than no-PTSD (5.0%) groups, supporting an intersection of pathophysiological processes between somatic and PTSD symptoms. A 3-class solution of Syndromal (26.7%),Psychological (17.7%), and Somatic (55.5%) classes provided the optimal representation of latent somatic symptom typologies in probable PTSD and subsyndromal PTSD. Differences between classes on key characteristics supported potentially meaningful class distinctions. Class was not predicted by number of deployments nor whether a member had ever deployed. However, class was predicted by life-time trauma, indicating that the PTSD somatic symptom relationship is not confined to combat related PTSD or the effect of toxic exposures on deployment, but that pre-existing pathophysiology related to life-time trauma may drive the relationship.The high degree of coincidence between PTSD and somatic symptoms and the high prevalence of somatic distress in the Syndromal and Somatic classes support somatic symptoms are a ubiquitous aspect of the clinical presentation and should be considered a central characteristic of PTSD and therefore included in the diagnostic criteria, as suggested by the original formulations of PTSD.

The Associations Between Physical and Psychological Symptoms and Traumatic Military Deployment Exposures

Current paradigms regarding the effects of traumatic exposures on military personnel do not consider physical symptoms unrelated to injury or illness as independent outcomes of trauma exposure, characteristically dealing with these symptoms as comorbidities of psychological disorders. Our objective was to ascertain the proportions of deployed military personnel who experienced predominantly physical symptoms, predominantly psychological symptoms, and comorbidity of the two and to examine the association between traumatic deployment exposures (TDEs) and these symptomatic profiles. Data were taken from a cross-sectional study of Australian Defence Force personnel who were deployed to the Middle East during 2001-2009 (N = 14,032). Four groups were created based on distributional splits of physical and psychological symptom scales: low-symptom, psychological, physical, and comorbid. Multinomial logistic regression models assessed the probability of symptom group membership, compared with low-symptom, as predicted by self-reported TDEs. Group proportions were: low-symptom, 78.3%; physical, 5.0%; psychological, 9.3%; and comorbid, 7.5%. TDEs were significant predictors of all symptom profiles. For subjective, objective, and human death and degradation exposures, respectively, the largest relative risk ratios (RRRs) were for the comorbid profile, RRRs = 1.47, 1.19, 1.48; followed by the physical profile, RRRs = 1.27, 1.15, 1.40; and the psychological profile, RRRs = 1.22, 1.07, 1.22. Almost half of participants with physical symptoms did not have comorbid psychological symptoms, suggesting that physical symptoms can occur as a discrete outcome trauma exposure. The similar dose-response association between TDEs and the physical and psychological profiles suggests trauma is similarly associated with both outcomes.

Posttraumatic Stress Disorder Severity and Insomnia-Related Sleep Disturbances: Longitudinal Associations in a Large, Gender-Balanced Cohort of Combat-Exposed Veterans

Few studies have investigated the range and severity of insomnia-related sleep complaints among veterans with posttraumatic stress disorder (PTSD), and the temporal association between insomnia and PTSD severity has yet to be examined. To examine these associations, a large, gender-balanced cohort of veterans (N = 1,649) of the Iraq and Afghanistan conflicts participated in longitudinal assessments of PTSD and insomnia-related symptoms over a period of 2.5 years following enrollment (range: 2-4 years). Data were obtained from multiple sources, including interviews, self-report assessments, and electronic medical record data. Three-fourths (74.0%) of veterans with PTSD diagnoses at Time 1 (T1) reported insomnia-related sleep difficulties on at least half the nights during the past 30 days, and one-third of participants had received a prescription for a sedative-hypnotic drug in the past year. Veterans without PTSD had fewer sleep problems overall, although the prevalence of sleep problems was high among all study participants. In longitudinal, cross-lagged panel models, the frequency of sleep problems at T1 independently predicted increases in PTSD severity at Time 2 (T2), B = 0.27, p < .001, after controlling for gender and relevant comorbidities. Conversely, T1 PTSD severity was associated with increasing sleep complaints at T2 but to a lesser degree, B = 0.04, p < .001. Moderately high rates of sedative-hypnotic use were seen in veterans with PTSD, with more frequent use in women compared to men (40.4% vs. 35.0%). Sleep complaints were highly prevalent overall and highlight the need for increased clinical focus on this area.

The Value of Physical Symptoms in Screening For Posttraumatic Stress Disorder in the Military

Physical symptoms are highly comorbid with posttraumatic stress disorder (PTSD). As PTSD is underdiagnosed, this study explored the value of self-reported physical symptoms in screening for 30-day PTSD in military personnel. Two physical symptom scales were constructed using items from a 67-item health symptom checklist, clinical interviews were used as the diagnostic reference standard, and diagnostic utility of physical symptoms was compared with the current gold standard screen, the PTSD checklist (PCL). Receiver operating characteristic analyses showed that both a 9-item and a 10-item physical symptom scale were of value in predicting PTSD (areas under the curve 0.81 and 0.85). Importantly, two thirds of PTSD positive personnel missed by the PCL were captured with physical symptoms scales, and when physical symptoms were added to the PCL, prediction was improved (areas under the curve 0.90 to 0.92). Our findings highlight the value of including assessing physical symptoms in PTSD screening.

Association Between Predeployment Optimism and Onset of Postdeployment Pain in US Army Soldiers

IMPORTANCE

Pain after deployment is a major health care concern. While risk factors have been previously studied, few studies have explored protective factors.

OBJECTIVE

To examine the prospective association between predeployment optimism and the onset of new pain after deployment in US Army soldiers.

DESIGN, SETTING, AND PARTICIPANTS

This prospective longitudinal cohort study examined US Army soldiers (active duty, Reserve, and National Guard) who deployed to Afghanistan or Iraq between February 12, 2010, and August 29, 2014, and completed the necessary psychological and health assessments before and after deployment. Analyses were performed in the Person-Event Data Environment between July 2016 and November 2018. This study relied exclusively on existing, secondary Army data. Of the 413 763 Army soldiers who met the specified deployment criteria, 385 925 soldiers were missing 1 or more of the required assessment forms. Of the remaining 27 838 soldiers who were examined for eligibility, 7104 soldiers were excluded because of preexisting back pain, joint pain, or frequent headaches. These exclusions resulted in a final analytic sample of 20 734 eligible soldiers.

MAIN OUTCOMES AND MEASURES

This study examined new reports of pain after deployment, including new back pain, joint pain, and frequent headaches.

RESULTS

Among 20 734 US Army soldiers (87.8% male; mean [SD] age, 29.06 [8.42] years), 37.3% reported pain in at least 1 new area of the body after deployment: 25.3% reported new back pain, 23.1% reported new joint pain, and 12.1% reported new frequent headaches. As a continuous measure, each 1-U increase in optimism was associated with 11% lower odds of reporting any new pain after deployment, even while adjusting for demographic, military, and combat factors (odds ratio, 0.89; 95% CI, 0.86-0.93). Tertile analyses revealed that compared with soldiers with high optimism (lowest odds of new pain) soldiers with low optimism had 35% greater odds of reporting new pain in any of the 3 sites evaluated (odds ratio, 1.35; 95% CI, 1.21-1.50). In addition, a larger increase in risk of new pain was observed when comparing the moderate-optimism and low-optimism groups rather than the high-optimism and moderate-optimism groups.

CONCLUSIONS AND RELEVANCE

Higher levels of optimism were associated with lower odds of reporting new pain after deployment, over and above other common determinants of pain, including demographic and military characteristics and combat experiences. Soldiers with low levels of optimism before deployment could benefit from programs geared toward enhancing optimism.

Deployment of personnel to military operations: impact on mental health and social functioning

This Campbell systematic review examines the effects of deployment on mental health. The review summarizes evidence from 185 studies. All studies used observational data to quantify the effect of deployment. This review includes studies that evaluate the effects of deployment on mental health. A total of 185 studies were identified. However, only 40 of these were assessed to be of sufficient methodological quality to be included in the final analysis. The studies spanned the period from 1993 to 2017 and were mostly carried out in the USA, UK and Australia. The studies all had some important methodological weaknesses. None of the included studies used experimental designs (random assignment). Deployment to military operations negatively affects the mental health functioning of deployed military personnel. For assessments taken more than 24 months since exposure, we consistently found adverse effects of deployment on all mental health domains (PTSD, depression, substance abuse/dependence, and common mental disorders), particularly on PTSD. For assessments taken less than 24 months (or a variable number of months since exposure) the evidence was less consistent and in many instances inconclusive.

Plain language summary

Deployment to military operations negatively affects the mental health functioning of deployed military personnel: While additional research is needed, the current evidence strongly supports the notion that deployment negatively affects mental health functioning of deployed military personnel.What is this review about?: When military personnel are deployed to military operations abroad they face an increased risk of physical harm, and an increased risk of adverse shocks to their mental health.The primary condition under consideration is deployment to an international military operation. Deployment to a military operation is not a uniform condition; rather, it covers a range of scenarios. Military deployment is defined as performing military service in an operation at a location outside the home country for a limited time period, pursuant to orders.The review included studies that reported outcomes for individuals who had been deployed. This review looked at the effect of deployment on mental health outcomes. The mental health outcomes are: post-traumatic stress disorder (PTSD), major depressive disorder (MDD), common mental disorders (depression, anxiety and somatisation disorders) and substance-related disorders.By identifying the major effects of deployment on mental health and quantifying these effects, the review can inform policy development on deployment and military activity as well as post-deployment support for veterans. In this way the review enables decision-makers to prioritise key areas.What are the main findings of this review?: What studies are included?: This review includes studies that evaluate the effects of deployment on mental health. A total of 185 studies were identified. However, only 40 of these were assessed to be of sufficient methodological quality to be included in the final analysis. The studies spanned the period from 1993 to 2017 and were mostly carried out in the USA, UK and Australia. The studies all had some important methodological weaknesses. None of the included studies used experimental designs (random assignment).Does deployment have an effect on mental health?: Deployment to military operations negatively affects the mental health functioning of deployed military personnel. For assessments taken more than 24 months since exposure, we consistently found adverse effects of deployment on all mental health domains (PTSD, depression, substance abuse/dependence, and common mental disorders), particularly on PTSD. For assessments taken less than 24 months (or a variable number of months since exposure) the evidence was less consistent and in many instances inconclusive.What do the findings of this review mean?: The odds of screening positive for PTSD and depression were consistently high in the longer term. This suggests that efforts should be increased to detect and treat mental disorders, as effects may be long-lasting.Overall the risk of bias in the majority of included studies was high. While it is difficult to imagine a randomised study design to understand how deployment affects mental health, other matters such as changes to personnel policy, or unanticipated shocks to the demand for military personnel, could potentially be a rich source of quasi-experimental variation.How up-to-date is this review?: The review authors searched for studies up to 2017. This Campbell systematic review was published in March 2018.

Executive summary

BACKGROUND: When military personnel are deployed to military operations abroad they face an increased risk of physical harm, and an increased risk of adverse shocks to their mental health. Research suggests that the increased risk to mental health is mainly due to the hazards of war, combat exposure: firing weapons, road side bombs, seeing fellow soldiers, friends, civilians, and enemies being injured, maimed or killed. These experiences may lead to severe mental stress. The adverse impact on mental health is the psychological cost of war, and it is of interest to policymakers to learn the magnitude of these effects. This review sets out to synthesise available evidence about the consequences of deployment for deployed military personnel in the mental health and social functioning domains.OBJECTIVES: The objective of this review isto synthesise the consequences of deployment to military operation on the mental health and social functioning of deployed military personnel.SEARCH METHODS: We searched electronic databases, grey literature, and references from primary studies and related reviews. No language or date restrictions were applied to the searches. We searched the following electronic databases: Academic Search Elite, Cochrane Library, EMBASE, ERIC, MEDLINE, PsycINFO, Science Citation Index, Social Science Citation Index, SocINDEX, as well as the Nordic platforms: bibliotek.dk, BIBSYS, and LIBRIS. The conclusions of this review are based on the most recent searches performed. The last search was performed in April 2017.SELECTION CRITERIA: Primary studies had to meet the following inclusion criteria: Participants: The participants should be military personnel.Intervention: The condition should be deployment to a military operation.Comparison: The relevant comparisons were either comparing a) deployed military personnel to non-deployed military personnel, b) deployed military personnel to military personnel deployed elsewhere, for example personnel deployed to non-combat operations, c) military personnel deployed to the same operation but stratified by combat exposure.Outcomes: The study should report on one or more mental health outcomes, and/or social functioning for the deployed participants. In particular studies should report on one or more of the following mental health outcomes: PTSD, major depression, substance abuse or dependence (including alcohol), and common mental disorders (depression and anxiety disorders). The following social functioning outcomes were relevant: employment, and homelessness.Study Designs: Both experimental and quasi-experimental designs with a comparison group were eligible for inclusion in the review. Studies were excluded if they: Reported on deployments taking place before 1989.Used a within group pre-post study design.Did not report on at least one of the mental health or social functioning outcomes. DATA COLLECTION AND ANALYSIS: The total number of potentially relevant studies constituted31,049records. A total of 185 studies met the inclusion criteria and were critically appraised by the review authors. The final selection of 185 studies was from 13 different countries.Forty eight of the 185 studies did not report effect estimates or provide data that would allow the calculation of an effect size and standard error. Fifty four studies were excluded because of overlapping samples. The majority of those studies were from USA but the main reason for not using studies from USA in the synthesis was lack of information to calculate an effect size. Nearly half the studies from the UK could not be used in the synthesis due to overlap of data samples. Forty three studies were judged to have a very high risk of bias (5 on the scale) and, in accordance with the protocol, we excluded these from the data synthesis on the basis that they would be more likely to mislead than inform., Thus a total of 40 studies, from five different countries, were included in the data synthesis.Random effects models were used to pool data across the studies. We used the odds ratio. Pooled estimates were weighted with inverse variance methods, and 95% confidence intervals were calculated. The meta-analyses were carried out by time since exposure (short, medium, long, and other time since exposure) and by type of comparison (deployed versus non-deployed, all deployed but stratified by either combat operations versus non-combat operations, or stratified by combat exposure). We performed single factor subgroup analysis. The assessment of any difference between subgroups was based on 95% confidence intervals. Funnel plots were used to assess the possibility of publication bias. Sensitivity analysis was used to evaluate whether the pooled effect sizes were robust across components of methodological quality.MAIN RESULTS: The findings were mixed, depending on the outcome, the time since exposure and the approach (deployed versus non-deployed termed absolute or stratified by extent of combat termed relative) used to investigate the effect. It was not possible to analyse the outcomes homelessness and employment. All studies that could be used in the data synthesis reported on the impact of deployment on mental health; PTSD, depression, substance use or common mental disorder.For assessments taken less than 24 months since exposure the evidence was inconclusive either because too few studies reported results in the short and medium term and/or the degree of heterogeneity between studies was large.For assessments taken at other time points (a variable number of months since exposure) the evidence was inconclusive for the relative comparisons due to either too few studies or a substantial degree of heterogeneity between studies. For the absolute comparison the analysis of common mental disorder was inconclusive, whereas the average effects of PTSD and depression were positive and statistically significant (PTSD odds ratio (OR) was 1.91 (95% confidence interval (CI): 1.28 to 2.85) and OR=1.98 (95% CI: 1.05 to 3.70) for depression). The analysis concerning substance use indicated that deployed participants did not have higher odds of screening positive for substance use compared to non-deployed participants (OR=1.15 (95% CI: 0.98 to 1.36)).For assessments taken more than 24 months post exposure, meta-analyses indicated that the odds of screening positive for PTSD, depression, substance use and common mental disorder were higher for participants in the deployed group compared to participants in the group that were not deployed (PTSD OR=3.31 (95% CI: 2.69 to 4.07), OR=2.19 (95% CI: 1.58 to 3.03) for depression, OR=1.27 (95% CI: 1.15 to 1.39) for substance use, and OR=1.64 (95% CI: 1.38 to 1.96) for common mental disorder). Likewise, participants reporting high combat exposure had higher odds of screening positive for PTSD and depression than participants reporting lower exposure for long term assessments (PTSD OR=3.05 (95% CI: 1.94 to 4.80) and OR=1.81 (95% CI: 1.28 to 2.56) for depression). The analyses of substance use and common mental disorder were inconclusive due to too few studies.On the basis of the prevalence of mental health problems in pre-deployed or non-deployed population based comparison sampleswe would therefore expect the long term prevalence of PTSD in post-deployed samples to be in the range 6.1 - 14.9%, the long term prevalence of depression to be in the range from 7.6% to 18%, the long term prevalence of substance use to be in the range from 2.4% to 17.5% and the prevalence of common mental disorder to be in the range from 10% to 23%.Sensitivity analyses resulted in no appreciable change in effect size, suggesting that the results are robust.It was only possible to assess the impact of two types of personnel characteristics (branch of service and duty/enlistment status) on the mental health outcomes. We found no evidence to suggest that the effect of deployment on any outcomes differ between these two types of personnel characteristics.AUTHORS' CONCLUSIONS: Deployment to military operations negatively affects the mental health functioning of deployed military personnel. We focused on the effect of deployment on PTSD (post-traumatic stress disorder), depression, substance abuse/dependence, and common mental disorders (depression and anxiety disorders). For assessments taken less than 24 months (or a variable number of months since exposure) the evidence was less consistent and in many instances inconclusive. For assessments taken more than 24 months since exposure, we consistently found adverse effects of deployment on all domains, particularly on PTSD. There is increased political awareness of the need to address post deployment mental health problems. The odds of screening positive for PTSD and depression were consistently high in the longer term. This suggests that efforts should be increased to detect and treat mental disorders, as effects may be long lasting. Mental illness is of particular concern in the military for operational reasons, but they may be hard to detect in the military setting because a military career is intimately linked with mental and physical strength.It was not possible to examine a number of factors which we had reason to expect would impact on the magnitude of the effect. This would have been particularly relevant from a policy perspective because these are direct parameters that one could use to optimally "organize" deployment in order to minimize impacts on mental health functioning.While additional research is needed, the current evidence strongly supports the notion that deployment negatively affects mental health functioning of deployed military personnel. The next step is to begin to examine preventive measures and policies for organizing deployment, in order to minimize the effects on mental health.

Behavioral and Health Outcomes Associated With Deployment and Nondeployment Acquisition of Traumatic Brain Injury in Iraq and Afghanistan Veterans

OBJECTIVE

To characterize behavioral and health outcomes in veterans with traumatic brain injury (TBI) acquired in nondeployment and deployment settings.

DESIGN

Cross-sectional assessment evaluating TBI acquired during and outside of deployment, mental and behavioral health symptoms, and diagnoses.

SETTING

Veterans Affairs Medical Centers.

PARTICIPANTS

Iraq and Afghanistan veterans who were deployed to a warzone (N=1399).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Comprehensive lifetime TBI interview, Structured Clinical Interview for DSM-IV Disorders, Combat Exposure Scale, and behavioral and health measures.

RESULTS

There was a main effect of deployment TBI on depressive symptoms, posttraumatic stress symptoms, poor sleep quality, substance use, and pain. Veterans with deployment TBI were also more likely to have a diagnosis of bipolar, major depressive, alcohol use, and posttraumatic stress disorders than those who did not have a deployment TBI.

CONCLUSIONS

TBIs acquired during deployment are associated with different behavioral and health outcomes than TBI acquired in nondeployment environments. The presence of TBI during deployment is associated with poorer behavioral outcomes, as well as a greater lifetime prevalence of behavioral and health problems in contrast to veterans without deployment TBI. These results indicate that problems may persist chronically after a deployment TBI and should be considered when providing care for veterans. Veterans with deployment TBI may require treatment alterations to improve engagement and outcomes.

Depression in Female Veterans Returning from Deployment: The Role of Social Factors

Objective

Women are serving in the armed forces and deployed to areas of conflict in increasing numbers. Problems such as depressive symptoms and risks related to combat exposure can have negative effects on adjustment following service; understanding the relationship between these problems may contribute to strategies providers can use to facilitate healthy adjustment after deployment. The purpose of this study is to examine social factors as they relate to mental health adjustment, namely depressive symptoms among female veterans who served in Iraq and Afghanistan as part of Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn (OND). We hypothesized that combat exposure would predict higher levels of depressive symptoms and that social support would moderate the relationship between combat exposure and depression.

Methods

In a cross-sectional design, 128 female Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn veterans completed an online survey about combat experience, social support, depression, demographic characteristics, and behavioral health symptom history. We conducted multiple regression analyses to examine linear and moderating relationships.

Results

There was no significant relationship between combat exposure and depression; social support did not significantly moderate the relationship between combat exposure and depression. However, higher levels of social support and financial comfort were significantly related to lower levels of depression.

Conclusion

This study highlights the role of social factors, specifically social support and perceived financial status, as potential barriers to healthy emotional readjustment following deployment. These findings suggest that it may be beneficial for mental health providers to screen female veterans and refer them to appropriate services to reduce financial stressors and strengthen their use of social support. More research should continue to examine more fully the impact of combat exposure on female service members' mental health and work to isolate the factors most strongly related to depression.

Combat exposure and pain in male and female Afghanistan and Iraq veterans: The role of mediators and moderators

Veterans experience physical health problems associated with disability and poor quality of life following combat exposure (CE). Understanding the CE-physical health relationship, specifically pain intensity and somatic pain, may inform etiological models and interventions. This study examined the CE-pain relationship, associated mediators, and gender as a moderator. 2381 veterans at the VA San Diego Healthcare System completed paper or electronic self-report measures of pain intensity and somatic pain. Analyses examined associations of pain with CE and posttraumatic stress disorder (PTSD), depression, and resilience as mediators of the CE-pain association. Moderated mediation models explored gender as a moderator of significant mediated pathways. Controlling for age, veterans with CE had significantly higher pain intensity and somatic pain, and PTSD and depression scores significantly mediated the CE-pain relationships. Gender significantly moderated the CE-pain intensity association through depression scores such that the indirect effect was stronger for female veterans relative to male veterans. CE is associated with pain intensity and somatic pain, with greater levels of PTSD and depression mediating the CE-pain link and gender moderating the depression mediated CE-pain association. Future studies should examine gender differences and mediators in the CE-pain relationships using longitudinal designs to inform etiological models and targeted pain interventions.

Epidemiology of Major Depressive Disorder Disability in the US Military: FY 2007-2012

This study assesses the incidence of major depressive disorder (MDD) disability discharge and retirement in the Army, Navy, Marine Corps and Air Force and describes MDD comorbidity. Service members with a disability discharge for either MDD (n = 2,882) or any nonpsychiatric disability (n = 56,145), between fiscal years 2007 and 2012, were included in the study population. Those with MDD disability at first evaluation but not at last evaluation were excluded. The incidence of MDD disability discharge increased significantly in the Army and Air Force between fiscal years 2007 and 2012. MDD disability retirement significantly increased in the Army, Navy, and Air Force. Females, and those who experienced at least one deployment, had higher incidence rates of MDD disability discharge. All services included spinal diseases and posttraumatic stress disorder in their top five comorbid categories. Given the association between trauma and MDD, further research into the role of both combat exposure and injury on MDD is merited.

The "yin and yang" of the adrenal and gonadal systems in elite military men

We recently established daily, free-living profiles of the adrenal hormone cortisol, the (primarily adrenal) anabolic precursor dehydroepiandrosterone (DHEA) and the (primarily gonadal) anabolic hormone testosterone in elite military men. A prevailing view is that adrenal and gonadal systems reciprocally modulate each other; however, recent paradigm shifts prompted the characterization of these systems as parallel, cooperative processes (i.e. the "positive coupling" hypothesis). In this study, we tested the positive coupling hypothesis in 57 elite military men by evaluating associations between adrenal and gonadal biomarkers across the day. Salivary DHEA was moderately and positively coupled with salivary cortisol, as was salivary testosterone. Anabolic processes (i.e. salivary DHEA and testosterone) were also positively and reliably coupled across the day. In multivariate models, salivary DHEA and cortisol combined to account for substantial variance in salivary testosterone concentrations across the day, but this was driven almost exclusively by DHEA. This may reflect choreographed adrenal release of DHEA with testicular and/or adrenal release of testosterone, systemic conversion of DHEA to testosterone, or both. DHEA and testosterone modestly and less robustly predicted cortisol concentrations; this was confined to the morning, and testosterone was the primary predictor. Altogether, top-down co-activation of adrenal and gonadal hormone secretion may complement bottom-up counter-regulatory functions to foster anabolic balance and neuronal survival; hence, the "yin and yang" of adrenal and gonadal systems. This may be an adaptive process that is amplified by stress, competition, and/or dominance hierarchy.

Sleep Disturbance in Posttraumatic Stress Disorder: Epiphenomenon or Causal Factor?

PURPOSE OF REVIEW

The goal of this review is to integrate recent findings on sleep disturbance and PTSD, examine sleep disturbance as a causal factor in the development of PTSD, and identify future directions for research, treatment, and prevention.

RECENT FINDINGS

Recent research highlights a relationship between both objective and subjective sleep disturbance and PTSD across diverse samples. Sleep disturbance also predicts PTSD over time. Finally, treatments targeting sleep disturbance lead to decreased PTSD symptoms, while standard PTSD treatments conclude with residual sleep disturbance. Sleep disturbance may be more than a mere epiphenomenon of PTSD. Future research examining the causal role of sleep disturbance in the development of PTSD, as well as the utility of targeting sleep disturbance in prevention and treatment, is necessary to fully understand the likely bidirectional relationship between sleep disturbance and PTSD.