Trends in mental health outcomes and combat exposure among US marines returning from Iraq, Afghanistan or other deployments, 2004-13.

BACKGROUND: As of 2015, more than 2.7 million US military Veterans have served in support of the Global War on Terror. The negative sequelae associated with deployment stressors and related traumas are well-documented. Although data on mental health issues are routinely collected from service members returning from deployment, these data have not been made publicly available, leaving researchers and clinicians to rely on convenience samples, outdated studies and small sample sizes. METHODS: Population-based data of US Marines returning from deployment between 2004 and 2013 were analyzed, using the Post-Deployment Health Assessment. RESULTS: Rates of Marines returning from Iraq who screened positive for depression ranged from 19.31 to 30.02%; suicidal ideation ranged from 0 to 1.44%. Marines screening positive for PTSD ranged from 3.00 to 12.41%; combat exposure ranged from 15.58 to 55.12%. Depression was indicated for between 12.54 and 30.04% of Marines returning from Afghanistan, while suicidal ideation ranged from 0 to 5.33%. PTSD percentages ranged from 6.64 to 18.18%; combat exposure ranged between 42.92 and 75%. CONCLUSION: Our results support the heterogeneity of experiences and mental health sequelae of service members returning from deployments. Outcomes for Afghanistan and Iraq Veterans fluctuate with changes in OPTEMPO across theaters over time.

Predictors of Posttraumatic Stress Disorder, Anxiety Disorders, Depressive Disorders, and Any Mental Health Condition Among U.S. Soldiers and Marines, 2001-2011.

Understanding mental health disorder diagnosis and treatment seeking among active-duty military personnel is a topic with both clinical and policy implications. It has been well documented in military populations that individual-level military experience, including deployment history and combat exposure, influences mental health outcomes, but the impact of unit-level factors is less well understood. In the current study, we used administrative longitudinal data to examine a comprehensive set of unit- and individual-level predictors of posttraumatic stress disorder (PTSD), non-PTSD anxiety disorders, depressive disorders, and overall mental health diagnoses among Army and Marines Corps personnel. Using Cox survival models for time-dependent variables, we analyzed time from military accession (between January 1, 2001 and December 31, 2011) until first mental health diagnosis for 773,359 soldiers and 332,093 Marines. Prior diagnosis of a substance abuse disorder during one's military career, hazard ratios (HRs) = 1.68-3.10, and cumulative time spent deployed, HRs = 1.11-2.04, were the most predictive risk factors for all outcomes. Male sex, HRs = 0.35-0.57, and officer rank, HRs = 0.13-0.23, were the most protective factors. Unit-level rate of high deployment stress was a small but significant predictor of all outcomes after controlling for individual-level deployment history and other predictors, HRs = 1.01-1.05. Findings suggest both unit- and individual-level risk and protective factors of mental health diagnoses associated with treatment seeking. Clinical, including mental health assessment and management, and policy implications related to the military environment and the individual as it relates to mental health disorders are discussed.

Graphic Novels: A New Stress Mitigation Tool for Military Training: Developing Content for Hard-to-Reach Audiences.

This article describes the development of two graphic novels as a new approach to mental health communication and coping strategies for the Navy and Marine Corps. The novels are intended to capture the attention of the younger target audience and provide vital teaching messages to better prepare personnel for deployment to combat zones. The novels were developed based on embedding the principles of combat and operational stress control (COSC) into realistic and relatable characters, stories, and images. Approaches used for development included (a) basing storylines on real-life service members and the situations they face in combat and their personal lives; (b) partnering with COSC experts to embed teaching points; (c) ensuring technical accuracy through research and target audience reviews of the storyboard and artwork; (d) developing characters that are representative of the target audience, with varied jobs, ages, backgrounds, and professional concerns; and (e) designing artwork in a manner sensitive to training objectives and the psychological effects on readers. Because technical accuracy, realism, and sensitivity were noted as essential components of an effective graphic novel tool, focus-group research and review of author drafts by the target audience and technical experts are strongly recommended.

Prevalence of perceived stress and mental health indicators among reserve-component and active-duty military personnel.

OBJECTIVES: We examined stress levels and other indicators of mental health in reservists and active-duty military personnel by deployment status. METHODS: We used data from the Department of Defense Health-Related Behaviors surveys, which collect comprehensive, population-based data for reserve and active-duty forces. Data were collected from 18 ,342 reservists and 16, 146 active-duty personnel. RESULTS: Overall, with adjustment for sociodemographic and service differences, reservists reported similar or less work and family stress, depression, and anxiety symptoms than did active-duty personnel. However, reservists who had been deployed reported higher rates of suicidal ideation and attempts than did active-duty personnel who had been deployed and higher rates of post-traumatic stress disorder symptomatology than did any active-duty personnel and reservists who had not been deployed. The highest rates of suicidal ideation and attempts were among reservists who had served in theaters other than Iraq and Afghanistan. CONCLUSIONS: Our results suggest that deployment has a greater impact on reservists than on active-duty members, thus highlighting the urgent need for services addressing reservists' unique postdeployment mental health issues. Also, deployment to any theater, not only Iraq or Afghanistan, represents unique threats to all service members' mental well-being.

Comparative analysis of mandated versus voluntary administrations of post-deployment health assessments among Marines.

Little empirical data exist regarding candidness of service members' responses on the mandated Post-Deployment Health Reassessment (PDHRA) administered 3 to 6 months postdeployment. This study reports on the agreement between responses from U.S. Marines on a subset of the military-administered mandatory PDHRA items and answers to the same subset of items embedded in confidential research surveys. Results show that personnel are clearly underreporting certain symptoms and conditions on the mandatory PDHRA. The most dramatic increases in reporting on the research study's PDHRA items, as indicated by the percentage ratio, were for self-harming ideation and concern about harming others, each of which has about 14 times the endorsement percentage on the survey as on the official PDHRA. Lack of agreement for some items may be the result of resolution or onset of more acute conditions, but disagreement on sensitive behavioral concerns suggests that mandated PDHRAs are not effective screens for those domains.

Postdeployment alcohol use, aggression, and post-traumatic stress disorder.

Current military personnel are at risk of developing serious mental health problems, including chronic stress disorders and substance use disorders, as a result of military deployment. The most frequently studied effect of combat exposure is post-traumatic stress disorder (PTSD). High-risk behaviors, including alcohol use and aggression, have been associated with PTSD, but the optimal cutoff score on the PTSD Checklist (PCL) for determining the risk for these behaviors has not been clearly delineated. Using postdeployment active duty (AD) and Reserve component military personnel, the relation between various cutoff scores on the PCL and engaging in high-risk behaviors was examined. AD personnel, for every outcome examined, showed significantly greater odds for each problem behavior when PCL scores were 30 or higher compared to those with PCL scores in the 17 to 29 range. A similar pattern was shown for Reserve component personnel with respect to several problem behaviors, although not for alcohol use behaviors. The differences in problem behaviors for these two populations may be an indication that deployment experiences and combat exposure affect them differently and suggest that despite lower critical PCL scores, AD personnel may be at higher risk for developing problems as a function of the deployment cycle.

Approaches to the primary prevention of posttraumatic stress disorder in the military: a review of the stress control literature.

Numerous studies are underway, using data collected from clinical studies and data collected from surveys of combat troops, to determine the most efficacious treatment options for those diagnosed with posttraumatic stress disorder (PTSD). In contrast, little is known about the effectiveness of predeployment training in preventing or mitigating the impact of combat-related stressors on the development of PTSD. We conducted a comprehensive review of literature pertaining to primary prevention efforts to stem the advent of PTSD and other combat and operational stress injuries in military populations using databases from the peer-reviewed literature as well as online searches and colleague referrals. Results show that, as with treatment for PTSD, the most promising preventive approaches appear to utilize exposure strategies, especially those in conjunction with education and stress reduction skills training.

Use of Mobile Technology Paired with Heart Rate Monitor to Remotely Quantify Behavioral Health Markers among Military Reservists and First Responders.

INTRODUCTION: Heart rate variability (HRV) is a biological marker that reflects an individual's autonomic nervous system regulation. Psychological resilience is an individual's ability to recover from an adverse event and return to physiological homeostasis and mental well-being, indicated by higher resting HRV. The Biofeedback Assisted Resilience Training (BART) study evaluates a resilience-building intervention, with or without HRV biofeedback. This article evaluates the feasibility of remote psychophysiological research by validating the HRV data collected. MATERIALS AND METHODS: The BART platform consists of a mobile health application (BART app) paired to a wearable heart rate monitor. The BART app is installed on the participant's personal phone/tablet to track and collect self-report psychological and physiological data. The platform collects raw heart rate data and processes HRV to server as online biofeedback. The raw data is processed offline to derive HRV for statistical analysis. The following HRV parameters are validated: inter-beat interval, respiratory sinus arrhythmia, low-frequency HRV, biofeedback HRV, and heart period. Bland-Altman and scatter plots are used to compare and contrast online and offline HRV measures. Repeated-measures ANOVA are used to compared means across tasks during the stress (rest, stress, and recovery) and training (rest and paced breathing) sessions in order to validate autonomic nervous system changes to physiological challenges. RESULTS: The analyses included 245 participants. Bland-Altman plots showed excellent agreement and minimal bias between online and offline unedited inter-beat interval data during the stress session. RMANOVA during the training session indicated a significant strong effect on biofeedback HRV, F(11,390) = 967.96, P < .01. During the stress session, RMANOVA showed significant strong effect on respiratory sinus arrhythmia and low-frequency HRV, and a significant but weak effect on heart period. CONCLUSIONS: The BART digital health platform supports remote behavioral and physiological data collection, intervention delivery, and online HRV biofeedback.

Measurement invariance of posttraumatic stress disorder symptoms among U.S. military personnel.

Studies have not examined the factor structure or measurement invariance of posttraumatic stress disorder (PTSD) symptomatology using population-based data. Confirmatory factor analysis of the PTSD Checklist-Civilian Version (PCL-C) was conducted in a representative sample of U.S. active duty military personnel (N = 15,593). Consistent with prior research, a 4-factor model consisting of reexperiencing, avoidance, emotional numbing, and arousal factors was superior to four alternative models. Measurement invariance was found for factor loadings, but not observed item intercepts when comparing personnel with and without a recent deployment (

Substance use and mental health trends among U.S. military active duty personnel: key findings from the 2008 DoD Health Behavior Survey.

OBJECTIVE: Examine substance use and mental health issues among U.S. military personnel. METHODS: Data were from the 2008 (and before) population-based Department of Defense Health Related Behavior Surveys. The sample size for the 2008 survey was 28,546 (70.6% response rate). RESULTS: Analyses examined substance use, stress, depression, post-traumatic stress disorder (PTSD), suicidal ideation and attempts, deployment, and job satisfaction. Trends show reductions in tobacco use and illicit drug use, but increases in prescription drug misuse, heavy alcohol use, stress, PTSD, and suicidal attempts. Deployment exacerbated some of these behavior changes. Despite the demanding lifestyle, job satisfaction was high. CONCLUSIONS: The military has shown progress in decreasing cigarette smoking and illicit drug use. Additional emphasis should be placed on understanding increases in prescription drug misuse, heavy alcohol use, PTSD, and suicide attempts, and on planning additional effective interventions and prevention programs. Challenges remain in understanding and addressing military mental health needs.

Mental health, stress, and resilience correlates of heart rate variability among military reservists, guardsmen, and first responders.

The use of heart rate variability (HRV) for monitoring stress has been growing in the behavioral health literature, especially in the areas of posttraumatic stress disorder, stress reactivity, and resilience. Few studies, however, have included general populations under workplace conditions. This study evaluates whether military and other first responders show lower HRV during stress than at baseline and greater post stress rebound, controlling for a myriad of potential confounders. A convenience sample of Reserves, National Guard, veteran, fire, and police personnel provided HRV and self-reported questionnaire responses before, during, and after a cognitive-stressor task with a smart phone application. Timing of HRV application; mental and physical health scores; coping and posttraumatic growth indicators, including being open to new possibilities; and emotional support were predictors of trajectories of the HRV response to stress. Findings from this exploratory study emphasize the strong link between stress and relaxation breathing in both respiratory sinus arrhythmia and low frequency heart rate variability and the need for controlling potential covariates for understanding the relationship between HRV and the stress response and providing a basis for hypothesis driven research.

Biofeedback-Assisted Resilience Training for Traumatic and Operational Stress: Preliminary Analysis of a Self-Delivered Digital Health Methodology.

BACKGROUND: Psychological resilience is critical to minimize the health effects of traumatic events. Trauma may induce a chronic state of hyperarousal, resulting in problems such as anxiety, insomnia, or posttraumatic stress disorder. Mind-body practices, such as relaxation breathing and mindfulness meditation, help to reduce arousal and may reduce the likelihood of such psychological distress. To better understand resilience-building practices, we are conducting the Biofeedback-Assisted Resilience Training (BART) study to evaluate whether the practice of slow, paced breathing with or without heart rate variability biofeedback can be effectively learned via a smartphone app to enhance psychological resilience. OBJECTIVE: Our objective was to conduct a limited, interim review of user interactions and study data on use of the BART resilience training app and demonstrate analyses of real-time sensor-streaming data. METHODS: We developed the BART app to provide paced breathing resilience training, with or without heart rate variability biofeedback, via a self-managed 6-week protocol. The app receives streaming data from a Bluetooth-linked heart rate sensor and displays heart rate variability biofeedback to indicate movement between calmer and stressful states. To evaluate the app, a population of military personnel, veterans, and civilian first responders used the app for 6 weeks of resilience training. We analyzed app usage and heart rate variability measures during rest, cognitive stress, and paced breathing. Currently released for the BART research study, the BART app is being used to collect self-reported survey and heart rate sensor data for comparative evaluation of paced breathing relaxation training with and without heart rate variability biofeedback. RESULTS: To date, we have analyzed the results of 328 participants who began using the BART app for 6 weeks of stress relaxation training via a self-managed protocol. Of these, 207 (63.1%) followed the app-directed procedures and completed the training regimen. Our review of adherence to protocol and app-calculated heart rate variability measures indicated that the BART app acquired high-quality data for evaluating self-managed stress relaxation training programs. CONCLUSIONS: The BART app acquired high-quality data for studying changes in psychophysiological stress according to mind-body activity states, including conditions of rest, cognitive stress, and slow, paced breathing.

Workplace victimization risk and protective factors for suicidal behavior among active duty military personnel.

BACKGROUND: Workplace victimization is a potential risk factor for suicidal behaviors (SB) among military personnel that has been largely overlooked. This paper examines both the impact of workplace victimization on reported SB and several potential protective factors associated with such suicidal behaviors in a large sample of active duty soldiers. METHODS: A case-control study was conducted with 71 soldiers who reported SB in the past 12 months, each matched on sociodemographic characteristics to two others without reported suicidal behaviors. A multiple regression model was estimated to assess the effects of risk and protective factors while controlling for other variables. RESULTS: SB was associated with several aspects of victimization, mental health and substance abuse conditions, pain, impulsivity, stressors, negative life events, work-family conflict, active coping behaviors and positive military-related factors. Controlling for other variables, those with SB were more likely to have sought mental health or substance abuse services, to be depressed, anxious, impulsive, and less resilient than non-SB personnel. LIMITATIONS: Study limitations included the use of retrospective self-report data, absence of some known SB predictors, and a population restricted to active duty Army personnel. CONCLUSIONS: SB among active duty personnel is associated with victimization since joining the military and is protected by resiliency. These findings suggest that in addition to the usual mental health factors, these additional predictors should be accounted for in SB intervention and prevention planning for active duty personnel.

PHIT for Duty, a Mobile Application for Stress Reduction, Sleep Improvement, and Alcohol Moderation.

Post-traumatic stress and other problems often occur after combat, deployment, and other military operations. Because techniques such as mindfulness meditation show efficacy in improving mental health, our team developed a mobile application (app) for individuals in the armed forces with subclinical psychological problems as secondary prevention of more significant disease. Based on the Personal Health Intervention Toolkit (PHIT), a mobile app framework for personalized health intervention studies, PHIT for Duty integrates mindfulness-based relaxation, behavioral education in sleep quality and alcohol use, and psychometric and psychophysiological data capture. We evaluated PHIT for Duty in usability and health assessment studies to establish app quality for use in health research. Participants (N = 31) rated usability on a 1 (very hard) to 5 (very easy) scale and also completed the System Usability Scale (SUS) questionnaire (N = 9). Results were (mean ± SD) overall (4.5 ± 0.6), self-report instruments (4.5 ± 0.7), pulse sensor (3.7 ± 1.2), sleep monitor (4.4 ± 0.7), sleep monitor comfort (3.7 ± 1.1), and wrist actigraphy comfort (2.7 ± 0.9). The average SUS score was 85 ± 12, indicating a rank of 95%. A comparison of PHIT-based assessments to traditional paper forms demonstrated a high overall correlation (r = 0.87). These evaluations of usability, health assessment accuracy, physiological sensing, system acceptability, and overall functionality have shown positive results and affirmation for using the PHIT framework and PHIT for Duty application in mobile health research.

Substance use trends among active duty military personnel: findings from the United States Department of Defense Health Related Behavior Surveys, 1980-2005.

AIMS: This study was designed to assess trends in cigarette, illicit drug, and heavy alcohol use among active-duty military personnel from 1980 to 2005 and to examine the influence of socio-demographic changes within the military on patterns of substance use. DESIGN: Substance use prevalence rates were estimated from cross-sectional data obtained from nine self-report surveys administered to more than 150 000 active-duty service members world-wide over a 25-year period. Direct standardization was used to adjust for socio-demographic changes. MEASUREMENTS: Measures included self-reported cigarette use, illicit drug use and heavy alcohol use in the 30 days prior to the survey. Heavy alcohol use was defined as drinking five or more drinks per typical drinking occasion at least once a week in the past 30 days. FINDINGS: Cigarette and illicit drug use among military personnel declined sharply and significantly from 1980 to 1998. Heavy alcohol use decreased in the mid-1980s but was stable from 1988 to 1998. Both cigarette smoking and heavy alcohol use increased significantly between 1998 and 2002 and remained at those levels in 2005. Illicit drug use remained low. Logistic regression analyses indicated that trends were influenced by other factors besides socio-demographic changes across survey years. CONCLUSIONS: The military has made notable progress in decreasing cigarette smoking and illicit drug use, but has made less progress in reducing heavy alcohol use. Additional emphasis should be placed on understanding recent increases in substance use and on planning effective interventions and prevention programs to reduce use in this high-risk population.

Health-Related Coping Behaviors and Mental Health in Military Personnel.

BACKGROUND: Our previous research has highlighted the important link between coping behaviors and mental health symptoms in military personnel. This study seeks to extend these findings by examining each coping behavior and mental health issue individually. This study has four specific aims: (1) test cross-sectional relationships between coping and mental health at baseline and follow-up, (2) examine stability of each variable over time, (3) determine the predictive nature of baseline mental health and coping on subsequent mental health and coping, (4) assess the magnitude of each effect to evaluate the differential predictive value of coping behaviors and mental health symptoms. METHODS: A convenience sample of U.S. Army platoons of the 82nd Airborne was surveyed. We used a two-wave, cross-lagged autoregression design with structural equation modeling to disentangle elements of temporality and to examine the predictive value of mental health status vis-à-vis coping behaviors and vice versa. Separate analyses were performed with each coping strategy and each set of mental health symptoms. This design allowed for the analysis of two synchronous associations (i.e., cross-sectional correlations between the coping strategy and mental health symptoms at each time point), two autoregressive effects (i.e., baseline mental health predicting mental health at follow-up and baseline coping predicting coping at follow-up), and two cross-lagged effects (i.e., baseline coping strategy predicting mental health at follow-up and baseline mental health predicting follow-up coping). RESULTS: Results of descriptive statistics revealed that the most frequently reported coping behavior was thinking of a plan to solve the problem, followed by talking to a friend, engaging in a hobby, and exercising or playing sports. The least often endorsed coping behaviors were smoking marijuana or using illicit drugs and thinking about hurting or killing oneself, followed by having a drink or lighting up a cigarette. We verified many cross-sectional relationships between coping behaviors and mental health symptoms. Specifically, talking to a friend, exercising or playing sports, engaging in a hobby, and thinking of a plan were associated with fewer anxiety, perceived stress, and depression symptoms, whereas smoking a cigarette, having a drink, and thinking about hurting or killing oneself were associated with more anxiety, perceived stress, and depressive symptoms. Marijuana and illicit drug use was also associated with higher depressive symptoms. Saying a prayer was not significantly related to mental health. Only four cross-lagged effects were significant. Those who reported more depressive symptoms at Time 1 reported talking to friends and family less and exercising or playing sports less as coping behaviors at Time 2. Baseline perceived stress predicted less likelihood of engaging in a hobby at follow-up, whereas exercising or playing sports as a coping behavior at baseline predicted lower perceived stress at follow-up. DISCUSSION: This study expands the evidence for the associations between coping behaviors and psychological health or distress to specific mental health symptoms, particularly in military service members, and provides comparisons of magnitude of each association. Clinically, this knowledge is critical to more efficiently target behaviors with the greatest associations to mental health in military personnel.

Stress, mental health, and job performance among active duty military personnel: findings from the 2002 Department of Defense Health-Related Behaviors Survey.

This study examined the extent to which high levels of occupational and family stress were associated with mental health problems and productivity loss among active duty military personnel. We analyzed data from the 2002 Department of Defense Survey of Health-Related Behaviors among Military Personnel, which provided extensive population-based information on 12,756 active duty personnel in all branches of the military worldwide. Military personnel reported higher levels of stress at work than in their family life. The personnel reporting the highest levels of occupational stress were those 25 or younger, those who were married with spouses not present, and women. Personnel with high levels of stress had significantly higher rates of mental health problems and productivity loss than those with less stress. We recommend that prevention and intervention efforts geared toward personnel reporting the highest levels of stress be given priority for resources in this population.

Help-Seeking Behaviors Among Active-Duty Military Personnel: Utilization of Chaplains and Other Mental Health Service Providers.

Military chaplains not only conduct religious services, but also provide counseling and spiritual support to military service members, operating as liaisons between soldiers and mental health professionals. In this study, active-duty soldiers (N = 889) reported help-seeking behaviors and mental health. Using logistic regressions, we describe the issues for which soldiers reported seeking help, then outline the characteristics of those who are most likely to seek help from a chaplain. Of the soldiers who sought help from a chaplain within the previous year, 29.9% reported high levels of combat exposure, 50.8% screened positive for depression, 39.1% had probable PTSD, and 26.6% screened positive for generalized anxiety disorder. The participant's unit firing on the enemy, personally firing on the enemy, and seeing dead bodies or human remains predicted seeing a chaplain. Future research should examine ways to engage soldiers who have had more combat experiences with the chaplain community to address spiritual issues.

Gender Differences in Posttraumatic Stress Disorder and Help Seeking in the U.S. Army.

BACKGROUND: Inconsistent findings between studies of gender differences in mental health outcomes in military samples have left open questions of differential prevalence in posttraumatic stress disorder (PTSD) among all United States Army soldiers and in differential psychosocial and comorbid risk and protective factor profiles and their association with receipt of treatment. METHODS: This study assesses the prevalence and risk factors of screening positive for PTSD for men and women based on two large, population-based Army samples obtained as part of the 2005 and 2008 U.S. Department of Defense Surveys of Health Related Behaviors among Active Duty Military Personnel. RESULTS: The study showed that overall rates of PTSD, as measured by several cutoffs of the PTSD Checklist, are similar between active duty men and women, with rates increasing in both men and women between the two study time points. Depression and problem alcohol use were strongly associated with a positive PTSD screen in both genders, and combat exposure was significantly associated with a positive PTSD screen in men. Overall, active duty men and women who met criteria for PTSD were equally likely to receive mental health counseling or treatment, though gender differences in treatment receipt varied by age, race, social support (presence of spouse at duty station), history of sexual abuse, illness, depression, alcohol use, and combat exposure. CONCLUSIONS: The study demonstrates that the prevalence of PTSD as well as the overall utilization of mental health services is similar for active duty men compared with women. However, there are significant gender differences in predictors of positive PTSD screens and receipt of PTSD treatment.

Toward Preventing Post-Traumatic Stress Disorder: Development and Testing of a Pilot Predeployment Stress Inoculation Training Program.

The objective of this pilot study was to design, develop, and evaluate a predeployment stress inoculation training (PRESIT) preventive intervention to enable deploying personnel to cope better with combat-related stressors and mitigate the negative effects of trauma exposure. The PRESIT program consisted of three predeployment training modules: (1) educational materials on combat and operational stress control, (2) coping skills training involving focused and relaxation breathing exercises with biofeedback, and (3) exposure to a video multimedia stressor environment to practice knowledge and skills learned in the first two modules. Heart rate variability assessed the degree to which a subset of participants learned the coping skills. With a cluster randomized design, data from 351 Marines randomized into PRESIT and control groups were collected at predeployment and from 259 of these who responded to surveys on return from deployment. Findings showed that the PRESIT group reduced their physiological arousal through increased respiratory sinus arrhythmia during and after breathing training relative to controls. Logistic regression, corrected for clustering at the platoon level, examined group effects on post-traumatic stress disorder (PTSD) as measured by the Post-traumatic Stress Checklist after controlling for relevant covariates. Results showed that PRESIT protected against PTSD among Marines without baseline mental health problems. Although limited by a small number of participants who screened positive for PTSD, this study supports the benefits of PRESIT as a potential preventive strategy in the U.S. military personnel.