This page contains information on the military and veteran research publications from the members of the NIVHWS. This information will be updated regularly. The official NIVHWS reports can be found here.

Click on any publication title below for further information and a link to the full article. If the full text is unavailable for any of these please contact a member of the research team.


A network analysis of DSM-5 posttraumatic stress disorder and functional impairment in UK treatment-seeking veterans

Ross, J., Murphy, D., & Armour, C.

Network analysis is a relatively new methodology for studying psychological disorders. It focuses on the associations between individual symptoms which are hypothesized to mutually interact with each other. The current study represents the first network analysis conducted with treatment-seeking military veterans in UK. The study aimed to examine the network structure of posttraumatic stress disorder (PTSD) symptoms and four domains of functional impairment by identifying the most central (i.e., important) symptoms of PTSD and by identifying those symptoms of PTSD that are related to functional impairment. Participants were 331 military veterans with probable PTSD. In the first step, a network of PTSD symptoms based on the PTSD Checklist for DSM-5 was estimated. In the second step, functional impairment items were added to the network. The most central symptoms of PTSD were recurrent thoughts, nightmares, negative emotional state, detachment and exaggerated startle response. Functional impairment was related to a number of different PTSD symptoms. Impairments in close relationships were associated primarily with the negative alterations in cognitions and mood symptoms and impairments in home management were associated primarily with the reexperiencing symptoms. The results are discussed in relation to previous PTSD network studies and include implications for clinical practice.


Typologies of adverse childhood experiences and their relationship to incarceration in U.S. military veterans

Ross, J., Waterhouse-Bradley, B., Contractor, A. A., & Armour, C.

Numerous studies have reported that adverse childhood experiences (ACEs) are associated with negative psychosocial outcomes in adulthood, but no study has examined the different typologies of ACEs and the relationship of these with adult incarceration in military veterans. The current study used latent class analysis to examine the existence of different childhood maltreatment and household dysfunction typologies in a sample of U.S. military veterans identified through the National Epidemiological Survey on Alcohol and Related Conditions-III (NESARC-III). A total of 60.73% of veterans reported one or more ACEs. Four latent classes were identified and were named Low adversities, Moderate maltreatment with high household substance use, Severe maltreatment with moderate household dysfunction and Severe multi-type adversities. Relative to the Low adversities class, the three maltreatment/dysfunction classes had significantly elevated odds ratios (1.72 – 2.29) for adult incarceration, when controlling for sociodemographic characteristics and alcohol and drug use. The results point to the importance of examining childhood risk factors for incarceration and suggest that a certain sub-group of military personnel who are about to transition into the civilian life may need additional support to adjust and live successful lives.


Evaluating the stability of DSM-5 PTSD symptom network structure in a national sample of U.S. military veterans

Von Stockert, S. H. H., Fried, E. I., Armour, C., & Pietrzak, R. H.

Background: Previous studies have used network models to investigate how PTSD symptoms associate with each other. However, analyses examining the degree to which these networks are stable over time, which are critical to identifying symptoms that may contribute to the chronicity of this disorder, are scarce. In the current study, we evaluated the temporal stability of DSM-5 PTSD symptom networks over a three-year period in a nationally representative sample of trauma-exposed U.S. military veterans.

Methods: Data were analyzed from 611 trauma-exposed U.S. military veterans who participated in the National Health and Resilience in Veterans Study (NHRVS). We estimated regularized partial correlation networks of DSM-5 PTSD symptoms at baseline (Time 1) and at three-year follow-up (Time 2), and examined their temporal stability.

Results: Evaluation of the network structure of PTSD symptoms at Time 1 and Time 2 using a formal network comparison indicated that the Time 1 network did not differ significantly from the Time 2 network with regard to network structure (p = 0.12) or global strength (sum of all absolute associations, i.e. connectivity; p = 0.25). Centrality estimates of both networks (r = 0.86) and adjacency matrices (r = 0.69) were highly correlated. In both networks, avoidance, intrusive, and negative cognition and mood symptoms were among the more central nodes. Limitations This study is limited by the use of a self-report instrument to assess PTSD symptoms and recruitment of a relatively homogeneous sample of predominantly older, Caucasian veterans.

Conclusion: Results of this study demonstrate the three-year stability of DSM-5 PTSD symptom network structure in a nationally representative sample of trauma-exposed U.S. military veterans. They further suggest that trauma-related avoidance, intrusive, and dysphoric symptoms may contribute to the chronicity of PTSD symptoms in this population.


Exploring optimum cut-off scores to screen for probable posttraumatic stress disorder within a sample of UK treatment-seeking veterans

Murphy, D., Ross, J., Ashwick, R., Armour, C., & Busuttil, W.

Background: Previous research exploring the psychometric properties of the scores of measures of posttraumatic stress disorder (PTSD) suggests there is variation in their functioning depending on the target population. To date, there has been little study of these properties within UK veteran populations.

Objective: This study aimed to determine optimally efficient cut-off values for the Impact of Event Scale-Revised (IES-R) and the PTSD Checklist for DSM-5 (PCL-5) that can be used to assess for differential diagnosis of presumptive PTSD.

Methods: Data from a sample of 242 UK veterans assessed for mental health difficulties were analysed. The criterion-related validity of the PCL-5 and IES-R were evaluated against the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5). Kappa statistics were used to assess the level of agreement between the DSM-IV and DSM-5 classification systems. Results: The optimal cut-off scores observed within this sample were 34 or above on the PCL-5 and 46 or above on the IES-R. The PCL-5 cut-off is similar to the previously reported values, but the IES-R cut-off identified in this study is higher than has previously been recommended. Overall, a moderate level of agreement was found between participants screened positive using the DSM-IV and DSM-5 classification systems of PTSD.

Conclusions: Our findings suggest that the PCL-5 and IES-R can be used as brief measures within veteran populations presenting at secondary care to assess for PTSD. The use of a higher cut-off for the IES-R may be helpful for differentiating between veterans who present with PTSD and those who may have some symptoms of PTSD but are sub-threshold for meeting a diagnosis. Further, the use of more accurate optimal cut-offs may aid clinicians to better monitor changes in PTSD symptoms during and after treatment.


The 7-factor hybrid model of DSM-5 PTSD symptoms and alcohol consumption and consequences in a national sample of trauma-exposed veterans

Claycomb E,M., Charak, R., Durham, T. A., Armour, C., Lv, X., Southwick, S., Elhai, J. D., & Pietrzak, R.

The purpose of the present study was to investigate associations between the 7-factor hybrid model of DSM-5 posttraumatic stress disorder (PTSD) symptoms, which includes intrusions, avoidance, negative affect, anhedonia, externalizing behaviors, anxious arousal, and dysphoric arousal symptoms, and alcohol consumption and consequences. A nationally representative sample of 916 trauma-exposed U.S. military veterans were administered the Trauma History Screen, PTSD Checklist-5, and Alcohol Use Disorders Identification Test. Confirmatory factor analyses were conducted to determine associations between the 7-factor hybrid model of PTSD symptoms, and alcohol consumption and consequences. Results revealed that lifetime dysphoric arousal (r = 0.31), negative affect (r = 0.30), and anhedonia (r = 0.29) symptom clusters were most strongly associated with past-year alcohol consequences. No significant associations were observed for alcohol consumption. While the cross-sectional study design does not allow one to ascertain causative associations between PTSD factors and alcohol consumption and consequences, results generally align with the self-medication hypothesis, as PTSD factors reflecting internalizing were most strongly related to alcohol-related consequences. These results underscore the importance of assessing for alcohol use problems in veterans who score highly on PTSD symptoms reflecting internalizing symptomatology.


A Network Analysis of DSM-5 posttraumatic stress disorder symptoms and correlates in U.S. military veterans

Armour, C., Fried, E. I., Deserno, M. K., Tsai, J., & Pietrzak, R.H.

Objective: Recent developments in psychometrics enable the application of network models to analyze psychological disorders, such as PTSD. Instead of understanding symptoms as indicators of an underlying common cause, this approach suggests symptoms co-occur in syndromes due to causal interactions. The current study has two goals: (1) examine the network structure among the 20 DSM-5 PTSD symptoms, and (2) incorporate clinically relevant variables to the network to investigate whether PTSD symptoms exhibit differential relationships with suicidal ideation, depression, anxiety, physical functioning/quality of life (QoL), mental functioning/QoL, age, and sex.

Method: We utilized a nationally representative U.S. military veteran’s sample; and analyzed the data from a subsample of 221 veterans who reported clinically significant DSM-5 PTSD symptoms. Networks were estimated using state-of-the-art regularized partial correlation models. Data and code are published along with the paper.

Results: The 20-item DSM-5 PTSD network revealed that symptoms were positively connected within the network. Especially strong connections emerged between nightmares and flashbacks; blame of self or others and negative trauma-related emotions, detachment and restricted affect; and hypervigilance and exaggerated startle response. The most central symptoms were negative trauma-related emotions, flashbacks, detachment, and physiological cue reactivity. Incorporation of clinically relevant covariates into the network revealed paths between self-destructive behavior and suicidal ideation; concentration difficulties and anxiety, depression, and mental QoL; and depression and restricted affect.

Conclusion: These results demonstrate the utility of a network approach in modeling the structure of DSM-5 PTSD symptoms, and suggest differential associations between specific DSM-5 PTSD symptoms and clinical outcomes in trauma survivors. Implications of these results for informing the assessment and treatment of this disorder, are discussed.


The Health and Well-being of Military Drone Operators and Intelligence Analysts: A Systematic Review

Armour, C., & Ross, J.

Objectives: The aim of this study was to systematically review the existing research on the health and well-being of military drone operators and intelligence analysts in order to provide an overview of research and identify gaps in this area.

Methods: Six literature databases and two databases containing unclassified military reports were searched for relevant papers produced between January 1996 to May 2016. The search criteria were broad to allow for the identification of all relevant studies on the topic.

Results: Fifteen studies met the inclusion criteria; all of which were conducted in the U.S. with the U.S. Air Force personnel. The main sources of occupational stress reported by participants across the studies were operational. The rates of mental health diagnoses, including PTSD, were low, but levels of psychological distress were higher in drone and intelligence operators than in comparison groups. Fatigue emerged as a significant concern.

Conclusions: It is important that future studies examine a variety of mental and physical health outcomes. The health and well-being of drone operators and intelligence analysts should be studied not just in the U.S., but also in other countries that are using drones for military purposes.


Dissociative subtype of DSM-5 posttraumatic stress disorder in U.S. veterans

Tsai, J., Armour, C., Southwick, S. M., & Pietrzak, R. H.

The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) formally introduced a dissociative subtype of posttraumatic stress disorder (PTSD). This study examined the proportion of U.S. veterans with DSM-5 PTSD that report dissociative symptoms; and compared veterans with PTSD with and without the dissociative subtype and trauma-exposed controls on sociodemographics, clinical characteristics, and quality of life. Multivariable analyses were conducted on a nationally representative sample of 1484 veterans from the National Health and Resilience in Veterans Study (second baseline survey conducted September–October, 2013). Of the 12.0% and 5.2% of veterans who screened positive for lifetime and past-month DSM-5 PTSD, 19.2% and 16.1% screened positive for the dissociative subtype, respectively. Among veterans with PTSD, those with the dissociative subtype reported more severe PTSD symptoms, comorbid depressive and anxiety symptoms, alcohol use problems, and hostility than those without the dissociative subtype. Adjusting for PTSD symptom severity, those with the dissociative subtype continued to report more depression and alcohol use problems. These results underscore the importance of assessing, monitoring, and treating the considerable proportion of veterans with PTSD and dissociative symptoms.


Armour, C., Contractor, A., Elhai, J.D., Stringer, M., Lyle, G., Forbes, D., & Richardson, J.D.

Posttraumatic stress disorder (PTSD) has been consistently reported as being highly comorbid with major depressive disorder (MDD) and as being associated with health related functional impairment (HRF). We used archival data from 283 previously war-zone deployed Canadian veterans. Latent profile analysis (LPA) was used to uncover patterns of PTSD and MDD comorbidity as measured via the PTSD Checklist-Military version (PCL-M) and the Patient Health Questionnaire-9 (PHQ-9). Individual membership of latent classes was used in a series of one-way ANOVAs to ascertain group differences related to HRF as measured via the Short-Form-36 Health Survey (SF-36). LPA resulted in three discrete patterns of PTSD and MDD comorbidity which were characterized by high symptoms of PTSD and MDD, moderate symptoms, and low symptoms. All ANOVAs comparing class membership on the SF-36 subscales were statistically significant demonstrating group differences across levels of HRF. The group with the highest symptoms reported the worst HRF followed by the medium and low symptom groups. These findings are clinically relevant as they demonstrate the need for continual assessment and targeted treatment of co-occurring PTSD and MDD.


The role of locus of control and coping style in predicting longitudinal PTSD-trajectories after combat exposure

Karstoft, K.I., Armour, C., Elklit, A., & Solomon, Z.

While longitudinal posttraumatic stress responses are known to be heterogeneous, little is known about predictors of those responses. We investigated if locus of control (LOC) and coping style are associated with long-term PTSD-trajectories after exposure to combat. Six hundred and seventy five Israeli soldiers with or without combat stress reaction (CSR) from the Lebanon war were assessed 1, 2, and 20 years after the war. Combat exposure, LOC, and coping style were then investigated as covariates of the trajectories of resilience, recovery, delayed onset, and chronicity. Symptomatic trajectories in the CSR and the non-CSR group were significantly associated to varying degrees with perceived life threat during combat (ORs: 1.76–2.53), internal LOC (0.77–0.87), emotional coping style (0.28–0.34), and low use of problem-focused coping (2.12–3.11). In conclusion, assessment of LOC and coping can aid prediction of chronic PTSD outcomes of combat exposure.


Dimensional structure of DSM-5 posttraumatic stress symptoms: Results from the National Health and Resilience in Veterans Study

Tsai, J., Harpaz-Rotem, I., Armour, C., Southwick, S. M., Krystal, J. H., & Pietrzak, R. H.

Objective: To evaluate the prevalence of DSM-5 posttraumatic stress disorder (PTSD) and factor structure of PTSD symptomatology in a nationally representative sample of US veterans and examine how PTSD symptom clusters are related to depression, anxiety, suicidal ideation, hostility, physical and mental health–related functioning, and quality of life.

Method: Data were analyzed from the National Health and Resilience in Veterans Study, a nationally representative survey of 1,484 US veterans conducted from September through October 2013. Confirmatory factor analyses were conducted to evaluate the factor structure of PTSD symptoms, and structural equation models were constructed to examine the association between PTSD symptom clusters and external correlates.

Results: 12.0% of veterans screened positive for lifetime PTSD and 5.2% for past-month PTSD. A 5-factor dysphoric arousal model and a newly proposed 6-factor model both fit the data significantly better than the 4-factor model of DSM-5. The 6-factor model fit the data best in the full sample, as well as in subsamples of female veterans and veterans with lifetime PTSD. The emotional numbing symptom cluster was more strongly related to depression (P < .001) and worse mental health–related functioning (P < .001) than other symptom clusters, while the externalizing behavior symptom cluster was more strongly related to hostility (P < .001).

Conclusions: A total of 5.2% of US veterans screened positive for past-month DSM-5 PTSD. A 6-factor model of DSM-5 PTSD symptoms, which builds on extant models and includes a sixth externalizing behavior factor, provides the best dimensional representation of DSM-5PTSD symptom clusters and demonstrates validity in assessing health outcomes of interest in this population.


Community integration after deployment to Afghanistan: a longitudinal investigation of Danish soldiers

Karstoft, K.I., Madsen, T., Andersen, S. B., Armour, C., & Bertelsen, M. (2015)

Objective: In the years following military deployment, soldiers may experience problems integrating into the community. However, little is known about the nature and prevalence of these problems and if they relate to posttraumatic symptomatology.

Methods: In a prospective, longitudinal study of Danish soldiers deployed to Afghanistan in 2009 (N = 743), we assessed community reintegration difficulties 2.5 years after home coming (study sample: N = 454). Furthermore, symptoms of posttraumatic stress disorder (PTSD) were assessed before, during, and after deployment. Trajectories of PTSD symptoms from a previously published latent growth mixture modeling analysis were used to address whether community reintegration difficulties differ as a result of course and level of PTSD symptoms.

Results: Between 3.6 and 18.0 % reported to have some, a lot, or extreme difficulties in reintegration domains such as interpersonal functioning, productivity, community involvement, and self-care. Mean level of reintegration difficulties differed significantly across six PTSD symptom trajectories (range 6.35–36.00); with more symptomatic trajectories experiencing greater community reintegration difficulties.

Conclusions: Reintegration difficulties after deployment are present in less than 20 % of Danish soldiers who return from Afghanistan. Difficulties are greater in individuals who follow symptomatic PTSD trajectories in the first years following deployment than in those who follow a low-stable trajectory with no or few symptoms.


Functional significance of a novel 7-factor model of DSM-5 PTSD symptoms: Results from the National Health and Resilience in Veterans Study

Pietrzak, R. H., Tsai, J., Armour, C., Mota, N., Harpaz-Rotem, I., & Southwick, S. M.

Background: While posttraumatic stress disorder (PTSD) symptoms in the recently published Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) are clustered into four factors, emerging confirmatory factor analytic studies suggest that this disorder is best characterized by seven symptom clusters, including re-experiencing, avoidance, negative affect, anhedonia, externalizing behaviors, and anxious and dysphoric arousal symptoms. To date, however, data are lacking regarding the relation between this novel model of DSM-5 PTSD symptoms and measures of clinical significance in this population (e.g., functioning).

Methods: Using data from the National Health and Resilience in Veterans Study (NHRVS), a contemporary, nationally representative sample of 1484 U.S. veterans, we evaluated clinical and functional correlates of a novel 7-factor model of DSM-5 PTSD symptoms.

Results: Differential patterns of associations were observed between DSM-5 PTSD symptom clusters, and psychiatric comorbidities, suicidal ideation, hostility, and functioning and quality of life. Anhedonia symptoms, in particular, were strongly related to current depression, as well as reduced mental functioning and quality of life. Externalizing behaviors were most strongly related to hostility, supporting the convergent validity of this construct.

Limitations: Cross-sectional design and employment of self-report measures.

Conclusions: These results suggest that a more refined 7-factor model of DSM-5 PTSD symptoms may provide greater specificity in understanding associations with comorbid psychopathology, suicidal ideation, and functioning and quality of life in U.S. veterans. They further suggest that prevention and treatment efforts that target distinct aspects of the PTSD phenotype may be more effective in mitigating key clinical and functional outcomes in this population.

Richardson, J. D., Contractor, A., Armour, C., St. Cyr, K. C., Elhai, J. D., & Sareen, J.

Objective: Posttraumatic stress disorder (PTSD) is a significant psychiatric condition that may result from exposure to combat; it has been associated with severe psychosocial dysfunction. This study examined the predictors of long-term treatment outcomes in a group of veterans with military-related PTSD.

Method: The study consisted of a retrospective chart review of 151 consecutive veterans treated at an outpatient clinic for veterans with psychiatric disorders resulting from their military operations between January 2002 and May 2012. The diagnosis of PTSD was made using the Clinician-Administered PTSD Scale. As part of treatment as usual, all patients completed the PTSD Checklist-Military version and Beck Depression Inventory (BDI-II) at intake and at each follow-up appointment, the Short-Form Health Survey (SF-36) at intake, and either the SF-36 or the 12-item Short-Form Health Survey at follow-up. All patients received psychoeducation about PTSD and combined pharmacotherapy and psychotherapy.

Results: Analyses demonstrated a significant and progressive improvement in PTSD severity over the 2-year period ([n = 117] Yuan-Bentler χ240 = 221.25, P < .001). We found that comorbid depressive symptom severity acted as a significant predictor of PTSD symptom decline (β = −.44, SE = .15, P = .004). However, neither alcohol misuse severity nor the number of years with PTSD symptoms (chronicity) was a significant predictor of treatment response.

Conclusions: This study highlights the importance of treating comorbid symptoms of depression aggressively in veterans with military-related PTSD. It also demonstrates that significant symptom reduction, including loss of probable PTSD diagnosis, is possible in an outpatient setting for veterans with chronic military-related PTSD.


Long term trajectories of PTSD in veterans: the role of social resources

Karstoft, K. I., Armour, C., Elklit, A., & Solomon, Z.

Objective: To (1) identify long-term trajectories of combat-induced posttraumatic stress disorder (PTSD) symptoms over a 20-year period from 1983 to 2002 in veterans with and without combat stress reaction (CSR) and (2) identify social predictors of these trajectories.

Method: A latent growth mixture modeling analysis on PTSD symptoms was conducted to identify PTSD trajectories and predictors. PTSD was defined according to DSM-III and assessed through the PTSD Inventory. Israeli male veterans with (n = 369) and without (n = 306) CSR were queried at 1, 2, and 20 years after war about combat exposure, military unit support, family environment, and social reintegration.

Results: For both study groups, we identified 4 distinct trajectories with varying prevalence across groups: resilience (CSR = 34.4%, non-CSR = 76.5%), recovery (CSR = 36.3%, non-CSR = 10.5%), delayed onset (CSR = 8.4%, non-CSR = 6.9%), and chronicity (CSR = 20.9%, non-CSR = 6.2%). Predictors of trajectories in both groups included perception of war threat (ORs = 1.59-2.47, P values ≤ .30), and negative social reintegration (ORs = 0.24-0.51, P values ≤ .047). Social support was associated with symptomatology only in the CSR group (ORs = 0.40-0.61, P values ≤ .045), while family coherence was predictive of symptomatology in the non-CSR group (OR = 0.76, P = .015) but not in the CSR group.

Conclusions: Findings confirmed heterogeneity of long-term sequelae of combat, revealing 4 trajectories of resilience, recovery, delay, and chronicity in veterans with and without CSR. Symptomatic trajectories were more prevalent for the CSR group, suggesting that acute functional impairment predicts pathological outcomes. Predictors of symptomatic trajectories included perceived threat and social resources at the family, network, and societal levels.