Is inflammatory change associated with psychological risk and resilience in high-risk military personnel?

In military populations, the potential for under-reporting of Post-traumatic Stress Disorder (PTSD) symptoms and challenges in recognising early changes can make it difficult to detect an emerging disorder. However, early identification of PTSD symptoms would improve opportunities for intervention, and potentially reduce the likelihood of chronic mental health problems. This study explored if changes in levels of inflammation, measured by C reactive protein (CRP) and interleukin 6 (IL-6), were associated with the onset of psychological symptoms associated with PTSD. It also examined if changes in inflammation over time contributed to psychological risk and resilience, which was defined by psychological reactivity to deployment-related combat exposures. Participants were special forces personnel who completed psychological self-report questionnaires and had measures of CRP and IL-6 taken pre and post deployment. Regression analysis was used to examine how psychological symptoms predicted change in inflammation, and Analysis of Variance (ANOVA) were used to examine differences between identified subgroups. Results identify this population as having high levels of combat and trauma exposures, with low-level psychological symptoms. The results also identified a decrease in CRP and an increase in IL-6 over time. A significant difference in inflammation was identified between subgroups (p<0.05). An association between inflammatory markers and subthreshold symptoms related to anger (p<0.01) and sleep (p<0.05) was also identified. These preliminary findings suggest inflammatory markers may help to identify adaptive responses post deployment. In addition, low-level increases in inflammatory markers may be associated with subthreshold PTSD symptoms. These findings offer potential insights for prevention, early identification and treatment in military and veteran populations.

Bennett N ，Lawrence-Wood E ，McFarlane A 《-》

Identifying psychological risk and resilience in high-risk military personnel.

Combat exposure has been associated with the emergence of post-traumatic stress disorder (PTSD) symptoms in military personnel; however, not all veterans are negatively impacted by their operational experience. In many instances, the absence of symptoms following operational service is attributed to resilience. This study explored the construct of resilience by examining the relationship between levels of deployment-related exposures and psychological symptoms, as well as identifying factors that may contribute to resilience and emerging risk. Participants were special forces personnel who completed self-report questionnaires 1 month before deployment and 4 months post deployment. Subgroups were created based on psychological reactivity to deployment exposures, representing risk, vulnerability and resilience. Regression analysis assessed the contribution of factors that were predictive of risk or resilience groups specifically. Results showed the overall levels of psychological reactivity in this population post deployment were low; however, differences between risk and resilience subgroups were found. Subthreshold indicators of psychological reactivity, as well as deployment factors such as increased deployment frequency and time spent away from home, were found to contribute to differences between risk and resilient trajectories. Findings reflect a military population with low psychological symptoms despite high trauma exposure. However, subtle underlying differences between subgroups suggest that the early identification of risk and emerging trajectories is possible. Risk and resilience in military populations needs to consider subthreshold indicators and individual differences over time.

Bennett N ，Lawrence-Wood E ，McFarlane A 《-》

Assessment of plasma C-reactive protein as a biomarker of posttraumatic stress disorder risk.

Eraly SA ，Nievergelt CM ，Maihofer AX ，Barkauskas DA ，Biswas N ，Agorastos A ，O'Connor DT ，Baker DG ，Marine Resiliency Study Team ... -  《-》

Sleep restoration is associated with reduced plasma C-reactive protein and depression symptoms in military personnel with sleep disturbance after deployment.

Deployed military personnel are vulnerable to chronic sleep disturbance, which is highly comorbid with post-traumatic stress disorder (PTSD) and depression, as well as declines in health-related quality of life (HRQOL). Inflammation is associated with HRQOL declines and sleep-related comorbidities; however, the impact of sleep changes on comorbid symptoms and inflammation in this population is unknown. In this observational study, we examined the relationship between reported sleep changes and concentrations of inflammatory biomarkers, interleukin 6 (IL-6), and C-reactive protein (CRP) in peripheral blood. The sample was dichotomized into two groups: (1) decrease in Pittsburgh Sleep Quality Index (PSQI; restorative sleep) and (2) no change or increase in PSQI (no change). Mixed between-within subjects analysis of variance tests were used to determine group differences on changes of inflammation and comorbid symptoms. In our sample of 66 recently deployed military personnel with insomnia, 34 participants reported restorative sleep whereas 32 reported no sleep changes. The two groups did not differ in demographic or clinical characteristics, with the exception of PTSD diagnosis at baseline. The restorative sleep group had significant reductions in CRP concentrations and depression symptoms, as well as reduced fatigue and improvements in emotional well-being, social functioning, and physical functioning at follow-up. Military personnel who report sleep restoration after deployment have reduced CRP concentrations, decreased severity of depression, and improved HRQOL. These findings suggest that treatment for sleep disturbances may be associated with improvements in mental and physical health, thereby supporting continued study in this line of research.

Heinzelmann M ，Lee H ，Rak H ，Livingston W ，Barr T ，Baxter T ，Scattergood-Keepper L ，Mysliwiec V ，Gill J ... -  《-》

Lower health related quality of life in U.S. military personnel is associated with service-related disorders and inflammation.

Military personnel who have combat exposures are at increased risk for the service-related disorders of post-traumatic stress disorder (PTSD), depression, sleep disturbances and decreased health related quality of life (HRQOL). Those with a traumatic brain injury (TBI) are at even greater risk. Inflammation is associated with these disorders and may underlie the risk for health declines. We evaluated 110 recently deployed, military personnel presenting with sleep disturbances for service-related disorders (TBI, PTSD, and depression) as well as HRQOL. ANOVA models were used to examine differences among military personnel with two or more service-related disorders (high comorbid group), or one or no disorders (low comorbid group). Logistic regression models were used to determine associations among interleukin-6 (IL-6) to HRQOL and service-related disorders. Approximately one-third of the sample had two or more service-related disorders. HRQOL was lower and IL-6 concentrations were higher in military personnel with PTSD or depression, with the most profound differences in those with more service-related disorders, regardless of sleep disorder. Having symptoms of depression and PTSD resulted in a 3.5-fold risk to be in the lower quartile of HRQOL and the highest quartile of IL-6. In a linear regression model, 41% of the relationship between HRQOL and IL-6 concentrations was mediated by PTSD and depression. Military personnel with PTSD and depression are at high risk for lower HRQOL, and higher IL-6 concentrations. Comprehensive treatment is required to address co-occurring service-related disorders in military personnel to promote health and well-being.

Gill J ，Lee H ，Barr T ，Baxter T ，Heinzelmann M ，Rak H ，Mysliwiec V ... -  《-》