Publication year
2015
Citation Title
The relationship between course of PTSD symptoms in deployed U.S. Marines and degree of combat exposure.
Journal Name
Journal of Traumatic Stress
Journal Volume
28
Issue Number
1
Page Numbers
73-78
DOI
10.1002/jts.21988
Summary
Male Marines participated in a study examining the longitudinal course of posttraumatic stress disorder (PTSD) symptoms after combat exposure. Marines were split into three groups based on level of combat exposure (low, medium, and high). Distinct trajectories within each level of combat exposure emerged which represented fluctuations in PTSD symptoms over time.
Key Findings
Marines with higher levels of combat exposure experienced a temporary clinically significant increase in PTSD symptoms over the deployment cycle, followed by a gradual bounce back.
Marines with the lowest combat exposure had consistently low PTSD symptoms over time.
Levels of PTSD symptoms shortly after homecoming were high across all combat exposure groups; symptoms decreased considerably in the less exposed group, but less sharply in the middle and high exposure groups.
Across groups, a small percentage of Marines experienced new-onset PTSD, meaning symptoms emerged over time after homecoming.
Implications for Program Leaders
Provide classes for Service members, explaining how PTSD symptoms can fluctuate and develop over time
Offer support groups for Service members, giving them opportunities to exchange social support
Create classes for family members and children of Service members with PTSD, teaching how they can understand and support their Service member
Implications for Policy Makers
Recommend screening all deploying Service members for PTSD prior to deployment
Urge continued support of family members whose Service member is living with PTSD
Recommend training for community providers to educate them about unique factors that contribute to mental health symptoms for Service members and their families
Methods
A cohort of male Marines enrolled in the Marine Resiliency Study were selected due to their deployment to Afghanistan during a time of heavy unrest and exposure to heavy combat.
Marines were evaluated one month before deployment and one, five, and eight months post deployment; 46% completed the eight month assessment.
Warzone exposure was assessed via questionnaire. PTSD was assessed using a structured clinical interview.
Statistical analyses were used to test whether distinct trajectories of PTSD symptoms were presented in the groups with different levels of combat exposure.
Participants
Six hundred seventeen male Marines participated in the study.
The average age of the sample was 23.2 years (SD = 3.8 years), and 41% were married.
Ninety-eight percent of the sample was enlisted, and 48% had at least one prior deployment.
Racial/ethnic composition of the sample was as follows: 83% White, 25% Latino/Latina, and 6% Asian-American.
Limitations
The combat exposure measure assessed frequency but not severity.
The sample consisted of male Marines, and these findings may not generalize to other groups.
The follow-up period was relatively short; findings might change with a longer time frame.
No information on treatment for PTSD was collected which could explain some of the changes over time.
Avenues for Future Research
Gather data on the type of combat exposure and its relationship with PTSD symptom trajectories among Service members
Examine the predictors of the trajectories with larger sample sizes
Explore the course of PTSD symptoms among female Service members
Focus
Marines
Target Population
Population Focus
Military Branch
Military Component
Abstract
Large cohort studies suggest that most military personnel experience minimal posttraumatic stress disorder (PTSD) symptoms following warzone deployment, an outcome often labeled resilience. Very low symptom levels, however, may be a marker for low exposure, not resilience, which requires relatively high-magnitude or high-frequency stress exposure as a precondition. We used growth mixture modeling (GMM) to examine the longitudinal course of lifetime PTSD symptoms following combat exposure by disaggregating deployed U.S. Marines into upper, middle, and lower tertiles of combat exposure. All factor models fit the data well; Tucker-Lewis Index (TLI) and comparative fit index (CFI) values ranged from .91 to .97. Three distinct trajectories best explained the data within each tertile. The upper tertile comprised True Resilience (73.2%), New-Onset Symptoms (18.3%), and Pre-existing Symptoms (8.5%) trajectories. The middle tertile also comprised True Resilience (74.5%), New-Onset Symptoms (16.1%), and Pre-existing Symptoms (9.4%) trajectories. The lower tertile comprised Artifactual Resilience (86.3%), Pre-existing Symptoms (7.6%), and New-Onset Symptoms (6.1%) trajectories. True Resilience involved a clinically significant symptom increase followed by a return to baseline, whereas Artifactual Resilience involved consistently low symptoms. Conflating artifactual and true resilience may inaccurately create the expectation of persistently low symptoms regardless of warzone exposure.
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