Title:
The role of stress sensitization in progression of posttraumatic distress following deployment.

Abstract:
Military personnel exposed to combat are at risk for experiencing post-traumatic distress that can progress over time following deployment. We hypothesized that progression of post-traumatic distress may be related to enhanced susceptibility to post-deployment stressors. This study aimed at examining the concept of stress sensitization prospectively in a sample of Dutch military personnel deployed in support of the conflicts in Afghanistan.
In a cohort of soldiers (N = 814), symptoms of post-traumatic stress disorder (PTSD) were assessed before deployment as well as 2, 7, 14, and 26 months (N = 433; 53 %) after their return. Data were analyzed using latent growth modeling. Using multiple group analysis, we examined whether high combat stress exposure during deployment moderated the relation between post-deployment stressors and linear change in post-traumatic distress after deployment.
A higher baseline level of post-traumatic distress was associated with more early life stressors (standardized regression coefficient = 0.30, p < 0.001). In addition, a stronger increase in posttraumatic distress during deployment was associated with more deployment stressors (standardized coefficient = 0.21, p < 0.001). A steeper linear increase in posttraumatic distress post-deployment (from 2 to 26 months) was predicted by more post-deployment stressors (standardized coefficient = 0.29, p < 0.001) in high combat stress exposed soldiers, but not in a less combat stress exposed group. The group difference in the predictive effect of post-deployment stressors on progression of post-traumatic distress was significant (χ²(1) = 7.85, p = 0.005).
Progression of post-traumatic distress following combat exposure may be related to sensitization to the effects of post-deployment stressors during the first year following return from deployment.