Abstract
BACKGROUND: Personality traits, such as the character traits self-directedness and cooperativeness, might play a role in the risk of developing post-traumatic stress disorder (PTSD) after deployment to a combat zone. However, it is unclear whether these traits are preexisting risk factors or if event-related changes might also be associated with PTSD symptoms over time. Therefore, the current aim was to assess if military deployment is associated with changes in cooperativeness and self-directedness and to study how these traits are related to PTSD symptom trajectories. METHODS: In a large cohort of military personnel (N = 1007), measurements were performed before, at one and six months, and two and five years after deployment to Afghanistan. Linear mixed-effect models were used to assess the individual change in the traits over time and to study the relation with potential predictors. RESULTS: Cooperativeness was found to remain stable, whereas self-directedness was found to slightly decrease over time. This decrease was related to the development of PTSD symptoms over time. Furthermore, lower levels of self-directedness were associated with the symptomatic trajectories of PTSD symptoms. Lower levels of cooperativeness were only associated with the recovered PTSD trajectory. CONCLUSIONS: So, not only do the findings confirm that lower levels of these character traits are associated with the development of PTSD symptoms, it was also shown that there are differences in the relation between these traits and the course of PTSD symptoms. Studying methods to promote the levels of these character traits might help to improve the resiliency of military personnel.