Dr. Arthur R. Rademaker
Samenvatting van het proefschrift
The goal of this dissertation is to increase understanding of individual differences in vulnerability for and resilience to trauma in military personnel. Specifically, the studies in this dissertation examined clinical symptoms and personality profiles of Dutch peacekeepers and sought to elucidate how personality may moderate risk and resilience to posttraumatic stress disorder (PTSD) in soldiers and veterans. Personality affects the development of trauma-related psychopathology at different stages. It may play a role in the development of PTSD by affecting the risk of exposure to trauma and / or by influencing the individual’s potential to effectively deal with stress and trauma. Although the cross-sectional studies in this dissertation foreclose inferences on causality, we demonstrated that healthy soldiers who report more childhood trauma display personality traits that were previously associated with interpersonal problems and mental disorders. Furthermore, the data demonstrated that personality may affect coping resources and behaviour. Hardiness facilitates coping by increasing social support and the use of problem oriented coping behaviour whereas increased neuroticism has opposite effects. Personality may also affect the course of PTSD: personality traits neuroticism and optimism are directly related (in opposite directions) to concurrent symptom severity. Personality vulnerability and resilience factors are closely related. The absence of the former can imply the presence of the latter. However, in some instances it is difficult to disentangle risks from resilience. This dissertation demonstrated that the personality trait of neuroticism is closely (inversely) related to optimism and hardiness, and that both adaptive and maladaptive personality traits can be related to similar underlying biological systems. That is, both harm avoidance and self-directedness are related to hypothalamic-pituitary-adrenal (HPA) axis functioning as measured by the increase in salivary cortisol after awakening. Finally, the need for effective prevention and treatment programs for stress-related disorders in peacekeeping veterans is illustrated by two studies that showed that Dutch veterans with (chronic) PTSD symptoms report diffuse psychiatric symptoms and personality problems, not too dissimilar from what was previously observed in Vietnam veterans, and that their symptoms are difficult to treat. In conclusion, this dissertation demonstrates that personality is an important determinant of post-traumatic morbidity and functioning. Therefore, personality assessment can aid in improving screening programs and may prove useful to optimize military training and treatment programs. However, a number of issues need to be resolved before personality psychology can fulfil its full potential. These include addressing the need for more sophisticated and ‘fine-grained’ assessment procedures on the one hand, and providing more insight into the dynamic relationship between trauma and personality on the other.