Psychobiological consequences of stress in sensitive developmental stages and potential protective factors

The aim of the present dissertation is to contribute to the knowledge of the negative health consequences due to early stress experiences in humans and to investigate potential protective factors beneficial for health.
While a stress response to a threatening situation of limited duration is functional, it can become dysfunctional when stressors are chronic or perceived as uncontrollable. Stress during pregnancy, childhood and adolescence has been associated with the development of physical and mental disorders. However, most studies that investigated the association of adverse childhood experiences (ACE) and stress responses in adulthood were conducted on clinical samples and reported contradictive results regarding the alterations of the stress system. Studies on healthy participants are still scarce, however, a few studies observed blunted endocrine and cardiovascular responses to stress in relation to a history of ACEs.
Therefore, the first study reported in this dissertation aimed to replicate the attenuated endocrine and cardiovascular stress reactivity in healthy, female subjects reporting a history of ACEs and furthermore investigated the impact of duration and age of onset of ACEs. Results confirmed that a history of ACEs was associated with a dampened endocrine and cardiovascular stress response to a mental stress test and that especially long enduring, chronic ACEs seem to have the strongest impact on the attenuated stress reactivity (Article 1).
Article 2 investigated the impact of positive affect on biological outcomes in pregnancy. There is accumulative evidence that positive emotions are related to beneficial physical and psychological health outcomes. Furthermore, it is widely accepted that maternal psychosocial stress is a risk factor for obstetric birth outcomes like shorter length of gestation and preterm delivery. Therefore, in this study conducted on 169 women with singleton pregnancies, the hypothesis if maternal positive affect during pregnancy is associated with beneficial consequences in terms of increased length of gestation and reduced risk of preterm birth was tested. Results showed that higher maternal positive affect and a steeper increase in maternal positive affect over pregnancy were positively associated with length of gestation and reduced risk of preterm delivery. It was argued that positive emotions may exert their beneficial effect by impacting maternal and fetal stress and immune systems.
Article 3 investigated the efficacy of the Montreal Imaging Stress Task (MIST) in healthy female subjects. The MIST is a standardized psychosocial stress test and has not been validated outside the MRT in a healthy female sample so far. Results confirmed that the MIST is a valid instrument for inducing a multidimensional stress response and that it can be classified as being a moderate stress test.