The effects of stress on involuntary memories

Background of the study:

To improve prevention of posttraumatic stress disorder, it is important to increase our understanding of the biological and cognitive mechanisms underlying the development of its hallmark symptom, i.e. intrusive memories. Individual variation in endocrine stress reactivity to the traumatic event, resulting in decreased contextual memory processing, is thought to underlie intrusive memory development. Studying these process in more detail is only feasible in healthy individuals using an experimental trauma paradigm. However, the best currently available paradigm, the trauma film paradigm (consisting of watching a film with aversive graphic footage of traumatic events) does not result in consistent activation of the two most important stress systems, i.e. the autonomic nervous system and hypothalamic-pituitaryadrenal axis, limiting ecological validity of this paradigm and therefore hampering reliable investigations into intrusive memory development. Therefore, the aim of this study is to adapt this trauma film paradigm, which is expected to result in more robust endocrine stress responses and increased frequency of intrusive memories.



Objective of the study:

The primary objective is to investigate whether adding a brief mild psychosocial stressor (socially-evaluated cold pressor test) immediately prior to an experimental analogue traumatic event (trauma film paradigm) increases acute endocrine stress reactivity (salivary cortisol and alpha amylase output) throughout the experimental paradigm and increases intrusion frequency in the following week.

Secondary, it will be investigated whether addition of a stressor affects voluntary memory accuracy and intrusion characteristics related to the trauma film. Furthermore, the impact of
individual variation in endocrine stress reactivity throughout the paradigm and glucocorticoid receptor functioning on voluntary and intrusive memories related to the trauma film will be investigated.

Primary: Adding a brief mild psychosocial stressor immediately prior to an experimental analogue traumatic event (the frequently used and well-validated trauma film paradigm) will increase the ecological validity of the analogue traumatic event, by increasing the acute stress reactivity and intrusion frequency in the following week.

T0: screening

T1: baseline session

T2: experimental session

T2.1-2.17: 7 day intrusion monitoring

T3: one-week follow-up session

Socially-evaluated cold pressor task versus warm water control condition without social evaluation. Additionally, all participants will watch a trauma film, known to induce intrusive memories in the
following week.