Effect of verbal suggestions on the cortisol response to stress

INTERVENTION: For this study, participants will be allocated randomly to one of three conditions (placebo, nocebo, control). Conditions differ only with respect to a verbal suggestion that participants will receive with regard to their expected (psychophysiological) stress response to the Trier Social Stress Test, which all participants will be exposed to after receiving the verbal suggestion. Participants in the placebo condition will be told that, based on questionnaires they filled in before the start of the experiments and baseline physiological measures, they are expected to respond in a beneficial way to the subsequent task, and therefore will experience more positive physiological and affective consequences of being stressed. Participants in the nocebo group are told that, based on questionnaires they filled in before the start of the experiments and baseline physiological measures, they are expected to respond in a detrimental way to the subsequent task, and therefore will experience more negative physiological and affective consequences of being stressed. Participants in the control group will receive no suggestion regarding their stress responsiveness. CONDITION: Cortisol, Stress, Placebo effect ; ; PRIMARY OUTCOME: Salivary cortisol (area under the curve from ground) based on four measurements (baseline, directly after stressor and 15 and 30 minutes after stressor) SECONDARY OUTCOME: Heart rate and resulting heart rate variability ; ; Skin conductance ; ; Cognitive bias for positive and negative emotional words and emotional words overall (Emotional STROOP) after stress ; ; Salivary alpha‐amylase ; ; Positive and negative affect assessed with PANAS ; ; Self‐reported stress assessed with stress‐related items on Visual Analogue Scales (VAS) INCLUSION CRITERIA: Female and male healthy volunteers Between 18 and 35 years of age