Examining the Effects of Induced Rumination on HPA-Axis Regulation

Rumination impacts a persons' ability to cope with stress and may prolong or intensify the HPA-axis stress response. Prior studies have shown that ruminative tendencies are associated with greater HPA-axis response to laboratory stressors. However, most past studies have been correlational or have manipulated rumination before the stress task, making it difficult to tease apart stress-task induced rumination tendencies from individual differences in trait rumination. Therefore, the current study used an experimental protocol that manipulated rumination after a psychosocial stressor, while simultaneously assessing individual differences in trait rumination. This study examined 70 participants (35 males; age 18-21) who underwent a psychosocial stress task, and the Trier Social Stress Task (TSST). After the TSST, participants were randomly assigned to a rumination task (answering questions designed to elicit rumination about their performance) or a distraction task (completing non-evocative questions about their performance). We also assessed trait rumination prior to the TSST. A total of 10 saliva cortisol samples were obtained throughout the protocol. While salivary cortisol levels did not differ between the rumination or distraction condition, there was an interaction between trait rumination and experimental condition. Higher trait rumination was associated with prolonged duration of HPA-axis activation, but not higher intensity, only in the induced rumination condition. Trait rumination was not associated with HPA response in the distraction condition. Our findings suggest that one's individual tendency to ruminate prolonged the activation of the HPA-axis but this effect is mitigated if a person engages in distraction after a stress task. This suggests that trait aspects interact with contextual aspects (e.g., social context fosters rumination vs. distraction) in shaping HPA-axis reactivity to psychosocial stress. The implications of these findings are discussed.Master of SciencePsychology Accelerated Master's Degree ProgramUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/111892/1/shull.alexa.finalthesis.pd