Post-event rumination and impaired cortisol recovery following social-evaluative stressors in social anxiety

Abstract

Background: Individuals with social anxiety show impaired cortisol recovery following social-evaluative stressors; however, the mechanism underlying such impaired recovery remains unclear. This study examined the effect of post-event rumination (PER)—repetitive thinking about past social situations—on cortisol recovery. Methods: Forty-two university students (23 women, mean age = 22.0 ± 2.0 years) completed the Social Phobia Scale, the Social Interaction Anxiety Scale, and the Trier Social Stress Test (TSST), followed by thought sampling procedure that assessed their PER about experiences during TSST. Saliva sampling was conducted twice before TSST and six times after TSST, every 10 min. We examined whether social anxiety and PER predict cortisol recovery using linear growth models. To avoid biases in estimation, we analysed responders (>20% cortisol rise from baseline; n = 22) and non-responders (n = 20) in separate models, based on previous studies. Findings: Among responders, PER predicted lower recovery rates (t = 2.33, p < .05), and the effect was prominent at low levels of social anxiety (Z = 3.12, p < .01). Among non-responders, no effect of PER was observed, and a linear declining trajectory was observed throughout the experiment (t = 4.10, p < .01). Discussion: These findings suggest that PER causes cortisol recovery impairment both at high and low levels of social anxiety, among those who exhibit cortisol response to social stressors. The linear declining trajectory among non-responders suggests that they responded to a novel experimental situation itself but not to TSST, which explains the lack of effect of PER on non-responders.