Anxiety mediates the effect of acute stress on working memory performance when cortisol levels are high: a moderated mediation analysis

Background: Anxiety is an aversive emotional state characterized by perceived uncontrollability and hypervigilance to threat that can frequently cause disruptions in higher-order cognitive processes like working memory. The attentional control theory (ACT) predicts that anxiety negatively affects the working memory system. Design: This study tested the association between anxiety and working memory after the addition of stress and measured the glucocorticoid, cortisol. To better understand this relationship, we utilized a moderated mediation model. Methods: Undergraduate students from a public university (N = 103) self-reported their anxiety levels. Participants first completed a short-term memory test. During and after a forehead cold pressor task (stress vs. control procedure) participants completed a working memory test. Salivary cortisol was taken at baseline and after the last working memory test. Results: Overall, acute stress had no effect on working memory. However, we found that anxiety levels mediated the influence of condition (stressed vs. control) on working memory, but only among those individuals who had high cortisol levels after exposure to acute stress, supporting a moderated mediation model. Conclusions: These results imply that activation of the hypothalamic–pituitary–adrenal axis was necessary for working memory impairment in anxious individuals. These results provide support for the ACT.