Effect of cognitive flexibility in mindfulness intervention for emotional distress: Two randomized controlled trials

To examine the mechanistic role of cognitive flexibility in mindfulness intervention for emotional distress (MIED), we conducted two randomized controlled trials. In Study 1, 607 participants experiencing high emotional distress were randomly assigned to either an MIED program group (N = 304) or a waitlist control group (N = 303). Levels of cognitive flexibility, anxiety, depression, and general emotional distress were assessed at baseline (T0), Week 3 (T3), Week 5 (T5), and Week 7 (postintervention, T7). Study 2 included 89 participants with high emotional distress, randomly assigned to either an MIED group (N = 45) or a control group (N = 44). The same measures were assessed weekly, and cognitive flexibility was measured by a behavioral task at T0, T3, T5, and T7. All measures showed significant improvement in the MIED group. The effects of the MIED program on the change in emotional distress at a later time were significantly mediated by the change in cognitive flexibility during the intervention. Hierarchical regression analysis showed that more efficient shifting of attention away from affective toward nonaffective aspects of positive stimuli at T5, and less efficient shifting of attention away from affective aspects of negative stimuli to positive stimuli at T3, predicted greater reductions in emotional distress at T7. The MIED program alleviated emotional distress by enhancing cognitive flexibility, suggesting that cognitive flexibility is a key mechanism underlying the intervention. (PsycInfo Database Record (c) 2025 APA, all rights reserved).