Cognitive flexibility is critical for psychiatric nurses facing high-stress environments, yet effective interventions to enhance this skill are underexplored. This quasi-experimental study aimed to evaluate the impact of Acceptance and Commitment Therapy (ACT) on cognitive flexibility among psychiatric nurses. Sixty-two nurses from Razi and Saraye Ehsan psychiatric centers in Tehran were randomly assigned to experimental and control groups (n = 31 each). The experimental group participated in eight 90-minute group-based ACT sessions, adapted from Mohagheghi et al. (2015), incorporating interactive exercises, mindfulness practices, and homework to foster psychological flexibility. The control group received no intervention. Cognitive flexibility was assessed using the Cognitive Flexibility Inventory (CFI) at pretest and post test. Paired t-tests and analysis of covariance (ANCOVA) were employed to analyze within-group and between-group differences, controlling for pretest scores. The experimental group showed a significant increase in CFI scores (M_diff = 17.14, SD = 5.27; t(30) = 18.12, p < .001). ANCOVA revealed a significant group effect (F(1, 60) = 19.63, p < .001, η² = 0.71), with 71% of post test score variance attributed to the intervention. No significant demographic differences were found between groups. The findings suggest that ACT is an effective intervention for enhancing cognitive flexibility among psychiatric nurses, potentially improving their ability to cope with workplace stress. However, the small sample size and lack of long-term follow-up limit generalizability. Future research should explore ACT’s sustained effects and applicability across diverse healthcare settings.
