Comparison of the Effectiveness of Acceptance and Commitment Therapy and Unified Transdiagnostic Treatment on Cognitive Flexibility in Nurses with Post-Traumatic Stress Symptoms (PTSD) Caused by COVID-19 Infection

This study aimed to compare the effectiveness of Acceptance and Commitment Therapy (ACT) and Unified Transdiagnostic Treatment (UP) on cognitive flexibility in nurses with PTSD symptoms following COVID-19 infection. A quasi-experimental design with pre-test, post-test, and two-month follow-up was used on 30 nurses with PTSD symptoms based on the Keane PTSD questionnaire (cut-off score 107) working at Shahid Seyed Mostafa Khomeini Hospital in Tabas. Participants were randomly assigned to ACT, UP, or control groups (10 per group). The ACT and UP interventions consisted of eight weekly sessions following validated protocols. Cognitive flexibility was assessed using the Dennis and Vander Wal (2010) questionnaire, measuring perceived controllability, perceived justification of behavior, and alternative option generation. PTSD symptoms were measured by the Keane et al. (1988) questionnaire. Data analysis included descriptive statistics, ANCOVA, MANCOVA, and Bonferroni post hoc tests using SPSS-22. Results indicated significant differences among groups in all cognitive flexibility components at post-test and follow-up stages after controlling for pre-test scores (p < .01). The UP group showed significantly higher improvements than the ACT group in perceived controllability and generation of alternative options at both post-test and follow-up (p < .01). ACT also significantly outperformed the control group in all cognitive flexibility components (p < .05). Effect sizes ranged from moderate to large (η² = .32–.55), indicating clinically meaningful differences. Both ACT and UP effectively improved cognitive flexibility among nurses with PTSD symptoms, but UP demonstrated greater efficacy in enhancing perceived controllability and generation of alternative options. These findings support the use of UP as a robust transdiagnostic intervention to improve trauma recovery and adaptive functioning in professionals exposed to high occupational stress.