KMAN Publication Inc. Quality of Life and Health Sciences 1 Serial Number 2 2025 10 01 The Effectiveness of Acceptance and Commitment Therapy on Psychological Flexibility, Pain Catastrophizing, and Quality of Life Among Adults With Chronic Pain The Effectiveness of Acceptance and Commitment Therapy on Psychological Flexibility, Pain Catastrophizing, and Quality of Life Among Adults With Chronic Pain 1 13 10.61838/a51aa064 EN Journal Article 2025 04 13 <table> <tbody> <tr> <td> <p><strong>Objective:</strong>  This study aimed to determine the effectiveness of Acceptance and Commitment Therapy on psychological flexibility, pain catastrophizing, and quality of life among adults with chronic pain.</p> <p><strong>Methods and Materials: </strong>This quasi-experimental study was conducted using a pretest–posttest design with a control group and a two-month follow-up. The statistical population included adults with chronic pain who referred to pain clinics, rehabilitation centers, and specialized medical centers in Isfahan, Iran. A total of 50 eligible participants were selected through purposive sampling and assigned to an experimental group and a control group, with 25 participants in each group. The experimental group received Acceptance and Commitment Therapy in eight weekly 90-minute sessions, while the control group received routine care and no structured psychological intervention during the same period. Data were collected using the Psychological Inflexibility in Pain Scale, the Pain Catastrophizing Scale, and the 36-Item Short Form Health Survey. Data were analyzed using repeated-measures analysis of variance and Bonferroni post hoc comparisons.</p> <p><strong>Findings: </strong>The results showed a significant main effect of time for pain-related psychological inflexibility, pain catastrophizing, and quality of life (p &lt; .001). The main effect of group was also significant for all three variables (p &lt; .001). Most importantly, the time-by-group interaction was significant for pain-related psychological inflexibility (F = 44.93, p &lt; .001, η² = .484), pain catastrophizing (F = 39.84, p &lt; .001, η² = .454), and quality of life (F = 47.28, p &lt; .001, η² = .496). Bonferroni comparisons indicated significant improvements from pretest to posttest and from pretest to follow-up in the experimental group (p &lt; .001), while posttest-to-follow-up differences were not significant.</p> <p><strong>Conclusion: </strong>Acceptance and Commitment Therapy was effective in improving psychological flexibility, reducing pain catastrophizing, and enhancing quality of life among adults with chronic pain, and these effects remained stable at the two-month follow-up.</p> </td> </tr> </tbody> </table> https://journals.kmanpub.com/index.php/qlhs/article/download/5778/10943