KMAN Publication Inc. (KMANPUB) Journal of Adolescent and Youth Psychological Studies (JAYPS) 2981-2526 6 Serial Number 37 2025 09 10 The Effectiveness of Acceptance and Commitment Therapy on Obsessive Beliefs in University Students The Effectiveness of Acceptance and Commitment Therapy on Obsessive Beliefs in University Students 1 9 10.61838/kman.jayps.4364 EN Journal Article 2025 04 05 <table> <tbody> <tr> <td> <p><strong>Objective:</strong>  The present study aimed to examine the effectiveness of Acceptance and Commitment Therapy (ACT) on obsessive beliefs and their components in university students.</p> <p><strong>Methods and Materials: </strong>This applied, quantitative research employed a quasi-experimental pretest–posttest design with a control group and a two-month follow-up. The statistical population comprised all undergraduate law students admitted in 2024 at the Islamic Azad University, Shiraz Branch. Using convenience sampling, 78 students were selected and randomly assigned to an experimental group (n = 39) receiving ACT and a control group (n = 39) receiving no intervention. The Obsessive Beliefs Questionnaire-44 (OBQ-44) was administered at pretest, posttest, and follow-up. The ACT intervention followed Steven C. Hayes’s eight-session, 90-minute protocol. Data were analyzed using univariate and multivariate analyses of covariance (ANCOVA, MANCOVA) in SPSS version 26 after confirming the relevant parametric assumptions.</p> <p><strong>Findings: </strong>ANCOVA results indicated significant differences between the experimental and control groups at posttest in all obsessive belief components—general beliefs (p = 0.006, η² = 0.115), perfectionism and certainty (p &lt; 0.001, η² = 0.422), responsibility (p = 0.021, η² = 0.082), thought control (p = 0.020, η² = 0.083), and complete performance (p &lt; 0.001, η² = 0.414)—as well as in the total obsessive beliefs score (p &lt; 0.001, η² = 0.480). Adjusted posttest means showed lower scores in the experimental group compared to the control group across all measures. Follow-up analysis confirmed the maintenance of treatment effects over two months.</p> </td> </tr> </tbody> </table> <p><strong>Conclusion: </strong>Acceptance and Commitment Therapy significantly reduced obsessive beliefs and their subcomponents in university students, with effects maintained at follow-up. The findings highlight ACT’s potential as an effective cognitive-behavioral intervention for addressing maladaptive belief patterns in student populations.</p> https://journals.kmanpub.com/index.php/jayps/article/download/4364/7697