The effect of acceptance and commitment therapy on psychological distress and self-critical rumination in infertile women: a quasi-experimental study

Purpose Infertility is a significant source of psychological distress. This study aims to evaluate the effectiveness of acceptance and commitment therapy (ACT) in reducing psychological distress and self-critical rumination among infertile women. Design/methodology/approach A quasi-experimental design with pre-test/post-test and a control group was used. A convenience sample of 50 infertile women from the Urmia Health Center, Iran, were non-randomly allocated to an ACT group (n = 25) or a control group (n = 25). The experimental group received an eight to ten session ACT program, while the control group received no intervention during the study period. Participants completed the Kessler psychological distress scale and the self-critical rumination scale at pre-test and post-test. Data were analyzed using analysis of covariance to compare post-test scores while controlling for pre-test scores and key demographics. A mediation analysis was also conducted. The trial is registered with the Iranian Registry of Clinical Trials (IRCT; https://irct.behdasht.gov.ir/search/result?query = IRCT20250618066207N1). Findings The results revealed that the ACT group demonstrated statistically significant reductions in both psychological distress [F(1, 44) = 54,177, p-value < 0.001, partial η² = 0.99] and self-critical rumination [F(1, 44) = 15,752, p-value < 0.001, partial η² = 0.99] compared to the control group. The mediation analysis indicated a nonsignificant indirect effect, suggesting that the reduction in psychological distress was not mediated by changes in self-critical rumination (ß = 0.28, 95% CI [−13.71, 14.12]). Originality/value This study provides novel evidence that ACT is a highly effective intervention for alleviating psychological distress in infertile women. A unique and valuable contribution is the finding that while ACT reduces both distress and self-critical rumination, the therapeutic benefits for distress are not mediated by a reduction in rumination. This challenges a potential assumption and directs future research to identify the true active mechanisms of ACT in this population.