A coach-guided Acceptance and Commitment Therapy (ACT) intervention that uses a blended approach of two face-to-face and five online sessions (iACT; N = 33) has been found to be more effective than a waiting-list control condition (WLC; N = 35) at enhancing the wellbeing of university students while also reducing stress and depression. The present study explored possible mediators of change that may account for the outcomes of the study. Mediation analyses revealed that changes in the non-reactivity subscale of mindfulness mediated changes in wellbeing, depression, and stress in the iACT group. In addition, changes in the sense of coherence subscale of meaningfulness mediated changes in all outcomes. Psychological flexibility and cognitive defusion did not mediate changes in outcomes. The results suggest that the use of practices focusing on non-reactivity, meaning the ability to allow thoughts and feelings to come and go without getting carried away by them, is especially important for enhancing the wellbeing of university students. A focus on enhancing meaningfulness also plays a significant role in reducing psychological distress. These findings provide a first step toward understanding the potential mechanisms of change taking place in brief, Internet-supported, blended ACT programs.

教练指导的接受与承诺疗法 (ACT) 干预采用两次面对面和五次在线课程的混合方法 (iACT； N = 33)，已被发现比等待名单控制条件更有效（ WLC； N = 35) 提高大学生的福祉，同时减少压力和抑郁。本研究探讨了可能解释研究结果的可能的变化中介因素。中介分析显示，正念非反应分量表的变化介导了 iACT 组的幸福感、抑郁和压力的变化。此外，意义的连贯性分量表的变化介导了所有结果的变化。心理灵活性和认知解离并没有调节结果的变化。结果表明，使用注重非反应性的实践，即允许思想和感情来来去去而不被其带走的能力，对于提高大学生的幸福感尤其重要。注重增强意义在减少心理困扰方面也发挥着重要作用。这些发现为理解简短的、互联网支持的混合 ACT 项目中发生的潜在变革机制迈出了第一步。