正念发源于东方佛教的冥想传统，经过西方科学界去宗教化后被广泛用于缓解人的精神痛苦及提升人的幸福感。以往大量的研究发现正念干预可以有效改善不同人群的焦虑和抑郁，以及在日常生活中更具正念倾向的个体更少体验到焦虑和抑郁。尽管正念对焦虑抑郁的改善效果已经得到了大量实证研究的支持，正念缓解焦虑抑郁的作用机制尚不明确。本论文通过一个横断研究和一个随机对照的干预研究来检验焦虑敏感性是否为正念缓解焦虑抑郁的机制。

研究1分别用五因素正念量表、焦虑敏感指数量表3版以及抑郁-焦虑-压力量表来测量特质正念、焦虑敏感性以及焦虑抑郁。通过网络问卷平台收集到409份普通成年人被试的有效问卷。相关分析结果表明，特质正念与焦虑抑郁以及焦虑敏感性均显著负相关，而焦虑敏感性则与焦虑抑郁显著正相关；最重要的是，焦虑敏感性显著中介了特质正念与焦虑抑郁之间的关系，这说明焦虑敏感性为正念缓解焦虑抑郁的潜在机制。

研究2在研究1的基础上，通过实验性的随机对照干预研究，检验焦虑敏感性是否为旨在培育特质正念的8周正念干预缓解焦虑抑郁的机制。研究2招募了69名高心理困扰的被试，将他们随机分配到正念干预组（35人）和等待对照组（34人）。正念干预组的被试参加为期8周的正念干预；等待对照组的被试则在8周干预组接受正念训练期间不接受任何干预。研究2使用总体焦虑水平及干扰程度量表、总体抑郁水平及干扰程度量表以及焦虑敏感指数量表3版分别测量焦虑、抑郁以及焦虑敏感性。两组被试分别在正念干预开始前一周时间内和结束后的一周时间内填写这些量表。结果发现，相比于等待对照组，8周正念干预显著降低了被试的焦虑、抑郁和焦虑敏感性。最重要的是，焦虑敏感性的前后测变化分别在组别（干预组vs.等待对照组）与焦虑、抑郁的前后测变化的关系中起着中介作用。说明焦虑敏感性为正念缓解焦虑抑郁的作用机制。

研究2与研究1结合在一起，强有力地说明了焦虑敏感性在正念缓解焦虑抑郁过程中发挥的机制作用。本论文的发现在科学研究层面上能为理解正念缓解焦虑抑郁的原因提供新的视角，在实践层面上则能为进一步最大化正念干预对焦虑抑郁的效果，以及在复杂的现实情境中保持正念干预的疗效提供思路。

Mindfulness, originating in the Eastern Buddhist meditation tradition, has been secularized by Western scientists to alleviate mental suffering and enhance well-being. Many studies have found that anxiety and depression in different populations could be improved by mindfulness-based interventions and that individuals who are more mindful in their daily lives experience less anxiety and depression. Although the efficacy of mindfulness on anxiety and depression have been supported by a large body of empirical studies, the mechanisms by which mindfulness works to alleviate anxiety and depression are unclear. Through a cross-sectional study and a randomized controlled intervention study, this thesis examined whether anxiety sensitivity was the mechanism by which mindfulness could relieve anxiety and depression.

In Study 1, the Five Facet Mindfulness Questionnaire, the Anxiety Sensitivity Index-3, and the Depression Anxiety Stress Scale-21 were used to measure trait mindfulness, anxiety sensitivity, anxiety and depression, respectively. A total of 409 valid questionnaires were collected from general adults through an online questionnaire platform. It was found that trait mindfulness had significant and negative correlations with anxiety and depressive symptoms and anxiety sensitivity, while anxiety sensitivity had significant and positive correlations with anxiety and depressive symptoms. Most importantly, anxiety sensitivity significantly mediated the relationship between trait mindfulness and anxiety and depressive symptoms, suggesting that anxiety sensitivity is a potential mechanism for mindfulness to alleviate anxiety and depression.

Based on the findings of Study 1, Study 2 tested whether anxiety sensitivity was the mechanism by which an 8-week mindfulness-based intervention designed to cultivate trait mindfulness alleviated anxiety and depression in a randomized controlled trial. Sixty-nine participants with high psychological distress were randomly assigned to a mindfulness-based intervention group (35 participants) or a waitlist control group (34 participants). Participants in the intervention group participated in an 8-week mindfulness-based intervention program. And participants in the waitlist control group did not receive any intervention when participants in the intervention group underwent mindfulness training. In this study, anxiety, depression, and anxiety sensitivity were measured using the Overall Anxiety Severity and Impairment Scale, the Overall Depression Severity and Impairment Scale, and the Anxiety Sensitivity Index-3, respectively. Participants in both groups completed these questionnaires within one week prior to the start of the mindfulness-based intervention and within one week after the end of the intervention, respectively. Results showed that the 8-week mindfulness-based intervention significantly reduced anxiety, depression, and anxiety sensitivity compared to the waitlist control group. Most importantly, changes in anxiety sensitivity from pre- to post-test mediated the relationships between group (intervention group vs. waiting control group) and changes in anxiety and depression from pre- to post-test, respectively. This suggests that anxiety sensitivity is the mechanism for mindfulness to alleviate anxiety and depression.

Combining Study 2 with Study 1, the thesis strongly illustrated the mechanistic role that anxiety sensitivity played in the alleviation of anxiety and depression by mindfulness. In terms of scientific research, the findings of this thesis offer a new perspective for understanding why mindfulness can alleviate anxiety and depression. Regarding practice, the findings of this thesis can provide ideas for further maximizing the effects of mindfulness-based interventions on anxiety and depression and maintaining the efficacy of mindfulness-based interventions in complex real-life contexts.