Acceptance and mindfulness-based therapies have shown efficacy in the treatment of anxiety and depression. Arguably, acceptance and mindfulness-based therapies target core processes in anxiety and depression by increasing mindful attention, decentering, and acceptance. The present study identified randomized controlled trials of acceptance and mindfulness-based therapies for anxiety and depression. Specifically, we aimed to synthesize the indirect effect of the three putative mediators (i.e., mindful attention, decentering, acceptance) on anxiety and depression.

Electronic searches yielded 4989 unique records, which were screened for eligibility by two independent raters, resulting in the identification of 33 eligible studies (30 independent trials). The overall pooled mediating effect of mindful attention, decentering, and acceptance was small to medium (r = 0.145, p < .001). Type of mediation analysis emerged as the only statistically significant moderator. Specifically, studies using correlation-based mediation approaches showed statistically significant mediating effects, while studies using causal time-lag analyses did not yield statistically significant mediating effects. Mediator specificity could not be established.

In conclusion, putative mediators of acceptance and mindfulness-based therapies mediated treatment effects on anxiety and depression. Limitations in study number, designs, and statistical approaches employed restrict conclusions regarding specificity and causality.

接受和基于正念的疗法已显示出治疗焦虑和抑郁的功效。可以说，接受和基于正念的疗法通过增加正念关注、去中心化和接受来针对焦虑和抑郁的核心过程。本研究确定了针对焦虑和抑郁的接受和正念疗法的随机对照试验。具体而言，我们旨在综合三种假定的中介（即正念关注、去中心化、接受）对焦虑和抑郁的间接影响。

电子搜索产生了 4989 条独特的记录，由两名独立评估者筛选其资格，最终确定了 33 项符合条件的研究（30 项独立试验）。正念关注、去中心化和接受的整体综合中介效应从小到中等 ( r  = 0.145, p  < .001)。中介分析类型成为唯一具有统计学意义的调节因素。具体来说，使用基于相关性的中介方法的研究显示出统计学上显着的中介效应，而使用因果时间滞后分析的研究没有产生统计学上显着的中介效应。无法确定介体特异性。

总之，接受和正念疗法的假定介质介导了对焦虑和抑郁的治疗效果。研究数量、设计和采用的统计方法的限制限制了关于特异性和因果关系的结论。