The Effectiveness of Mindfulness-Based Interventions on Anxiety Disorders. A Systematic Meta-Review

There has been a growing interest in the study of the effectiveness of mindfulness-based interventions (MBIs). Many clinical trials and experimental designs have been implemented, with different samples and diverse MBI procedures. Reviews have shown unclear results, apart from a tendency to identify low-to-moderate effectiveness. The purpose of this review is to examine the effectiveness of MBIs on anxiety complaints, analyzing available systematic reviews and meta-analyses. The literature search was done in MEDLINE (PubMed) and PsycINFO, from the first available review in 2003 until March 2020. From 82 initial references, 12 reviews were selected. Reviews confirmed a moderate effect size of MBIs in improving anxiety symptoms. This efficacy was similar to that of well-established therapies for reducing anxiety symptoms, such as cognitive behavioral therapies. A large effect size was found when well-developed MBI protocols were applied. More refined clinical trials are needed to establish clear conditions of MBI effectiveness (protocols, samples, psychological mechanisms, etc.). In addition, considering mindfulness processes, new outcome measures are needed (such as acceptance, self-awareness, or well-being) to test the incremental value of MBIs.