Objective: To review the impact of mindfulness-based stress reduction (MBSR) on symptoms of anxiety and depression in a range of clinical populations.
Method: Our review included any study that was published in a peer-reviewed journal, used a control group, and reported outcomes related to changes in depression and anxiety. We extracted the following key variables from each of the 15 studies identified: anxiety or depression outcomes after the MBSR program, measurement of compliance with MBSR instructions, type of control group included, type of clinical population studied, and length of follow-up. We also summarized modifications to the MBSR program.
Results: Measures of depression and anxiety were included as outcome variables for a broad range of medical and emotional disorders. Evidence for a beneficial effect of MBSR on depression and anxiety was equivocal. When active control groups were used, MBSR did not show an effect on depression and anxiety. Adherence to the MBSR program was infrequently assessed. Where it was assessed, the relation between practising mindfulness and changes in depression and anxiety was equivocal.
Conclusions: MBSR does not have a reliable effect on depression and anxiety.
(Can J Psychiatry 2007;52:260-266)
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* MBSR is increasingly being used to improve medical and emotional symptoms in a wide range of clinical populations.
* Depression and anxiety are almost always measured in such research and may be the mechanism by which improvement in quality of life and improved functioning occur.
* Evaluating the effect of MBSR on depression and anxiety is important to evaluate the effectiveness of this emerging modality.
* Methodological variability in the studies reviewed precludes strong conclusions.
* The paucity of randomized clinical trials with active control groups limits the support for the unique efficacy of MBSR when changes in depression and anxiety symptoms are found.
* Depression and anxiety do not reliably improve after patient participation in MBSR.
Key Words: mindfulness-based stress reduction, depression, anxiety, review, therapy
Abbreviations used in this article
BDI Beck Depression Inventory
DAS Dysfunctional Attitudes Scale
MBSR mindfulness-based stress reduction
POMS Profile of Mood States
SCL-90 Symptom Check List-90
STAI State-Trait Anxiety Inventory
Mood and anxiety disorders are among the most common psychiatric disorders in Canada and are frequently comorbid with other mental and medical disorders.1'2 Despite the growing availability of effective pharmacotherapies and psychotherapies specific to anxiety and depressive disorders,3,4 innovative conceptual and therapeutic models of care continue to emerge that may be relevant to the amelioration of anxiety and depression in a broad range of medical and emotional disorders. MBSR, in particular, has emerged as one of the better-known clinical applications of mindfulness meditation,5,6 that has been shown to significantly benefit individuals with a diverse set of medical and psychiatric conditions, including chronic pain,5 cancer,7 anxiety disorders,8 depression,9 eating disorders,10 and fibromyalgia.11 (Kabat-Zinn defines mindfulness as the "awareness that emerges through paying attention on purpose, in the present moment, and nonjudgmentally to the unfolding of experience moment by moment."12, p 145) The reduction of depression and anxiety symptoms after MBSR may be a primary pathway by which an individual experiences enhanced mental and physical health (for example, through less pain, reduced disability, or greater hope and confidence) and thus may be an important indicator of the efficacy of MBSR, given the often chronic and recurrent nature of many of the medical conditions (such as cancer) with which MBSR participants present. …