This well-conducted review assessed the effectiveness of yoga for the treatment of depression. The authors concluded that there are potentially beneficial effects of yoga interventions, but the findings must be interpreted with caution given the variation in interventions, severity of depression and reporting of trial methodology. This is an appropriate conclusion given the limited evidence available.

To assess the effectiveness of yoga for the treatment of depression.

CINAHL, the Cochrane CENTRAL Register, the Cochrane Database of Systematic Reviews, DARE, EMBASE, IndMED, MEDLINE, PsycINFO, AMED, CISCOM and the Cochrane Depression, Anxiety and Neurosis Group's Specialised Register were searched from inception up to at least January 2004; the search terms were reported. The National Research Register and ClinicalTrials.gov were searched for ongoing and unpublished research. The websites of some yoga and mental health organisations were also searched, and the reference lists of relevant reviews were checked. Studies in all languages were eligible.

Study designs of evaluations included in the review

Randomised controlled trials (RCTs) were eligible for inclusion.

Specific interventions included in the review

Studies of yoga or yoga-based exercises were eligible for inclusion. Studies of complex or multiple interventions, or those based solely on meditation, were excluded. The included studies used different forms of yoga though rhythmic breathing was an important component in most of the trials. The duration of the intervention ranged from 3 days to 5 weeks. The comparators were no active intervention, relaxation, partial yoga, electroconvulsive therapy (ECT) and drug therapy.

Participants included in the review

Studies of participants with depression or a depressive disorder were eligible for inclusion. The level of depression in the included studies ranged from mild to severe. In most of the included studies the participants were younger than 50 years of age.

Outcomes assessed in the review

Studies where the outcome was assessed using a depression rating scale were eligible for inclusion. A range of different measures were used to assess symptoms in the included studies; the Beck Depression Inventory was common to three studies.

How were decisions on the relevance of primary studies made?

The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.

The following criteria were assessed: randomisation method, concealment of allocation, blinding, baseline comparison of characteristics, method of dealing with missing values, loss to follow-up or withdrawals, measures of compliance and outcome measures reported. Two reviewers independently assessed study validity. Any disagreements were resolved by discussion or through consultation with a third reviewer.

Two reviewers independently extracted the data. Any disagreements were resolved by discussion or through consultation with a third reviewer.

How were the studies combined?

A narrative synthesis was conducted.

How were differences between studies investigated?

Differences between the studies were discussed in the text and reported in tables.

Five RCTs (n=183) were included.

The methods of randomisation in the included studies were unclear and only one study reported blinding of the assessors. In one study it was reported that Broota relaxation was more effective than the control intervention and progressive relaxation. Shavasana (one study) and Iyengar Yoga (one study) were more effective than no intervention. In one study full Sudarshan Kriya Yoga (SKY) was more effective than partial SKY, but it was less effective than ECT and similar to drug therapy in another study. No adverse effects, other than breathlessness and fatigue (one study), were reported.

There is evidence of potentially beneficial effects of yoga interventions on depressive disorders. However, the findings must be interpreted with caution given the variation in interventions, severity of depression and reporting of trial methodology.

The review question was clearly stated. Several appropriate sources were searched for studies, and attempts were made to reduce the risk of language and publication bias. Appropriate methods were used to reduce the risk of error and bias in the quality assessment and data extraction processes, though it was unclear whether similar methods were used at the study selection stage. Relevant details of the included studies were reported, the narrative synthesis was appropriate, and the study findings were considered in the context of study quality. The authors' conclusions are appropriate.

Practice: The authors did not state any implications for practice.

Research: Further research is needed to investigate which of the potential yoga-based interventions is most effective and for what severity of depression. Studies comparing the effectiveness of anaerobic exercise such as yoga and aerobic exercise are also required.

Department of Health (the NHS Priorities Project).

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.