CRD summary

This review investigated whether exercise interventions are an effective treatment for depression. The authors concluded that exercise can be a powerful intervention for clinical depression. The reliability and generalisability of the conclusion was unclear as the quality of the evidence was not assessed and the statistical and clinical diversity of the studies were not considered.

Authors' objectives

To examine the efficacy of exercise treatments for depression and other affective mental disorders.

Searching

PsycINFO, MEDLINE and the Cochrane CENTRAL Register were searched up to 2005 for English language studies published in peer-reviewed journals; the search terms were provided. The references of review articles were also checked.

Study selection

Assessment of study quality

The authors did not state that they assessed validity.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

Hedge's g was used to calculate the effect size and 95% confidence interval (CI) for each study and a correction was made for small sample size. Where the standard deviation was not reported, g was estimated using the t or F statistic where available.

Methods of synthesis

Results of the review

Eleven RCTs (n=513) were included.

Depression scores were lower with an exercise intervention compared with control (effect size 1.39, 95% CI: 0.89, 1.88). More recently published studies were associated with a larger effect size. The authors concluded that, in terms of risk of publication bias, the overall effect size was robust as 367 current or future studies with an effect size of zero would be required to change the findings to one of no difference between the exercise and control groups.

Authors' conclusions

The meta-analysis of studies of individuals with depression yielded a very large effect size, showing that exercise can be a powerful intervention for clinical depression.

CRD commentary

The authors stated a reasonably clear review question although the severity of depression that was considered relevant was unclear. Some relevant sources were searched, but some studies might have been missed due to the exclusion of unpublished and non-English language studies. However, the authors did explore the potential impact of publication bias and assessed the risk as low. It is unclear what methods, if any, were used to reduce error and bias in the review processes and the quality of the included studies was not assessed. Statistical heterogeneity was not assessed, therefore it is unclear whether it was appropriate to pool the studies in a quantitative synthesis. The included studies appeared diverse in terms of the intervention, comparator and participants and the effect size varied considerably between studies; the overall effect size may therefore have limited generalisability and may not be reliable.

Implications of the review for practice and research

Practice: The authors stated that clinicians should consider adding exercise interventions to their treatment strategies for patients with depression.

Research: The authors did not state any implications for further research.

Bibliographic details

Stathopoulou G, Powers M B, Berry A C, Smits J A, Otto M W. Exercise interventions for mental health: a quantitative and qualitative review. Clinical Psychology: Science and Practice 2006; 13(2): 179-193.

Indexing Status

Subject indexing assigned by CRD

MeSH

Anorexia Nervosa /psychology; Anxiety /therapy; Behavior Therapy /methods; Body Image; Bulimia /psychology; Depression /prevention & control; Exercise /physiology /psychology; Exercise Therapy; Feeding Behavior; Health Behavior; Mental Health; Motivation; Self Concept

AccessionNumber

12006002281

Database entry date

31/05/2007

Record Status

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.