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PAPERS: Debbie A Lawlor and Stephen W Hopker The effectiveness of exercise as an intervention in the management of depression: systematic review and meta-regression analysis of randomised controlled trials BMJ 2001; 322: 763 [Abstract] [Full text]

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Exercise and depression

Stuart Biddle   (2 April 2001)

Author's Reply

Debbie A Lawlor   (10 April 2001)

Exercise and depression 2 April 2001
Stuart Biddle, Professor of Exercise & Sport Psychology Loughborough University Send response to journal: Re: Exercise and depression	Lawlor and Hopker's meta-regression of exercise and depression may well reflect the BMJ headline 'Effectiveness of exercise in managing depression is not shown by meta-analysis'. However, one should note that even though the research designs included in the analysis were weak, the effect sizes were large. In addition, in a recent review of this field [Mutrie, in Biddle et al. (Eds)(2000). Physical activity and psychological well-being. London: Routledge], it was concluded that exercise may well have a CAUSAL link to reduced depression in clinical groups. Mutrie used criteria established in epidemiological research, thus included data from trials, meta-analyses, large population surveys etc. Don't write off exercise yet!
Author's Reply 10 April 2001
Debbie A Lawlor, Lecturer in Epidemiology and Public Health Medicine Department of Social Medicine, University of Bristol Send response to journal: Re: Author's Reply	Professor Biddle points out 'that even though the research designs included in the analysis were weak, the effect sizes were large.' This statement is consistent with our conclusion that there is no evidence of exercise being clinically effective as a treatment for depression. The characteristics of the trials that identify them as being of poor quality - lack of concealment, analysis that did not use intention to treat and lack of blinding - have each been shown to exaggerate results by 20- 40%[1]. 'Established criteria in epidemiological research' are appropriate for investigating aetiological pathways but this is not the way to investigate clinical effectiveness. Our meta-analysis clearly shows that there is currently no evidence to support exercise as a clinically effective intervention for depression. This is not the same as evidence of no effect. Though difficult, it would not be impossible to design an appropriate high quality randomised controlled trial of clinically diagnosed depressed patients. The outcome should be a dichotomous clinical diagnosis, assessed by someone blind to treatment allocation, and follow- up of at least 12 months should be undertaken. A third arm in the trial of 'social contact' and a qualitative element would also be valuable in trying to determine whether any effect that might be shown was due to the exercise per se or social contact. 1. Schulz KF, Chalmers I, Hayes RJ, Altman DG. Empirical Evidence of Bias. Dimensions of Methodological Quality Associated with Estimates of Treatment Effects in Controlled Trials. JAMA 95;273:408-412.