The effectiveness of exercise as an intervention in the management of depression: systematic review and meta-regression analysis of randomised controlled trials

doi:10.1136/bmj.322.7289.763

BMJ 2001;322:763 ( 31 March )

Papers

The effectiveness of exercise as an intervention in the management of depression: systematic review and meta-regression analysis of randomised controlled trials

Debbie A Lawlor, lecturer in epidemiology and public health medicine, ^a Stephen W Hopker, consultant psychiatrist. ^b

^a Department of Social Medicine, University of Bristol, Bristol BS8 2PR, ^b Bradford Community Trust, Shipley, West Yorkshire BD18 3BP

Correspondence to: D A Lawlor D.A.Lawlor{at}bristol.ac.uk

Objective: To determine the effectiveness of exerciseas an intervention in the management ofdepression.
Design: Systematic review and meta-regression analysisof randomised controlled trials obtained from five electronicdatabases (Medline, Embase, Sports Discus, PsycLIT, Cochrane Library)and through contact with experts in the field, bibliographic searches,and hand searches of recent copies of relevantjournals.
Main outcome measures: Standardised mean difference in effect sizeand weighted mean difference in Beck depression inventory scorebetween exercise and no treatment and between exercise and cognitivetherapy.
Results: All of the 14 studies analysed had importantmethodological weaknesses; randomisation was adequately concealedin only three studies, intention to treat analysis was undertakenin only two, and assessment of outcome was blinded in only one.The participants in most studies were community volunteers, anddiagnosis was determined by their score on the Beck depressioninventory. When compared with no treatment, exercise reduced symptomsof depression (standardised mean difference in effect size -1.1(95% confidence interval -1.5 to -0.6); weighted mean differencein Beck depression inventory -7.3 (-10.0 to -4.6)). The effectsize was significantly greater in those trials with shorter followup and in two trials reported only as conference abstracts. Theeffect of exercise was similar to that of cognitive therapy (standardisedmean difference -0.3 (95% confidence interval -0.7 to 0.1)).
Conclusions: The effectiveness of exercise in reducingsymptoms of depression cannot be determined because of a lackof good quality research on clinical populations with adequatefollowup.

What is already known on this topic
Depression is common

Management is often inadequate and many patients do not comply with antidepressant medication

The effect of exercise on depression has been a subject of interest for many years

What this study adds
Most studies of the effect of exercise on depression are of poor quality, have brief follow up, and are undertaken on non-clinical volunteers

Exercise may be efficacious in reducing symptoms of depression in the short term but its effectiveness in clinical populations is unknown

A well designed, randomised controlled trial with long term follow up is needed

© BMJ 2001