Re: Facilitated physical activity as a treatment for depressed adults: randomised controlled trial
To The Editor:
We observed with dismay the media coverage of Chalder and colleagues’ paper reporting the lack of efficacy of an intervention to encouragephysical activity in treating depression[1]. The Daily Mail was not alone in reporting that ‘Exercise does little to help the symptoms of depression’. But does the trial, as published, support such a view?
The study has an array of methodological flaws many of which are acknowledged by the authors. However, there are more systemic issues. Firstly, if time-based activity targets ‘seemed unrealistic’, then ‘any increase in physical activity, whatever the intensity’ was encouraged. Current recommendations are that exercise should be at moderate (or greater) intensity[2,3], while no data suggest benefits from unstructured low-level increases in exercise – perhaps the reason why NICE support ‘a structured and supervised exercise programme’[4].Secondly, in evaluating success, the use of an(estimated) 1000 METS per week threshold is both arbitrary (in terms of any impact on depression) and unvalidated in its mode of calculation. Many of the subjects also seemed to be taking significant physical activity prior to inclusion – weakening study power to detect an impact. Finally, activitywas not reliably measured: the questionnaire-based recall of activity used in analysis showed (at best) ‘reasonable’ (the authors’ words) agreement with gold standard accelerometry, and poor agreement for more vigorous activity – that perhaps of greatest benefit.
In terms of conduct, between 1/5 and >1/3 of 361 subjects were missing from follow-up at each time point. Three face-to-face meetings and up to 10 telephone contacts were offered, in the hope that five contacts would be achieved by four months. Fully 44% failed to meet even this target.
Thus, an intervention without strong likelihood of impact was incompletely delivered to a depleted group of subjects, many of whom were already active, while changes in vigorous activity were determined using a methodology the researchers showed to have poor validity. Such factors might explain why the authors could only detect ‘some weak evidence of an increase in physical activity levels’ at 4 months. Indeed, only ten more people were ‘active’ in the intervention limb than the non-intervention (8.1% in real terms).
If the study demonstrated anything at all, it is less that a lack of efficacy of exercise in benefitting depressed patients, than that a specific intervention failed to deliver changes in exercise which might have been beneficial. The authors concur, stating it was possible that ‘the increase in activity was not sufficiently large to lead to a measurable influence’.
Existing data do suggest that exercise benefits depressed patients. As far back as 1905, Franz et al recorded the first case series showing the effect of moderate physical activity on the cognitive, physical and emotional conditions of two patients with severe depression[5]. More recent systematic review of robust trials[6] and meta-analyses[7] are confirmatory. The challenge, then, is how most effectively and cheaply to engage patients in moderate-vigorous exercise. The value of the latest paper is that it shows one process which is ineffective in doing so – not that it demonstrates a lack of efficacy of appropriate exercise in treating depression. ‘NHS Choices’ made this distinction clear, commenting that the study “assessed just one type of exercise intervention [our emphasis].’
Why, then, would the BBC run the headline ‘Exercise no help for depression’? Perhaps the answer lies with the BMJ itself. “This carefully designed research study has shown that exercise does not appear to be effective in treating depression", ran their press release – a message reinforced on the BBC Radio 4’s Today programme (audio available at http://news.bbc.co.uk/today/hi/today/newsid_9726000/9726228.stm), an author stating that exercise ‘is not good for treating people… [with] depression’ and that exercise ‘is not appropriate’ in such circumstances.
We do not believe that the paper, as published, supports such a conclusion.
Yours Sincerely,
Dr Sarah Davies, Sport and Exercise Medicine Trainee (London Deanery).
Dr Jo Larkin, Sport and Exercise Medicine Trainee (London Deanery).
Dr Mike Loosemore, Consultant Sport and Exercise,University College London Hospitals.
Prof Hugh Montgomery, Director, UCL Institute for Human Health and Performance.
References:
1. Chalder et al. Facilitated physical activity as a treatment for depressed adults: randomised controlled trial. BMJ 2012;344:e2758.
2.Department of Health. Bull, FC. et al.Physical Activity Guidelines in the UK: Review and Recommendations (Chapter 4.3, p43). London:DoH; 2010
3.Swedish National Institute of Public Health. Physical Activity in the Prevention and Treatment of Public Disease.(Chapter 24, p331). Sweden: SNIPH; 2010
4.Department of Health. CG90 The NICE Guideline on the Treatment and Management of Depression (Updated Edition)(Chapter 7.5, p213). London: The British Psychological Society and the Royal College of Psychiatrists; 2010
5. Franz SL, Hamilton GV.Effect of exercise upon the retardation in condition of depression.Am J Insanity 1905;62:239–256.
6.Mead GE, Morley W, Campbell P, Greig CA, McMurdo M, Lawlor DA. Exercise for depression. Cochrane Database Syst Rev 2009;Jul 8;(3).
7.Rethorst CD, Wipfli BM, Landers DM.The antidepressive effects of exercise: a meta-analysis of randomized trials.Sports Med 2009;39(6):491–511.
Competing interests:
No competing interests
14 June 2012
Jo Larkin
Sport and Exercise Medicine Trainee
Dr Sarah Davies, Dr Mike Loosemore, Prof Hugh Montgomery.
Rapid Response:
Re: Facilitated physical activity as a treatment for depressed adults: randomised controlled trial
To The Editor:
We observed with dismay the media coverage of Chalder and colleagues’ paper reporting the lack of efficacy of an intervention to encouragephysical activity in treating depression[1]. The Daily Mail was not alone in reporting that ‘Exercise does little to help the symptoms of depression’. But does the trial, as published, support such a view?
The study has an array of methodological flaws many of which are acknowledged by the authors. However, there are more systemic issues. Firstly, if time-based activity targets ‘seemed unrealistic’, then ‘any increase in physical activity, whatever the intensity’ was encouraged. Current recommendations are that exercise should be at moderate (or greater) intensity[2,3], while no data suggest benefits from unstructured low-level increases in exercise – perhaps the reason why NICE support ‘a structured and supervised exercise programme’[4].Secondly, in evaluating success, the use of an(estimated) 1000 METS per week threshold is both arbitrary (in terms of any impact on depression) and unvalidated in its mode of calculation. Many of the subjects also seemed to be taking significant physical activity prior to inclusion – weakening study power to detect an impact. Finally, activitywas not reliably measured: the questionnaire-based recall of activity used in analysis showed (at best) ‘reasonable’ (the authors’ words) agreement with gold standard accelerometry, and poor agreement for more vigorous activity – that perhaps of greatest benefit.
In terms of conduct, between 1/5 and >1/3 of 361 subjects were missing from follow-up at each time point. Three face-to-face meetings and up to 10 telephone contacts were offered, in the hope that five contacts would be achieved by four months. Fully 44% failed to meet even this target.
Thus, an intervention without strong likelihood of impact was incompletely delivered to a depleted group of subjects, many of whom were already active, while changes in vigorous activity were determined using a methodology the researchers showed to have poor validity. Such factors might explain why the authors could only detect ‘some weak evidence of an increase in physical activity levels’ at 4 months. Indeed, only ten more people were ‘active’ in the intervention limb than the non-intervention (8.1% in real terms).
If the study demonstrated anything at all, it is less that a lack of efficacy of exercise in benefitting depressed patients, than that a specific intervention failed to deliver changes in exercise which might have been beneficial. The authors concur, stating it was possible that ‘the increase in activity was not sufficiently large to lead to a measurable influence’.
Existing data do suggest that exercise benefits depressed patients. As far back as 1905, Franz et al recorded the first case series showing the effect of moderate physical activity on the cognitive, physical and emotional conditions of two patients with severe depression[5]. More recent systematic review of robust trials[6] and meta-analyses[7] are confirmatory. The challenge, then, is how most effectively and cheaply to engage patients in moderate-vigorous exercise. The value of the latest paper is that it shows one process which is ineffective in doing so – not that it demonstrates a lack of efficacy of appropriate exercise in treating depression. ‘NHS Choices’ made this distinction clear, commenting that the study “assessed just one type of exercise intervention [our emphasis].’
Why, then, would the BBC run the headline ‘Exercise no help for depression’? Perhaps the answer lies with the BMJ itself. “This carefully designed research study has shown that exercise does not appear to be effective in treating depression", ran their press release – a message reinforced on the BBC Radio 4’s Today programme (audio available at http://news.bbc.co.uk/today/hi/today/newsid_9726000/9726228.stm), an author stating that exercise ‘is not good for treating people… [with] depression’ and that exercise ‘is not appropriate’ in such circumstances.
We do not believe that the paper, as published, supports such a conclusion.
Yours Sincerely,
Dr Sarah Davies, Sport and Exercise Medicine Trainee (London Deanery).
Dr Jo Larkin, Sport and Exercise Medicine Trainee (London Deanery).
Dr Mike Loosemore, Consultant Sport and Exercise,University College London Hospitals.
Prof Hugh Montgomery, Director, UCL Institute for Human Health and Performance.
References:
1. Chalder et al. Facilitated physical activity as a treatment for depressed adults: randomised controlled trial. BMJ 2012;344:e2758.
2.Department of Health. Bull, FC. et al.Physical Activity Guidelines in the UK: Review and Recommendations (Chapter 4.3, p43). London:DoH; 2010
3.Swedish National Institute of Public Health. Physical Activity in the Prevention and Treatment of Public Disease.(Chapter 24, p331). Sweden: SNIPH; 2010
4.Department of Health. CG90 The NICE Guideline on the Treatment and Management of Depression (Updated Edition)(Chapter 7.5, p213). London: The British Psychological Society and the Royal College of Psychiatrists; 2010
5. Franz SL, Hamilton GV.Effect of exercise upon the retardation in condition of depression.Am J Insanity 1905;62:239–256.
6.Mead GE, Morley W, Campbell P, Greig CA, McMurdo M, Lawlor DA. Exercise for depression. Cochrane Database Syst Rev 2009;Jul 8;(3).
7.Rethorst CD, Wipfli BM, Landers DM.The antidepressive effects of exercise: a meta-analysis of randomized trials.Sports Med 2009;39(6):491–511.
Competing interests: No competing interests