Depression, exercise and the impact of research

Guest blog by Dr Joseph Lightfoot and Mr Charlie Fry

The recent BMJ publication Facilitated physical activity as a treatment for depressed adults: randomised controlled trial stirred the medical world and the media with the claim that exercise has no impact on depression. This supposedly myth-busting paper was shared, tweeted, commented upon and even appeared in a 10-minute slot on BBC Radio 4.

However, it also received a large degree of backlash. Many doctors, physiotherapists, psychiatrists and other healthcare professionals critiqued the paper, and disagreed with the authors’ (Chalder et al.) claims. These critiques are among the comments on this rapid response section of the BMJ website HERE.

A Critique

A letter recently published in the British Medical Journal summarises these critiques – which you can view HERE.

In summary, the research paper had several major flaws including validity of the exercise intervention and rate of follow-up. The only conclusion that can be drawn from the paper is that the exercise intervention they employed had no effect on depression – not exercise as a whole. Yet via a press release from Bristol University and as aired on BBC Radio 4, the overriding, propagated message is that exercise does not appear to be effective in treating depression”.

As Dr Mike Loosemore, Sports and Exercise Medicine Consultant added:

“The paper doesn’t show anything of the sort. There is a mismatch between the results and what the authors are concluding and as such what the media is spreading to the population.”

Photo courtesy of Janey Kay (Flickr CC)

What Does Other Research Say?

There is a wealth of research from the last three decades that provides contrary evidence: that exercise is effective in treating depression. For example, a paper published in the BMJ in 1985, reported that moderate aerobic activity was sufficient to produce an antidepressant effect at a six and nine week follow-up (1).  This is supported by another study undertaken between 1998 and 2001 that also found exercise to be effective in treating mild to moderate depression (2). Finally, a paper looking at exercise as an intervention in severe depression, positively associated exercise with significant therapeutic benefit (3).

We also must not forget exercise is a “polypill” and has a beneficial effect on other co-morbidities and quality of life, which the authors of the recent depression paper also conclude.

The Impact Of Research

Outside of the debate about exercise and its effectiveness in treating disease, this recent paper and resulting media attention illustrates an important point. In making certain claims we have to understand the impact these widely broadcast messages may have on individuals, including the lay public.

The 10-minute broadcast on Radio 4, which you can listen to HERE, reached an estimated seven million people. It contained a very clearly delivered the message that exercise is not good for treating people with depression.

No comment was made on the validity of the study design, nor was their mention of the previous research that demonstrates exercise’s benefits for helping patients with depression.

According to NHS clinical knowledge summaries, each year 6% of adults will suffer an episode of depressive symptoms. Out of the seven million listeners therefore, 420 000 individuals may have suffered in the past 12 months or indeed be currently suffering depressive symptoms.

Suppose we assume only 25% of listeners take the advice and adapt their exercise habits, then that’s 105 000 people who have altered their behaviour. This is a conservative estimate and doesn’t take into account further propagation of this information by individuals to others who might have or be currently suffering from depression.

In drawing conclusions and then relaying them to the media, and thus to the general public, we need to consider the consequences of our messaging – whatever the topic.

Conclusion

The researchers’ conclusions are heavily questionable, but what is more concerning is the way that bold claims extrapolated from the research were distributed so widely throughout national media.

We welcome new research that goes against the grain, and offers evidence to refute commonly held beliefs, but to do so the research needs to be detailed and any conclusions drawn need to have sufficient support from the evidence.

The larger issue here is the lack of training about the benefits of exercise (for all conditions, not just depression), and just as importantly advice on implementation.

To illustrate this with a crude example, if we, the authors, were to perform neurosurgery for a year, and you audited our results, you could conclude that neurosurgery was a poor intervention, when in fact the correct answer is that we have not been trained to perform that intervention effectively.

In order for exercise to be utilised as a successful intervention, healthcare professionals require more training.

Final Words

Many healthcare professionals have been campaigning for the increased use of exercise as a treatment modality, and there is ample research that proves its effectiveness not only for depression but also for many other diseases as common as diabetes, and as specific as glioma.

The damage this paper has done for the movement to improve people’s activity level is hard to predict. Rather than reducing the number of those undertaking exercise, we hope its inaccuracy provides a springboard from which further education of both the medical establishment and the general population, ultimately leading to a happier, healthier nation.

References:

(1) Martinsen EW, Medhus A, Sandvik L. 1985. Effects of aerobic exercise on depression: a controlled study. Br Med J (Clin Res Ed). July 13; 291(6488):109.

(2) Dunn Al, Trivedi NH, Kampart JB et al. 2005. Exercise treatment for depression: efficacy and dose response. Am J Prev Med. Jan:28(1):1-8.

(3) Babyak M, Blumenthal JA, Herman S et al. 2000. Exercise treatment for major depression: maintenance of therapeutic benefit at 10 months. Pyschosom Med. Sept-Oct:62(5):633-8.

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Dr Joseph Lightfoot MBChB BSc(Hons) (www.jplightfoot.com) graduated medical school in 2012. He is currently working as a coach and researcher and has worked with a number of international teams, including the England under-19 lacrosse team. He is also the founder and a director of the Move Eat Treat campaign, which is campaigning for an increase in the use of lifestyle advice in medicine. For more information about the Move Eat treat campaign, visit www.moveeattreat.org.

Mr Charlie Fry is a third year medical student at the University of Bristol, currently about to start his clinical placements. He has competed to regional level in hockey, athletics and squash and has undertaken work experience at sport injury clinics since 2010. He hopes after graduation to specialise in sports medicine.

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