“Sod the facts, it works for me.”

The title above is a summary in fewer than 10 words of what Guardian journalist and pop-psychology author Mark Rice-Oxley has said in 630. The subject of Rice-Oxley’s lifestyle article is a recent paper on clinical depression which shows that physical exercise does not alleviate the condition, or at least it does not do so to the extent that antidepressant drug use and other therapies can be reduced.

Needless to say, Rice-Oxley, a depressive whose self-medication included publishing a memoir of his experience with the illness, does not care for what the scientists have to say. But at least in his opening sentence Rice-Oxley acknowledges the challenge he faces…

“The problem with arguing with science is that it is often an uneven contest, a bit like hitting a steamroller with a stick of rhubarb. You have emotion, anecdotal evidence, a sixth sense; they have hard facts.”

This, however, doesn’t stop Rice-Oxley elevating his emotion, anecdotal evidence, sixth sense and rhetorical skill over the facts, and twisting the research results to argue, in effect, that scientists are now saying that exercise is useless for depressives. They are not. Rice-Oxley and those of his memoir readers who wrote to say that they feel better after a walk, jog, swim, spot of gardening or whatever know better, and thus are universal truths born.

There then comes another rhetorical trick – admit that you’re wrong, and carry on regardless…

“So how to reconcile the anecdotal evidence with the empirical science? Perhaps both are slightly mistaken. We depressives are not to be trusted when we declare what is good for us. Often there are too many variables changing to know which is the one that is helping. It seems to make sense that exercise helps, but perhaps that’s a virtuous circle. We think it’s going to work, so it does.”

So Rice-Oxley is capable of rational thought. Excellent. Well, maybe not, for he goes on to illustrate his counterfactual argument with the example of a man who got seriously into triathlon sport, and did the London Marathon. This chap felt so good as a result of his efforts that he came off the antidepressants. Doubly excellent!

Now where to start? For one thing, the scientists behind the latest BMJ study are clear in their conclusions, even if these are framed in turgid medical science prose. What emerges from the study is that the kind of exercise considered feasible for the average person does not have a significant clinical effect on depression. Going for a walk in the woods will make even the most grumpy old puss cheer up a little, but if the underlying cause of his grumpiness is the mental illness known as depression, the exercise itself will not help in the medium to long term.

Hard core athletic activity is another question. Sustained aerobic and anaerobic activity can lead to dramatic biochemical and physiological changes in the body, but even there we cannot say that it works to alleviate clinical depression. It may just be an extreme example of the ‘I feel pleasantly knackered’ effect, what with soaring endorphin levels. Sport as a narcotic drug, if you like.

Let’s be clear about this: the BMJ study, which is based on a sample of 361 subjects, is methodologically and statistically rigorous. With that sample size, the study is highly unlikely to have missed anything of significance, with any undetected effects too small to have had a measurable outcome on the subjects.

Another way of paraphrasing Rice-Oxley’s article: ‘I don’t know much, but I like what I know.’

Further reading

Chalder et al., “Facilitated physical activity as a treatment for depressed adults: randomised controlled trial”, BMJ 2012, 344 (2012)