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Reversibility, Colds, and Neurosurgery

By Jonny Pugh

This blog was originally published on the Journal of Medical Ethics Blog


Happy new year to readers of the blog!

I always approach the new year with some trepidation. This is not just due to the terrible weather, or even my resolution to take more exercise (unfortunately in the aforementioned terrible weather). Instead, I approach January with a sense of dread because it is always when I seem to come down with the common cold.

In my recent research, I have been interested in the nature and moral significance of reversibility, and the common cold is an interesting case study of this concept. In this blog, I will use this example to very briefly preview a couple of points that I make in a forthcoming open access article about reversibility in the context of psychiatric neurosurgery. You can read the open access paper here.

Are Colds Reversible?


Consider the following question: Are the effects of the common cold reversible? This may seem like a very easy question to answer. Of course it is! Even when you are unfortunate enough to come down with a cold, in the vast majority of cases the symptoms are only temporary.

If you sympathise with this response to the question, then perhaps you think that claims about whether some state of affairs is ‘reversible’ simply concern whether or not the change in question is permanent. On this understanding, the effects of the common cold are reversible, just in the sense that they do not last forever.

However, this may not be the only sense in which we might be interested in the concept of reversibility. Suppose that you are stricken in bed with a headache, aches, and a temperature. A caring friend brings you plenty of water and paracetemol to manage you symptoms, but you still feel terrible. Imagine that your friend tells you ‘don’t worry, the effects of this cold are entirely reversible’. In response, you might reasonably ask for something to be done to reverse your symptoms now. Of course, the likely reply to this request is that there is not much that can be done to determine precisely when the symptoms will fully abate. It is really just a case of waiting until your immune system fights off the infection.

In such a position, I think you might question whether the effects of the common cold are reversible in all the senses that matter. In some cases, our interest in reversibility may simply concern the duration of some changed state of affairs; will it be temporary or will it be permanent? Call this sense of reversibility, ‘reversiblity simpliciter’. In contrast, we may sometimes be interested in reversibility in a stronger sense. That is, we may be interested not just in whether some changed state of affairs is only temporary; we might also be interested in whether or we can control both whether and when the changed state of affairs in question obtains. Call this ‘full-blooded reversibility’.

In the example of the common cold, we may clearly say that its effects are ‘reversible simpliciter’. However, it is not clear that they are reversible in the full-blooded sense; and we might sensibly lament this fact.


Reversibility and Deep Brain Stimulation


The common cold is a somewhat trivial example to illustrate these different senses of reversibility. However, questions about the nature and moral significance of different kinds of reversibility are currently of great importance in the context of psychiatric neurosurgery.

At present, there are a growing number of experimental studies investigating Deep Brain Stimulation for some treatment-refractory psychiatric conditions (including depression, anorexia nervosa and obsessive compulsive disorder). Concurrently, there is also increasing interest in the experimental use of certain brain lesioning surgeries to treat these conditions. Given the current paucity of evidence regarding either of these interventions in the psychiatric context, there is considerable debate about whether DBS is a preferable to brain lesioning approaches in the psychiatric context.

Crucially, those who claim that DBS is preferable to brain lesioning approaches often support their view by appealing to the apparent reversibility of DBS: They claim that the effects of treatment can be reversed by ceasing stimulation or even explanting the DBS system. Yet, this line of argument in support of DBS has recently been criticised, as we begin to learn more about some of its permanent effects.

There is then, a salient moral question here with very important practical implications for future of psychiatric neurosurgery: To what extent is DBS reversible, and why should that matter?

This is a question I take up in a forthcoming paper in the JME. Part of my argument in this paper is that in order to answer this question, we need to adopt a nuanced understanding of the different senses of reversibility I outlined in the first part of this blog. Furthermore, we need an account of why these different senses of reversibility might matter morally. I conclude that DBS may be said to be reversible in a sense that matters morally with regards to comparisons between DBS and brain lesioning approaches in experimental psychiatric neurosurgery.


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