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Dr Guy Leschziner – The Nocturnal Brain: Nightmares, Neuroscience, and the Secret World of Sleep

Posted in Sleep Series,Special Feature on 17th Dec 2021

I interviewed Dr Leschziner in September 2020, about his new book The Nocturnal Brain. It was a virtual interview, Dr Leschziner at work, in scrubs, and myself from home.

I know Dr Leschziner as I have been a Registrar at Guy’s and St Thomas’ Trust where Guy is a Consultant. I was delighted to read his book, which I found revelatory in terms of my own clinical approach to sleep.

Ann Donnelly, ACNR Co-Editor

AD: Hello, thank you for contributing to ACNR and allowing me the time to interview you. I would like to begin by asking you what it was like to be a full time Neurologist and then also become an author? How did it come about?

GL: A book was never something that I ever had any intention of doing. I had no particular desire to do a book. I ended up doing this radio series for BBC Radio Four on sleep disorders ( After that went out, I got a phone call from a literary agent who asked, “Have you ever thought about writing a book?”

At first I said “No, I don’t have the time.” He approached me just before the Christmas period, and he said, “You’ve got some days off. Why don’t you just sit down and do a sample chapter and see whether you enjoy doing it.”

I sat down for a few days and thought about it. I enjoyed the process and in a strange kind of way, I found it quite mindful. It distracts you from all the stresses and strains of clinical life and you switch off. You focus on something, okay, that’s related to your day, but it uses a different part of your brain and makes you think about things in a different way.

I wrote the book in about five or six months at weekends, in the evenings and any sort of spare moments and found it enjoyable. The aftermath of writing it has been enjoyable as well.

AD: What did you do when you encountered your blank page, did you just dive in and get on with it? It sounds like you were sort of cajoled into it and then you got into the flow. You mentioned Oliver Sacks in your introduction. I’ve always thought in his books, that he doesn’t depict a realistic reflection of the life of a typical Neurologist, because he really got to know his patients outside of the hospital setting and formed deeper relationships with them. Was this a unique opportunity for you to do that in a way? Did you get to know them more than you would ever have done otherwise?

GL: Yes. He (Oliver Sacks) managed to spend an inordinate amount of time with patients and that’s a sort of luxury that the modern NHS Neurologist doesn’t really have. The advantage of writing this book was that these were patients who, for the most part, I’d already had a long diagnostic or therapeutic relationship with, but I got to know them a little bit better because, quite frankly, when we are in a 30 minute appointment, we don’t discuss many of the aspects of their life and how their disorder interacts with that life.
We don’t discuss many of the family and social issues that we perhaps should do if we have more time. So this was a fantastic opportunity to meet some of them outside the clinic room.

AD: Absolutely. So that must be enriching going forward with your interactions with those patients.

GL: Yes, absolutely. It was a real privilege and I think that, some of the people who I wrote about in the book, some of the patients are the same patients that I interviewed for the BBC series. I will have interactions with some of them outside of the clinic room even now, because you do form strong relationships with people.

AD: That aspect of your book was interesting, and then from another perspective, you went to look at papyrus from the Egyptian times and examined the history of sleep. So you had a chance to get to know patients, but you also immersed yourself in the history of sleep. Was that because of the book or was that something you would have done anyway?

GL: It’s a real indulgence to be able to email the British museum and say “I’d like to examine this old papyrus, which I know you’ve got in storage. Is there any way that I can have a look because I’m writing a book?” It was quite a lovely thing to be able to do.

AD: Going back to interaction with patients, actors have the fourth wall, which they can sometimes break. In a way there’s that wall we have between our patients as doctors. For the book, in a way, you’re going around that by meeting patients outside of clinic. Was that in any way complicated at any time?

GL: No. One of the biggest issues that I had to address in writing the book, was that I did not want to threaten my therapeutic relationship with my patients by writing about them. So I tried to include them as much as possible in the process of writing the book. That may have been as little as saying to them, look, here is the chapter, if you are uncomfortable with anything that I write about, or if you want to phrase it in a different way, then let me know, and I will do that. I was upfront with them, right from the start.

AD: That’s the opposite of what most writers supposedly do because writers in general are famous for plundering their friends and family for copy. So, would you consider that you had a therapeutic approach to the way you were writing as well?

GL: Essentially I was telling their story. It was their story to tell, I was telling it and putting it into context, putting it into a scientific, or as you say that historical context. I wanted to ensure that that was the relationship, that they didn’t feel that I was stealing their story, for them to know that they were still the tellers of their story.

AD: I liked the way each chapter structure begins with a person, then it flows into more general discussion about sleep and the neuro biological basis. You always return to the patient and your conclusions about that. Do you think that in writing this book, you came up with new concepts and were you able to synthesise these big ideas by taking all these strands together and having to write it as a book?

GL: I didn’t come up with any new ideas, but I think that’s certainly formulated more clearly my views on aspects of clinical sleep medicine. I perhaps analysed more carefully what it is that I do within my clinical practice. In that respect, it was a process that was not only good for me, psychologically, but good for my development as a clinician.

AD: As a Neurologist, especially somebody who works with patients with traumatic brain injury (TBI), I learned so much from this whole book. I wasn’t aware that impaired sleep is classed as a possible carcinogen by the World Health Organization (WHO) and I wasn’t aware of the REM sleep association with hypothermia. Having read your book it seems like sleep is an under-explored part of neurology.

GL: The way that sleep medicine was presented to Neurologists was as predominantly ‘pure’ Neurological disorders, like frontal lobe epilepsy, restless leg syndrome, and narcolepsy. That was the breadth of Neurological interest or expertise in sleep.

Within my own clinical work, which is to make sleep part of a big multi-disciplinary centre, rather than within the confines of a silo of Neurology or Psychiatry – the goal is to try to broaden out that interest on that relevance, not just in Neurology, but to every single specialty.

We now understand the relevance of sleep to TBI patients in terms of cognitive abilities, in terms of behavioural issues. It is also relevant to migraineurs, to the epilepsy population – and a whole range of patients with functional neurological disorders.

AD: The book really beautifully illustrates a lot of sleep pathology. There are things that I think in a way, sleep and hunger are things that we are learning a lot about in terms of environmental and genetic influence.

In the book you discuss a young boy with an abnormal sleep wake cycle, and it was fascinating to think that something so integral to our development can be intrinsically abnormal.

We have been talking a lot about sleep pathology, but I’m sure in Los Angeles, there’s a whole group of people who were thinking “How can we hack sleep,” too? With lucid dreaming, for example, I can imagine there are ways that that could be used to enhance performance and things like that, but how much are we looking at sleeping in the well population?

GL: I think that there is a great deal of attention among certain areas of the scientific community about optimising sleep, particularly when it comes to thinking about ageing. You’ll be aware of this growing literature that suggests that slow-wave sleep in particular is involved in metabolic regulation of the brain. It may be that sleep may be an independent risk factor for dementia. We are a long way away from clearly demonstrating a causal relationship, but as a result of that and as a result of our knowledge of sleep and the regulation of, for example, the immune system or metabolic aspects of health like hypertension, people are looking at sleep as part of – for want of a better term – ‘wellness.’

I can definitely imagine how people will be thinking, “How can I harness the potential of this in some way?” There are some interesting developments. There are teams looking at potentiating slow wave sleep looking at brainstem evoked potentials and using pink noise. Pink noise is like white noise, but it has a slightly different spectrum of sound. They have timed the frequency of noise to slow wave brain oscillations and they see whether or not there’s an improvement, both in the depth of slow wave sleep and whether or not there’s an improvement in cognitive tests. Early evidence suggests that there is some improvement in slow wave sleep. There are some so far non-significant improvements in various aspects of cognitive testing.

So that’s one example of hacking. I write about how it is possible to stimulate increased lucidity of dreaming by stimulating the parts of the frontal cortex. Could that be a way of first of all, having a more interesting night’s sleep, and secondly, could that facilitate learning? Could that facilitate clinical treatments like treatments for nightmare disorder in the context of PTSD, for example? There are a lot of people paying close attention to the technologies that are now available, that may allow us to potentiate certain aspects of sleep.

AD: Having read this book, I feel like I’ve probably not really touched the surface of most of my patients’ sleep difficulties and I’m probably missing a lot and I’m probably not prescribing. How can we improve our clinical approach to sleep?

GL: For a Neurologist essentially if somebody reports poor sleep, then what you need to understand is – is this patient sleep deprived? Is this patient an insomniac, or could there be some biological sleep disorder underlying that? You don’t necessarily need to work out what the biological problem is.

If somebody says that they feel sleepy, but when given the opportunity to sleep can’t, then that suggests they’ve got insomnia. If they feel sleepy, but when given the opportunity to sleep, they sleep, and when they increase their duration, they feel better – typically somebody who has a lie in at the weekend – it means that they are behaviourally sleep deprived. That is probably the commonest clinical picture of all. Anybody who is excessively sleepy, despite fully adequate amounts of time in bed, needs investigation for a sleep disorder.

AD: I’ve been a Junior Doctor and I’ve been a parent to young children. After years of disrupted sleep, what happens to your intrinsic sleep architecture and can you ever get back to where you were? It’s a light-hearted question really.

GL: I think most parents will say that they’re never the same again, and we all get a bit older as well, so it changes. We don’t have another version of ourselves without children which we can compare to. The genetic contribution to our sleep, both in terms of our sleep duration, our sleep requirement, our resistance to sleep deprivation, our chronotype – pretty much every aspect of sleep has a strong genetic determinant.

Whether our sleep is fundamentally altered by a long period of disruption – I think even that is predetermined because if you have a tendency towards poor quality sleep or a tendency towards insomnia, then having your sleep altered by on-calls and children probably means that your sleep will never be the same again.

AD: How much is technology influencing the quality of our sleep?

GL: Hugely. Work is encroaching on our lives much more than it used to, and that is to a large extent through technology. Both of those things are conducive to worsening sleep.

AD: How big a role does caffeine play or is that partly genetic as well?

GL: I think it’s certainly genetic, about 10% of individuals carry a mutation which means that caffeine does not affect their sleep whatsoever. Once again it depends on how good your brain is at initiating and maintaining stable sleep. So if you don’t have that particular polymorphism and you are sensitive to the effects of caffeine and depending on what your background sleep is and how much we drink.

AD: We’re coming towards the end of the interview, so I think what is really fascinating to me is that you’ve managed to write while working full time as a Neurologist. It’s beautifully written, it flows and the structure of it is really easy to follow. It’s just a pleasure. I feel it’s also opened the door to learning more. Do you think that we need to be doing a bit more about sleep as Neurologists? What do you think Neurologists will be doing with sleep in 10 years time?

GL: There will be a lot more research into the association between sleep and Neurological disorders. As technology improves and we are better able to study sleep at home, the threshold for investigating people with sleep disorders will be lower. It will become more decentralised. The Neurologist in a standard outpatient clinic will be more easily able to study sleep in a clinical way, but that does need to be accompanied by education in sleep and I guess that’s the job of people like me and my colleagues to do that.