PHOTO: Guy Leschziner in his study, surrounded by books on neuroscience and sleep, reflecting on the complexities of the human brain.
Neuroscience Sleep Medicine And Human Experience
Guy Leschziner discusses the science of sleep, neurological conditions, sensory perception, and morality, blending rigorous research with human stories to make complex neuroscience accessible and compelling for all readers.
Guy Leschziner has a remarkable ability to navigate the shadowy terrain where the mysteries of the human brain intersect with the fragile rhythms of sleep. His work, spanning The Nocturnal Brain, The Man Who Tasted Words and Seven Deadly Sins, invites readers into worlds that are at once intimate and uncanny, revealing how profoundly our minds shape our realities. There is an immediacy in his writing, a quiet insistence that the science of neurology is inseparable from the human stories that animate it.
In his clinical practice, Leschziner witnesses the startling ways in which neurological conditions can transform lives, yet he conveys these insights with a gentle clarity that never sacrifices complexity. His narratives are informed not only by rigorous scientific knowledge but also by a sensitivity to the people behind the diagnoses—their fears, their humour, their extraordinary experiences. Through his books, the ordinary reader is guided into the extraordinary workings of the mind, exploring sleep disorders, sensory perceptions and the very biological roots of morality.
There is a reflective quality to Leschziner’s writing that lingers beyond the page. Cases of narcolepsy, synaesthesia, and the more surreal episodes of nocturnal speech challenge our assumptions about normalcy, prompting us to reconsider the boundaries between the body, the mind, and the self. In addressing themes as diverse as perception, behaviour and “sin,” he illuminates the subtle interplay between biology and morality with both insight and compassion.
At a time when the dissemination of scientific information is both easier and more perilous than ever, Leschziner demonstrates the profound value of thoughtful, accessible communication. He reminds us that understanding the brain is not merely a scientific pursuit, but a deeply human one—an exploration that enriches our grasp of what it means to live, to think, and to dream.
What first drew you to the study of sleep and the brain, and why do you think these subjects continue to fascinate the public?
Like many of my neurologist contemporaries, my fascination in the world of neurology was piqued by Oliver Sacks’ seminal work, The Man Who Mistook His Wife For A Hat. The descriptions of the terrible and wonderful ways we are vulnerable to changes within our brains was mind-blowing, and made me aware that every aspect of who we are – our memories, our personalities, our cognitive abilities, how we move, how we sleep, how we interact with the world – all of these are entirely a result of the functions and structures of our brains. I think this is why the public, not just neurologists and neuroscientists, have a deep curiosity around this subject – how this lump of fatty tissue, a couple of pounds in weight, defines everything of who and what we are.
In your clinical work, which sleep disorder do you find patients struggle with the most, and why?
Anyone who has ever suffered from sleep issues will know how sleep affects every aspects of our waking lives, sometimes with devastating results. But perhaps those conditions that are most difficult to cope with are those individuals with narcolepsy, who are seized by sleep, sometimes even while being very active, accompanied by vivid dreams, hallucinations, sleep paralysis and loss of muscle strength triggered by strong emotion. Kleine-Levin syndrome is another condition that is very difficult to live with. These usually young individuals are normal for weeks or months, but their lives are interrupted by periods of day or weeks of profound sleepiness, confusion, behavioural changes and huge increases in appetite. Their condition acts as an entirely unpredictable brake of their day-to-day lives.
How do you balance the scientific detail in your books with the need to make the material accessible and engaging for general readers?
This is one of the biggest challenges in writing these types of books. The aim is to be informative and scientifically accurate, while simultaneously maintaining story-telling. There is such a wide range of readership for my books, from the general reader without any particular scientific background, to doctors with a full grasp of physiology and anatomy. The key I think is to keep it human, to weave the science into the human experience of living with these conditions. This is why I write about, and with, my patients, most of whom participate in what I write about them. As a result, I do not need to anonymise the individuals described, nor do I strip them of their words and views.
What was the most surprising or unusual case you encountered while researching The Nocturnal Brain?
Each and every one of the cases described in the book are startling and informative in their own right. However, the most surprising case for me was the man who complained of graphic sleep-talking, his nights filled with him describing extramarital affairs and criminal acts. Ultimately, we discovered that his partner was making the whole thing up!
In The Man Who Tasted Words, you explore the senses—how do these sensory misperceptions challenge our assumptions about reality?
When you encounter patients who have never experienced pain, or whose vision is afflicted by continuous hallucinations, it does make you question that nature of how we all experience reality. In many of the cases I describe, very small changes to our bodily functions – through genetics, injury or chemicals – can turn our understanding of the world around us on its head. It makes you realize that our reality is a reconstruction of the world by our brains, and relies entirely upon the structure and function of our nervous system. When you encounter people with synaesthesia – a trait rather than a disease or disorder, where there is cross-talk in the brain between different senses, such as hearing and vision, or touch and smell – you become aware that there are people with “normal” brains everywhere, whose experience of reality is very different from your own.
Your recent book on the Seven Deadly Sins examines biology and morality—how do you think neuroscience reshapes our understanding of “sin”?
In the neurology clinic, we often see individuals with neurological diseases whose “moral compass” has been skewed, who exhibit dramatic changes in their behavior that could be described as sinful. These people are at the extremes of the human experience, but as I write in the book, for all of us, the behaviors that are characterised by the Seven Deadly Sins are hard-wired into us, and have important biological imperatives. Crucially, there are factors beyond our control, like our genes, the environment while we are in the womb, even viruses, that will influence these aspects of our personalities. And if that is the case, then for all of us, how much can our behaviour be ascribed to our moral worth, and how much to our biology? For some people the answer is very clear, but for most of us there are blurred boundaries between the biological and the moral.
With your background in both clinical practice and public communication, how do you see the role of doctors evolving in educating the wider public?
This is especially important in the current age, where the public have access to huge amounts of health information, some accurate, some wildly incorrect and destructive. Our responsibility is to make sure that what is out there is helpful, correct and not scare-mongering. Unfortunately, the nature of social media facilitates the dramatic, the attention-grabbing, the often fallacious. Our role, a difficult one, is to combat this misinformation.
What advice would you give to other authors who wish to write about complex scientific or medical subjects for a mainstream audience?
When I write, I think of the reader I have in my mind – someone without a strong scientific background but with a keen interest. I try to write for this reader, to ensure that I am not overcomplicating the science, but also avoiding dumbing it down. And then when I have written something, to get several people who have no scientific knowledge to read it. After being in the world of medicine for over 30 years, it can be easy to make assumptions about what people know and don’t know, sometimes incorrectly.
