From sexsomnia to birdseed snacks, author Guy Leschziner explains the mysterious realm of sleep

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One patient with sexsomnia was convicted of rape after assaulting his ex-partner in his sleep. Another diagnosed with sleep-eating woke up to find he had polished off a bowl of his pet’s birdseed, doused in salad dressing. And another man with cataplexy, a condition specific to a type of narcolepsy that is characterized by sudden loss of muscle tone, collapsed in a heap every time he told a joke.

These are a sampling of the extraordinary cases Guy Leschziner sees as the clinical lead of one of Europe’s largest sleep centres at Guy’s Hospital in London.

Reminiscent of the works of the late British neurologist Oliver Sacks, Leschziner’s new book, The Nocturnal Brain: Nightmares, Neuroscience, and the Secret World of Sleep, explores how the brain functions – and what happens when it doesn’t – through the remarkable stories of his patients.

The brain does not simply shut off when we sleep, and turn on again when we wake, he explains. Rather, various parts of this complex organ can be in different stages of sleep and wakefulness at the same time.

As he tells The Globe and Mail, the most extreme examples of disordered sleep can provide a window into what goes on in the brains of us all while we slumber.

What drew you to a career in understanding sleep disorders?

My background is in epilepsy, but there is a significant commonality between sleep medicine, from a neurological perspective, and epilepsy.

As a medical student, I came across a paper written by Francis Crick, one of the discoverers of the structure of DNA. That for me was the first realization that actually, we really don’t know – certainly at that time, we had very little inkling of what it is that is happening in a third of our lives. It kind of beggars belief really. So, that was really the start of an interest in sleep.

Many of the patients in your book put off getting help because they felt ashamed, or shrugged off their sleep problems as mere quirks until they became serious. What common misconceptions about sleep disorders do you want to dispel?

The first is that these conditions are not treatable, because many of them are – not all, but many of them. And lot of these sleep disorders are seen as objects of comedy, whereas actually, they can have life-changing, devastating consequences.

In some respects, people have a very delayed path to getting a diagnosis or treatment because they don’t necessarily come forward. And some of the delays of diagnoses have to lie at the feet of physicians because as a community, historically, we have been very, very poor about knowing anything about sleep. Even now, the average teaching in medical school about sleep is about two to four hours.

How does understanding the exceptional patients help you treat the more common cases?

By looking at these extremes, one begins to understand what the underlying mechanisms are for these disorders, and then, one begins to see the relevance for everybody, actually. The fact, for example, that we understand from these patients who are extreme sleepwalkers that our brains can be in different stages of sleep at the same time is applicable to all of us.

We’re all potentially at risk not only of these disorders, but even whilst we’re awake, we’re beginning to understand the brain can be in different stages of wake or sleep. So, when people are sleep-deprived, there are probably very small areas of the brain that are constantly sleeping even whilst they’re wide awake.

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You discuss examples of sexsomnia and cases such as Kenneth Parks of Ontario, who was acquitted of murdering his in-laws while asleep in 1987. How can someone who is typically non-violent commit rape or murder in their sleep?

The brain state in non-REM parasomnia is essentially a brain state whereby the brain is not working properly at all, in the same way that someone who has taken a whole load of drugs or who has had a severe brain injury and is very agitated and confused can undertake these actions that are completely out of character.

In many people with non-REM parasomnias, that behaviour is, in part, driven by the fact that frontal lobes, which are part of the brain involved in rational thinking and inhibition of our more primitive, basic acts like violence or sexual disinhibition, remain asleep. Essentially, the brain is acting independent of its conscience.

There’s a massive industry out there of apps, mattresses, pillows and other products to help people sleep better. What are your thoughts on how to navigate this vast market?

In contrast to drugs or medical devices, many things in the consumer marketplace really don’t have any evidence behind them whatsoever. For a physician, that’s always a deeply uncomfortable position to be in. I constantly get people asking me, “What mattress should I sleep on? What pillows should I use?”

The answer to that is there is no rule and everybody is different, and you need to work out what works for you. And you also need to do that in a similar way as you approach any other aspect of your consumer behaviour, which is do your research, try things out, and don’t get ripped off.

This interview has been condensed and edited.