Sleep is good for you, we all know that. But just how essential it is, we often overlook, says Van Heugten. “In our society, it is widely accepted to crave a cup of coffee to wake ourselves up. While that is actually the first sign of lack of sleep. If you need caffeine to get through the day, if you find it difficult to get out of bed in the morning, and you don’t feel rested, then sleep is not what it should be.”
The fact that someone is grumpy or impatient because of lack of sleep, is one thing. But exhaustion plays a huge role in serious accidents, Van Heugten writes. For example, the chance of a car accident is three times greater when you have had less than five hours sleep. Also, in the case of the nuclear disaster in Chernobyl, employees had been working shifts that lasted longer than thirteen hours.
In addition, our mental well-being also suffers because of it. “I would even go as far as to say that sleeping problems play a role in every mental health disorder. It would be a good thing if it were to become a standard question when someone with problems visits a GP or a clinic: How well do you sleep?”
Research into this (by Van Heugten and by others) has mainly focused on the presence of psychotic and dissociative symptoms. In the case of psychotic symptoms, a person observes things that are not there. In the case of a dissociative experience, a person feels like he or she is disconnected from him- or herself. “From your emotions, your surroundings, your memory. This can be very mild. For example, when you do something on automatic pilot, we refer to that as absorption. Everyone has that every once in a while. In a more serious form, someone takes on a different personality for part of the day, sometimes even without realising it.” This is popularly termed a split personality; a person has, as it were, multiple identities. Food for filmmakers, an example being Split from 2016.
Dissociation occurs in a lot of mental disorders. “Depression, borderline, you name it,” says Van Heugten. “There is also a clearly proven link with sleep. But where dissociation is very difficult to treat, sleeping problems are not. You can do a lot about not being able to sleep.”
That is the second reason why Van Heugten wants more attention to be paid to sleep. “You can follow online sleeping programmes. These can teach you to adopt good sleep hygiene: going to bed and getting up at the same time every day, ensuring you have a quiet, dark bedroom, no caffeine after lunch. If someone really has problems sleeping, this is not enough, but it is the basis. Using cognitive behavioural therapy against insomnia is of little use if someone drinks four cups of coffee in the evening.”
Relaxation exercises and sleep restriction – in which you restrict the time you spend in bed, to ensure that when you are in bed you are actually sleeping – can also help. “Except for the sleep restriction, which is slightly more difficult, these are things that people can implement themselves. The Mental Health Authorities’ waiting lists are very long. Why would you not get started with this in the meantime?”
So, sleeping more and sleeping better. But what happens in those hours? Van Heugten deals with that in detail, including the usefulness of dreaming. She endorses the theory put forward by Sue Llewellyn, emeritus professor at the university of Manchester, that dreams help us learn to recognise patterns. “This enables us to make better predictions about what will happen in daily life.”
In her book, she mentions the example of the predator by the pool. Suppose someone is killed every time a predator comes to the water. The sooner you recognise this pattern, the sooner you know what is going to happen. A dream in which you run away from a bizarre frightening animal by the water, could be helpful here. It reinforces the relation in your memory between observation (a predator) and the consequence (someone dies), so that you will be quicker to act during the day and run away.
Van Heugten would even go as far as to say – “very carefully, without committing myself” – that dreams can show us something that we have not seen yet while awake. There are examples of people who have had ‘predictive’ dreams: they dreamt that they had cancer and later it appeared that they were in fact sick. “Maybe they had already picked up subconsciously on a pattern of minor signals. They correctly interpreted the pattern in their dream, while they hadn’t managed to do so when they were awake.”