The hallucinations that Evelyn describes do not happen during the day; they are very specific to sleep. ‘Normally for me it happens when I’m waking up from sleep. So I could fall asleep for example at midnight, and then an hour later I suddenly wake up.’ As she wakes she is greeted by these awful visions. ‘One time I saw millions and millions and millions of eyes just looking at me, and they were right there in my face.’ She describes eyeballs large and small, like a galaxy of stars floating in the room around her, peering at her. ‘These visions are detailed – very, very detailed.’
For Evelyn, one of the scariest events was seeing a very real image of a recently deceased family member in the room with her, ‘just looking at me. There was no expression. That one completely put me off going to sleep for a while.’
As if these hallucinations are not bad enough, it gets worse. During these visions, Evelyn feels paralysed. Evelyn shudders as she tells me: ‘I’ll be lying there, staring up. I can’t breathe, I can’t move. I try to move, I try to speak, but nothing’s happening. The most that will happen when I’m trying to speak is murmurs, so it will sound like I’m mumbling in my sleep. And then I start seeing these really graphic images – crazy, scary images in my face. And then it’ll go on and on and on.’
She is clearly traumatised by her experiences. ‘The thing is you can’t blink, so it’s not as if I can shut my eyes and hide from it. It’s something I have to look at. And then eventually these things kind of disappear.’
Despite these events happening every night at their worst, she has not got used to them. She has, however, learned how to deal with them. ‘I’ve learned over the months that if I calm myself down – even though no matter how many times it happens to me, it will always be scary to me – the experience will become shorter than previously.’ I ask her if she sometimes tries to fight it. ‘I try to move my arms first because my feet are just stuck, so I try to move my fingers first but nothing’s happening. And then I try to scream and shout but that doesn’t happen. So that’s typically when murmurs and mumbling happens.’
It is not difficult to understand why the combination of being paralysed and having hallucinations of people in the room is so terrifying. Evelyn explains:
It feels like a force is on top of you, stopping you from fighting what you’re seeing and feeling. You feel like you’re going to die. In that moment when you can’t breathe, you can’t move, you’re seeing things that you don’t want to see, dark visions of demons and stuff. You’re pinned down, you feel like something’s attacking you and is stopping your ability to do all the things that keep you alive.
And, for Evelyn, there is no respite during the day either. She has become so terrified of sleeping at night that she fights sleep constantly, resulting in her being very sleep-deprived. As a result, she has taken to napping during the day, but these phenomena have followed her. She now experiences them even during daytime naps. ‘Sometimes it would happen twice in a day when I’d be napping. So when it started happening during my naps, I became even more afraid to go to sleep.’
* * *
It is joked among some of my colleagues that none of my lectures are complete without showing a particular painting by Henry Fuseli, a Swiss artist who lived in the late eighteenth and early nineteenth century. This artwork, entitled The Nightmare, features a dramatically reclining young woman, swathed in a long white nightgown, her head dangling over the end of the bed with her arms extended and hanging down. Her eyes are closed and she looks to be deep asleep. What should be a tranquil scene of a beautiful woman sleeping is made deeply disturbing, however, by a grotesque, ape-like demon crouching on her chest in the darkness. Behind the demon, by the woman’s legs, floats a horse’s head in mid-air, its eyes bulging monstrously in the dimly lit room.
When this painting was first exhibited in 1782, it caused horror and enthrallment in equal measure, and appears to mirror commonly held views of nightmares and folklore that they represent visitations by incubi – male demons who aim to have sex with women in the middle of the night. The concept of the incubus, and its female counterpart, the succubus, were not new, even in 1782. There are references to these demons in Mesopotamian texts from 2400 BC, and these incubi feature in the folklore of peoples around the world, from Germany and Sweden to the Amazon basin, and within many African tribes. Similar descriptions seem to derive from common human experience regardless of race, culture or beliefs.
For me, however, this painting represents many elements of what Evelyn and many other patients describe. The sense of being pinned down, having a weight on their chest, the inability to move, accompanied by deeply disturbing visions of people or ghosts in the room. The horror of this experience is well conveyed in The Nightmare, but the universality of this phenomenon suggests that there is a basis in our biology, in our brains, and we now have an inkling of what causes it.
Evelyn has sleep paralysis and hypnagogic hallucinations. As I mentioned in Chapter 6, our understanding of what sleep paralysis is has moved on a little since Mesopotamian days. With the discovery of REM sleep, that stage of sleep during which we dream story-like dreams, accompanied by paralysis of almost all our muscles, we have recognised that sleep paralysis represents the blurring of lines between wake and REM sleep. Imagine the clutch of a car, disengaging as you smoothly switch between first and second gear. When the clutch slips, and the gears grind, switching between gears is no longer seamless. Similarly, sleep paralysis represents the failure to disengage wake from REM sleep, with features of REM entering into full awareness. The paralysis is switched on, and dreaming starts while you are fully awake. In many respects, it is the polar opposite of the REM sleep behaviour disorder that John in Chapter 3 describes, where paralysis fails in REM sleep. It is easy to understand why visions, or sometimes sensory or auditory hallucinations, may encroach wakefulness if the mental processes of dreaming start before you are fully asleep or continue after you wake up. When sleep paralysis occurs during a sleep study, the brainwaves usually show relaxed wakefulness, but the muscle activity is absent, as would be expected in REM sleep.
Very rarely, sleep paralysis with hallucinations has been shown to be caused by epilepsy, but, unlike Evelyn, in those few cases the visual hallucinations are precisely the same each time they occur. While seizures are usually associated with movement, there are little-known areas in the brain called negative motor areas that, when stimulated, induce weakness or paralysis.
Occasionally, I also see patients with very poor vision who have nocturnal hallucinations. In the darkness, the absence of visual signals causes the brain to create visual images. These hallucinations are termed Charles Bonnet syndrome. Patients will experience sometimes simple visions of lights or geometrical patterns, but often highly complex and detailed visions of people, objects, faces or animals, sometimes in miniature – termed ‘Lilliputian’ in reference to the Lilliput of Swift’s Gulliver’s Travels. These Charles Bonnet hallucinations can last for seconds or several hours, and occur in full wakefulness. In contrast to hypnagogic hallucinations, they seldom cause people fear or anxiety, and are very quickly recognised not to be real. But Evelyn is normal-sighted, and experiences her hallucinations when she falls asleep with the light on. Her symptoms are immediately recognisable as the classical manifestations of REM sleep overspill into wake.
Both sleep paralysis and hypnagogic hallucinations are cardinal features of narcolepsy, the neurological disorder that affects Adrian and Phil. In narcolepsy, the switch that controls wake and sleep, and REM and non-REM sleep, is damaged, and patients with this condition often go straight into REM sleep from wake, rather than after sixty to seventy-five minutes of sleep, as in normal sleepers. In these cases, understanding why you may experience these events is plain to see. But why do people without narcolepsy experience this horrible phenomenon?
It is certainly not rare. Many people experience it at some point in their lives. Research in this field is limited, but it appears that certain factors predispose to s
leep paralysis and the associated hallucinations. Age, gender and race do not seem to be particularly relevant, but from looking at family history and twin studies, there does appear to be a genetic element. More importantly, however, sleep disruption is a common association. Shift work, night cramps, sleep apnoea and sleep quality in general all appear to increase the likelihood, as do certain psychiatric conditions like post-traumatic stress disorder (PTSD) and anxiety. What all these factors have in common is that they make it more likely for you to enter into REM sleep very quickly, or they result in unstable sleep, and perhaps predispose you to waking directly from REM.
For Evelyn, a sleep study does not confirm narcolepsy, nor does she have the marked sleepiness that is the single most important feature in the diagnosis of narcolepsy. But she does have other factors that may contribute.
When her experiences first started, she was working shifts alongside her university studies. ‘I felt like that’s when it first happened,’ she tells me. ‘And then there was a period of time when I didn’t have a job, so I was able to just live freely and do whatever I was doing. In that period of time nothing happened.’ But it was after university, when she began working at a London tourist attraction, that her sleep paralysis and hypnagogic hallucinations deteriorated. ‘When I started there, I only had particular shifts because I was still a student. But especially after finishing [my degree], when you open up your availability and you can say you can work at any time on any day, that’s when things became a bit more hectic and a bit more unbalanced. That’s when the sleeping issues became a lot worse.’
To compound her problems, the fear of these events made her even more sleep-deprived.
I began to hate sleep. And I’m a big fan of sleeping. Anybody that knows me knows that I enjoy sleeping. It was very hard because I just didn’t want to go to sleep any more. I’d spend a lot of my time awake down here [in the living room] doing anything to avoid going to sleep. I’d try not to lie down because I felt like, if I lay down, I’d end up falling asleep. I’d literally try to make myself as tired as possible. I’d watch series on Netflix. I’d watch films until I knew that I was outright tired. I was happy to go to work and wear myself out knowing that when I came home, I’d be tired.
Rather than helping her get better sleep, though, this was probably contributing to the problem.
* * *
Dreams come in all forms. There are obviously recurring themes, but most people recall dreams of different types. So why should the hallucinations that accompany sleep paralysis, that we take to be the mental processes of dreaming while awake, be so similar and universal? The hallucinations are typically of humans or human-like figures in the room, an intruder standing over the bed, and incubus or succubus coming to seduce in the night, being pinned down by another person. One explanation may be that we integrate external sensations into our dreams. A bang of a door in the house may enter our dreams as an explosion; the dog nuzzling your hand becomes a tiger that you are stroking. So perhaps that sensation of paralysis, of having difficulty breathing due to weakness of some of your respiratory muscles, is also integrated into your dream. You feel as if you are being held down, or that something is sitting on your chest, and this sensation influences your dreaming processes.
Ultimately, any theory remains speculative, but the famous Californian neuroscientist V. S. Ramachandran offers an intriguing hypothesis. During sleep paralysis, people sometimes describe out-of-body experiences, floating above the bed observing themselves sleeping, or sensations of movement or distortion of the body. Ramachandran argues that many of these symptoms relate to miscommunication between parts of the brain that represent where our bodies are in space. An area of the cerebral cortex called the superior parietal lobule contains a representation of our own body. In normal life, motor areas of the brain send out signals to move our body, and these movement commands are monitored by the superior parietal lobule. But during sleep paralysis, there is no movement of the limbs, and no feedback about the changing position or movement of the body. This confusion gives rise to a failure to know where your body is in space.
It appears that this representation of your body is hardwired, however, and does not develop as we mature. The concept of a phantom limb, imagining that your body is completely intact despite the amputation of a limb, with resulting sensation and pain from that no longer existing appendage, suggests that this three-dimensional map of our bodies does not change in life. Amazingly, phantom limbs have been described in people with missing arms from birth, which suggests that this map is so hardwired that it is written into our very genes before we are even born. Ramachandran proposes that the classic intruder hallucination is a projection of this ‘homunculus’ – Latin for ‘little man’ and describing this neurological representation of the human body – into our visual world, due to the disturbance of connections between the superior parietal lobule and motor and visual parts of the brain.
He takes the hypothesis one astonishing step further, though, to seek to explain the incubus/succubus hallucination. He proposes that this representation of our own bodies projects to emotional circuitry in the brain and onto visual areas. He and his co-author Baland Jalal write that this network might ‘dictate aesthetic visual preference for one’s own body “type”. This would offer one explanation for sexual attraction/visual preference for certain body morphologies: for example, why humans (generally) are attracted to humans and not dogs, and why pigs prefer pigs as mates to humans etc.’
In support of this, they give the example of people who have an intense desire to have a limb amputated (xenomelia) and who are sexually attracted to amputees. Their powerful feeling that one of their limbs is not part of them is thought to reflect an abnormality in how their homunculus is represented in the superior parietal lobule, and hence they are attracted to people with similar bodies. Jalal and Ramachandran argue that this ‘innate and primal sexual affinity for one’s own “hard-wired” body image’ may explain why hypnagogic hallucinations will often be sexual in nature.
There are also links between sleep paralysis and lucid dreaming, the process of dreaming while being aware of dreaming. During these dreams, people maintain some insight, can exert a degree of control over their dreams, and can access waking memories. Both can be considered states during which greater or lesser degrees of REM sleep are intermixed with wakefulness. In fact, people with sleep paralysis often describe lucid dreaming as well, and evidence from studies confirms this association. Evelyn reports at least one episode of what could be considered lucid dreaming – a dream within a dream.
‘This is going to sound crazy,’ she begins, ‘but I fell asleep and I dreamt about the exact situation I was in, which was me sleeping on the sofa. So my dream was a reality. It was just like normal life was going on, and then in that dream I had sleep paralysis and I woke up from it in the dream.’
In particular, lucid dreaming is strongly associated with out-of-body experiences in sleep paralysis, rather than intruder or incubus hallucinations, leading some researchers to propose that these former phenomena are a feature of positive emotions associated with dreaming imagery, as opposed to the scary negative emotions of hallucinations involving strangers in the room or sexual assault.
* * *
When I visit Evelyn at the family home, the walls are covered in beautiful African batiks, with Swahili banners, family portraits and religious art that represents the family’s Christian beliefs. I sit on the sofa, chatting to Evelyn and her mother, and ask what they both made of her sleep paralysis when it first began to happen. ‘Me and my mum thought it could be some sort of spirit in the room or it could be somebody trying to put a curse on me,’ Evelyn tells me. ‘You just don’t know what to think. So originally we prayed on it, we put holy water on my bed.’
Evelyn’s mother confirms this: ‘I said straightaway: “We need to pray and see whether your problems will fade away.” And I remember we had a priest who was visiting from Uganda. He prayed for her for nearl
y half an hour, saying she had some issue with her.’
People around her were telling her something similar.
We’ve had this conversation so many times. There are films on TV, Nollywood [‘Nigerian Hollywood’] films, that focus around black magic – juju as people like to call it. And especially with something like this, there’s often a conception where if you tell people you’re seeing things, especially coming from a very cultural background – whether you be African or Caribbean or Asian – a lot of people will link it directly to black magic or juju. And they’ll say somebody’s put a curse on you. So when you tell people things like this, often people will say directly, ‘Oh, it’s a spiritual thing.’
Given the nature of these experiences, it is easy to see why. Visitations of people, sometimes dead relatives, or demons at night, out-of-body experiences, being pinned down – these experiences all have a supernatural flavour, and even for people who are not religious, it is thought that these hallucinations may explain reports of alien abductions at night. Evelyn continues: ‘I’ve had a lot of people tell me, “Are you sure it’s not juju? Are you sure it’s not somebody putting a curse on you?’ ”
Evelyn tells a slightly creepy story of a bus journey. She had been chatting to a friend on the phone, telling her about her sleep issues. A woman sitting in the row in front had obviously been eavesdropping.
Then this woman turned around and gave me a note that said: ‘This is really dangerous. If you practise this [referring to the hallucinations as an active spiritual practice] then you shouldn’t, because sometimes people get caught up in practising it and they become trapped. This thing remains with them for ever.’ And I remember I had to cut the phone call off. I said [to my friend]: ‘I’ve got to go. I need to talk to this woman.’ And then she [the woman] was telling me how you have to be careful. She told me that apparently her brother used to practise it and it became a problem. It was almost like he was leaving his body and it was becoming an out-of-body experience. According to her, people who practise it, their souls never return to their body and it becomes something really dangerous. ‘You have to pray!’
The Nocturnal Brain Page 18