How science explains ‘sleep paralysis’ – 04/26/2023 – Equilibrium

It first happened when I was a teenager. It was early in the morning, a few hours before I got up to go to school.

I woke up and tried to turn over in bed, but my body wouldn’t let me.

I couldn’t move. He was paralyzed from head to toe.

My brain was conscious, but my muscles were still asleep.

The room felt hot and confining, as if the walls were closing in.

I panicked until, about 15 seconds later, I was able to move.

Only later did I discover the name of what had happened to me: sleep paralysis.

It’s a surprisingly common nocturnal condition in which part of your brain wakes up while your body remains temporarily paralyzed.

After that first frightening episode, the paralysis became frequent – one episode every two or three nights.

The more it happened, the less frightening it became, until it was little more than an inconvenience.

But sleep paralysis can be something much more serious. And for some people, it is accompanied by terrible hallucinations.

I spoke with a person affected by the condition, who asked to be identified by first name only. Victoria is 24 years old and remembers what happened to her one night when she was just 18.

“I woke up and I couldn’t move,” she says. “I saw this gremlin-like figure hiding behind my curtain. It jumped on my chest. I thought I had entered another dimension. And the scary thing was, I couldn’t scream. It was all so vivid, so real.”

Other people hallucinate demons, ghosts, aliens, menacing intruders, and even dead relatives.

They see parts of their own bodies floating in the air or cloned copies of themselves standing beside the bed. Some see angels and later believe they had a religious experience.

Researchers believe these hallucinations may have fueled the belief in witches in early modern Europe, and perhaps even explain some current reports of alien abductions.

Scientists believe that sleep paralysis has probably been around since the dawn of humans.

There are several detailed descriptions of episodes throughout the history of literature. Mary Shelley, for example, was apparently inspired by a painting illustrating an episode of sleep paralysis to write a scene in the book. frankenstein.

But sleep paralysis has only recently begun to be studied.

“It was an ignored phenomenon… but, in the last 10 years, the interest has been increasing”, says the sleep researcher Baland Jalal, from Harvard University, in the United States.

In 2020, Jalal conducted what may have been the first clinical trial on different forms of sleep paralysis treatment.

Jalal is one of the few sleep scientists who are investing time and energy into researching this condition.

They hope to build a more detailed picture of its causes and effects – and discover what the condition can tell us about the mysteries of the human brain as a whole.

Until recently, there was little consensus about the experience of sleep paralysis. Studies were sporadic and there was little consistency between methods.

Until, in 2011, clinical psychologist Brian Sharpless conducted the most comprehensive analysis ever conducted on the incidence of the condition. At the time, he was working at Pennsylvania State University and is currently a visiting professor at St. Mary’s College of Maryland, both in the United States.

The psychologist is also one of the authors of the book Sleep Paralysis: Historical, Psychological and Medical Perspectives (Sleep Paralysis: Historical, Psychological and Medical Perspectives, in free translation).

Their analysis included data from 35 studies conducted over five decades. Collectively, they involved more than 36,000 volunteers.

Sharpless concluded that sleep paralysis is more common than previously thought.

Almost 8% of adults said they had had the experience at some point in their lives. This rate is much higher among university students (28%) and psychiatric patients (32%).

“It’s really not that uncommon,” says Sharpless.

Explanation and treatment

After experiencing the condition, some people look to supernatural or even paranormal explanations. But in fact, Jalal explains that the cause is much simpler.

At night, our body goes through four stages of sleep. The last stage is called rapid eye movement (REM). It is at this stage that we dream.

During REM sleep, the brain paralyzes muscles, presumably to prevent you from physically acting out your dreams and injuring yourself. But sometimes (scientists still don’t know exactly why), the sensory part of the brain comes out of REM sleep prematurely.

With that, you wake up. But the lower part of the brain is still in REM, Jalal explains, and it keeps sending out neurotransmitters to paralyze your muscles.

“The sensory part of the brain becomes active,” according to Jalal. “You’re waking up mentally and sensorially – but physically you’re still paralyzed.”

When I was in my early 20s, I suffered from sleep paralysis every two or three nights, but the impact on my life, even then, was small.

It was just an interesting story to tell family and friends. And in this particular my experience was common.

“For most people, it’s a quirky part of their lives,” says Colin Espie, professor of sleep medicine at the University of Oxford in the UK.

“It’s a bit like sleepwalking,” he says. “Most sleepwalkers never see a doctor. It’s a familiar curiosity, a topic of conversation.”

But for an unfortunate minority, the condition is more challenging. Sharpless’ research concluded that 15% to 44% of people suffering from sleep paralysis experience “clinically significant stress” due to the condition.

Problems often arise as a result of how we react to sleep paralysis rather than the condition itself. Patients spend their days obsessing over when the next episode might strike.

“It can be anxiety-provoking at the beginning and end of the night,” explains Espie. “You grow a web of worry around it. Its worst expression is becoming a sort of panic attack.”

In the most serious cases, sleep paralysis can be a sign of latent narcolepsy – a more serious sleep condition in which the brain is unable to regulate sleep and waking patterns, causing the person to fall asleep at inappropriate times.

Doctors say that paralysis occurs more often when a person sleeps little, which fragments the sleep architecture. Some patients also tend to suffer more when they sleep on their backs, although the explanation for this phenomenon is unknown.

The most common sleep paralysis treatment is educational. Patients simply learn the science behind the condition and are reassured that there is no danger.

Sometimes some form of meditation can be used. The goal is to reduce patients’ anxiety at bedtime and train them to remain calm when sleep paralysis strikes.

In more serious cases, medication may be considered, including selective serotonin reuptake inhibitors (SSRIs), commonly used to treat depression but which have the side effect of suppressing REM sleep.

‘Storytelling Machine’

The most dramatic and memorable episodes of sleep paralysis are often accompanied by vivid hallucinations. Usually these night visions are frightening, but scientists also believe they can tell us fascinating stories about the human brain.

When we go into sleep paralysis, the brain’s motor cortex starts sending signals to the body, telling it to move. But the muscles are paralyzed, so the brain does not receive feedback signals.

“There is an incongruity… the individual is broken, decomposed”, says Jalal.

As a result, the brain “fills in the gap” and creates its own explanation why the muscles cannot move. This is why so many hallucinations include a creature sitting on the chest or holding the person’s body.

This process reinforces the idea common among evolutionary scientists that the human brain is a “storytelling machine”.

We struggle to come to terms with the fact that so much of the world is random, and our brains concoct dramatic narratives in an effort to find meaning in the mundane.

Christopher French, head of the anomalistic psychology research unit at Goldsmiths University in London, has spent more than a decade talking to people around the world who have experienced such hallucinations and recording what they say.

“There are common themes, but there are also a lot of idiosyncrasies, a lot of variability,” says French.

Some hallucinations are difficult to explain and even simply bizarre.

Over the years, French has recorded visions of a sinister-looking black cat and a man being strangled by plants. But other hallucinations are much more common and seem to be heavily influenced by local culture.

In Newfoundland, Canada, it is common to see an “old hag” sitting on a chest. Mexicans, on the other hand, report a “dead man” lying on his chest, and in Saint Lucia, in the Caribbean, people speak of kokma – the souls of unbaptized children – strangling them in their sleep.

Turks describe the karabasan, a mysterious and ghostly creature, while Italians often hallucinate witches.

All this strengthens the idea that human beings are predominantly social animals and strongly influenced by culture and expectations.

In fact, in a series of studies, Baland Jalal compared the symptoms of sleep paralysis in Denmark and Egypt, among volunteers with similar age and gender distribution. He found a cultural abyss in the forms of manifestation of sleep paralysis.

Egyptians suffered sleep paralysis much more often than Danes (44% versus 25%) and were more likely to come up with supernatural explanations. The Egyptian volunteers who believed in ghosts and demons also spent more time paralyzed in each episode.

Jalal’s theory is that fear of the supernatural increases people’s fear of sleep paralysis. And this anxiety makes the most common phenomenon – a demonstration of the intimate relationship between our body and our mind.

“When you have stress and anxiety, your sleep architecture will become more fragmented, so you’re more likely to experience sleep paralysis,” he says.

“Say your grandmother says, ‘the creature looks like this, it comes at night and attacks you,'” he continues. “And because of that fear, [você fica] hyper-aroused, your brain’s fear centers are hyper-alert. And lo and behold, during REM sleep, [você] feels, ‘oh, something is wrong, I can’t move, the creature is here’.”

“It seems that culture really can create this surprising effect,” concludes Jalal.

read the original version of this report (in English) in the website BBC Future

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