Sleep paralysis linked to stress and PTSD

Model Kendal Jenner has spoken out about the terrifying effects of her sleep paralysis

The causes of sleep paralysis have not been fully understood – until now. 

Researchers now believe the distressing condition is brought on by a much wider number of factors than previously thought.

Experts have identified stress and specifically post-traumatic stress disorder (PTSD) as key reasons. 

They also say substance use, genetics, physical illness, personality, sleep disorders, anxiety, intelligence and psychiatric illnesses also have an effect. 

These were the findings of a review of 42 studies published in scientific journals on the subject.

Sleep paralysis – suffered by model and reality TV star Kendal Jenner, 22, – is a temporary inability to move or speak that occurs when you’re waking up or falling asleep. 

It happens when parts of rapid eye movement (REM) sleep – a stage of sleep when the brain is very active and dreams often occur – happens while you’re awake. The body is unable to move, apart from the eyes and muscles used in breathing. 

The accepted causes are currently: Not getting enough sleep (sleep deprivation or insomnia), irregular sleeping patterns (for example, because of shift work or jet lag), narcolepsy, a family history of sleep paralysis and sleeping on your back, according to NHS Choices.

Researchers believe sleep – suffered by Kendal Jenner – is brought on by stress and post-traumatic stress disorder (PTSD), among a number of factors (stock image)

Researchers believe sleep – suffered by Kendal Jenner – is brought on by stress and post-traumatic stress disorder (PTSD), among a number of factors (stock image)


Vogue cover girl Kendal Jenner revealed the terrifying effects of her sleep paralysis to her sister Kim.

She discussed the problem last year on an episode of Keeping Up With the Kardashians.

‘It’s like you’re asleep, and then in the middle of the night… basically, your mind wakes up but your body is still asleep,’ she said.

‘You wake up, and nothing can move.

‘It’s the scariest thing in the entire world, you’re freaking out because all you want to do is be able to move, so you’re laying there, trying to move, trying to relax. 

It’s has not been not clear why REM sleep can sometimes occur while you’re awake – but experts have now shed some light which could lead to better interventions.  

‘Sleep paralysis is a relatively common but under-researched phenomenon,’ wrote experts from Goldsmiths University of London in the journal Sleep Medicine Reviews.

‘Sleep paralysis appears to be particularly prevalent in post-traumatic stress disorder, and to a less degree, panic disorder.’ 

Between 8 per cent and 50 per cent of people experience sleep paralysis at some time, and about 5 per cent of people have regular episodes, according to the Handbook of Sleep Medicine. 

What do we already know about sleep paralysis?  

NHS Choices says that in many cases, the experience is a one-off or very occasional event that occurs in someone who is otherwise healthy.

It explained that it is not harmful and should pass in a few seconds or minutes, but can be very frightening.

Many people have sleep paralysis once or twice in their life, while others experience it a few times a month or more regularly.

It affects people of all ages and is most common in teenagers and young adults.

But for some people suffering severe cases, a course of antidepressant medication may be prescribed. 

The latest research 


The main symptom is being completely aware of your surroundings but temporarily being unable to move or talk.

This usually occurs as you’re waking up, but can happen when falling asleep.

During an episode you may:

  • Find it difficult to take deep breaths, as if your chest is being crushed 
  • Be able to move your eyes – some people can also open their eyes but others find they can’t
  • Have a sensation that there’s someone or something in the room with you (hallucination)
  • Feel very frightened

The length of an episode can vary from a few seconds to several minutes.

You’ll be able to move and speak as normal afterwards, although you may feel unsettled and anxious about going to sleep again.

Source: NHS Choices 

In the review, the experts compared the frequency of sleep paralysis episodes with numerous variables, including income, age, sex, diet, ethnicity, caffeine intake, genetics, stress levels and IQ.

Many of these factors showed negligible or inconclusive links, said the authors. However, it was clear that poor sleep quality was connected to sleep paralysis attacks.

Generally they found that the less restful an individual’s sleep was, the more likely they were to experience sleep paralysis. 

Several studies discovered that people who slept for less than 6 hours or more than 9 hours at a time were most likely to have episodes upon waking.

Napping was also linked to a raised risk of sleep paralysis.

Patients who had been diagnosed with PTSD showed significantly higher rates of sleep paralysis across many studies.

To a lesser extent, people who were prone to general stress and social anxiety were also more likely to experience episodes.

The authors said further research was needed to investigate what comes first: sleep problems or anxiety.


Sleep paralysis often gets better over time, but improving your sleeping habits and sleeping environment may help.

It can help to:

  • Get a good night’s sleep – most adults need six to eight hours of good quality sleep a night
  • Go to bed at roughly the same time each night and get up at the same time each morning
  • Create a sleeping environment that’s comfortable, quiet, dark and not too hot or cold
  • Avoid eating big meals, smoking, or drinking alcohol or caffeine shortly before going to bed
  • Get regular exercise (but not within four hours of going to bed)

Read more about how to improve your sleep habits.

If your sleep paralysis is particularly severe, a specialist doctor may suggest taking a course of antidepressant medication, such as clomipramine.

These work by altering REM sleep and are typically prescribed at lower doses than when used for depression.

Source: NHS Choices