Complete Guide to Parasomnia


Sleep and sleeping disorders are some of the most mysterious things in science. Considering it’s a practice we all undertake, there’s a surprising amount we don’t understand about sleeping.

Sleep disorders can be something as benign as jet lag, or as terrifying as sleep paralysis. However, perhaps the most complex and concerning sleep disorders of all… are parasomnias.

parasomnia definition

Parasomnia Definition

What is parasomnia? Parasomnias fall under the more general category of sleeping disorders, like insomnia, narcolepsy, and sleep apnea.

Unlike other types of sleeping disorders, parasomnias are characterized by ‘complex, semi-purposeful, and goal-directed behaviors.’

The word parasomnia takes its name from the word “para,” which means abnormal or incorrect, and “somnia,” which means sleep.

This study defines parasomnias as “undesirable behavioral, physiological, or experiential events that accompany sleep.” In other words, they are abnormal behaviors that occur during sleep.

Common parasomnia symptoms include feeling groggy during the day (due to a lack of sleep), disorientation, and fear upon waking up. However, it can be hard to self-diagnose parasomnia. As such, diagnosis often starts with bed partners complaining about abnormal behavior during the night.

Why Does Parasomnia Occur?

To understand why parasomnias occur, we have to first look at how sleep happens. Sleep consists of two stages: REM (which stands for rapid eye movement) and NREM (which stands for non-rapid eye movement.) These two states alternate as you sleep.

Sleep occurs in cycles, with a few stages of NREM, one deeper than the last. Then, after about 90 minutes of sleep, the brain enters the REM phase.

This cycle then repeats, with REM stages growing longer and longer, with the longest REM periods in the last third portion of sleep.

Parasomnias occur when you are aroused from sleep. The type of parasomnia that happens will depend on the type of sleep state that it occurs in: the REM state or the NREM state.

REM and NREM parasomnias

Because of the nature of sleep cycles, the type of parasomnia you experience will also coincide with how long you have been asleep.

For example, you are most likely to experience REM parasomnias later on in your sleep, because the REM state is prolonged during this time.

Those who suffer from REM parasomnias are most likely to remember their experience and will be alert when awake. Commonly, people who suffer from REM parasomnias are described to be fully asleep, but with motor functions.

On the other hand, those who experience NREM parasomnias will most likely be confused when awoken, and will not remember their experience. Those who suffer from NREM parasomnias are commonly described as half-awake and half-asleep.


Parasomnia Types

Parasomnias can be categorized into two general categories, depending on when they occur.

The first type is the REM parasomnias. As its name implies, these parasomnias occur during the REM phase. The second type is the NREM parasomnias, which occur during the NREM sleep phases.

NREM Parasomnias

  1. Confusional Arousal

Have you ever been woken up abruptly from sleep, and had to take some time to remember where you are? This is a classic case of confusional arousal.

As its name implies, confusional arousal is characterized by confusion and slowed thinking, not knowing where and when you are, and responding inappropriately to stimulus, like responding too loudly to a question.

  1. Sleep Terrors

Also known as night terrors, sleep terrors are episodes where a person sits up abruptly in bed with a frightened expression and screams.

Any attempt to console the person won’t work, and they will look fully awake. This can last from around 30 seconds to three minutes and then the person often goes back to sleep.

People who experience sleep terrors often don’t remember this attack, although there have been reports of people remembering a single image and having a difficult time breathing.

  1. Sleepwalking

Also known as somnambulism, sleepwalking is a form of parasomnia that is familiar to most of us.

Sleepwalking doesn’t just involve walking; people with somnambulism may sit up with a blank stare or move with automated gestures (like picking at clothes).

They will be difficult to wake, will appear clumsy, and are likely to hurt themselves during the episode, through bumping into furniture or falling down stairs.

Sleepwalking often ends with the person going back to sleep.

  1. Sleep-Related Eating Disorder

Sleep-related eating disorder (or SRED) is a combination of parasomnia and binge-eating. People with SRED will compulsively consume food and will eat foods they usually would not.

Commonly, those with SRED will consume high-calorie foods and will avoid vegetables and fruits. There have also been cases of people eating dog food, uncooked meat, and detergents.

  1. Sexsomnia

Sexsomnia is also known as sleep sex. It is still unsure whether sexsomnia is a separate type of parasomnia or a variant of sleepwalking.

Sexsomnia is characterized by ‘complex sexual behaviors’ during sleep.

  1. Exploding Head Syndrome

Exploding Head Syndrome is characterized by suddenly hearing a sound so loud that it may feel like your head is exploding.

This sound can feel as though it comes from inside a person’s head and can include loud noises such as slamming doors, screaming, gun shots, or a bomb going off.

The source of the sound is entirely due to the parasomnia, although the cause for this parasomnia is still completely unknown.

parasomnia types

REM Parasomnias

  1. REM-Sleep Behavior Disorder

One of the more common types of REM parasomnias, REM-sleep behavior disorder (or RBD) is characterized by a person acting out their dreams.

The dreams that are enacted often become more threatening. Commonly, RBD often includes jerking, kicking, talking, and shouting.

In very small cases (about 0.5%) people who suffer from RBD may exhibit violent behaviors and put their bed partner in danger via actions like choking.

RBD can be a serious disorder, affecting both the individual and their bed partners. It can lead to fractured bones, lacerations, and sprains. People who wake up from an episode of RBD will remember emotions of fear.

  1. Nightmares

Nightmares are frightening or disturbing dreams that often awake the sleeper. Nightmares typically become more threatening and distressing as the dream progresses.

Other than disturbing images, nightmares can also include feelings of danger and anxiety; being chased or attacked is a common theme in nightmares.

Nightmares are similar to night terrors, although they do not include disorientation. Nightmares are also easy to recall and can be conveyed without too much difficulty when the person wakes.

  1. Hallucinations

Hallucinations in sleep disorders can be categorized into either hypnogogic hallucinations, which occur during the onset of sleep, or hypnopompic hallucinations, which happen when the person wakes.

Both types produce vivid experiences, most commonly visual. However, hallucinations can also be auditory, tactile, or cenesthopathic (or abnormal sensations).

Examples of cenesthopathic sensations include feeling that body parts have been switched around, or out of body experiences (the feeling that you are floating in the air and can see your body from the outside).

Hallucinations aren’t necessarily frightening in themselves; they can be pleasing or perhaps even benign.

Hallucinations often go away on their own, especially once people realize they are not real. It can sometimes end with one or several body jerks.

This video has more information on parasomnia.

Who is at Risk for Parasomnias?

Parasomnias are familiar to us, some types more common than others.

It has been reported that up to 10% of Americans suffer from parasomnias at least once in their life. But what puts you at greater risk than others?

Here are some factors that may raise your chances of experiencing parasomnias.


Parasomnias can occur at any age, but they are more common in children. They have a greater risk of experiencing parasomnias because of their rapidly developing brains.

Thankfully, parasomnias in children are often harmless, and those who experience it commonly don’t remember it in the morning. Parasomnias in children also tend to disappear as the child matures.


Parasomnias have been recorded to run in families, which implies that your genes may put you at a greater risk.

Those who suffer from parasomnia because of their genetics may benefit from visiting a sleep specialist.


Medications, like anti-depressants and beta-blockers, have been known to affect sleeping patterns. Those who are on these types of medications are at greater risk of experiencing parasomnias.

If your medication is a cause for regular sleep disruptions, it may be necessary to have your doctor change your prescription. Otherwise, lessen stress during the day and try to maintain quality sleep hygiene.

How to Prevent Parasomnias

The severity of parasomnia differs from one person to the next. Mild cases, like the occasional nightmare, often go away with better sleep.

Some ways to improve sleep include:

parasomnia symptoms

Improving Your Bedroom

Your bedroom should be as dark as possible, and with a comfortable amount of noise.

It should also be just the right temperature.

Create a Regular Sleep Schedule

It’s wise to get at least eight hours of sleep at night, but what’s more important is to have a regular sleep schedule. Try to go to sleep and wake up at the same time.

Even if you are pulling a late night, try waking up when you usually do and take a nap during the day.

Likewise, if you have to wake up early, go to sleep the same time at night anyway, and make up for the deficit with naps during the day.

Create a Nighttime Routine

Creating a routine that eases you into a relaxed, sleepy state is a great way to ensure a good night’s rest.

A routine could be something as easy as reading a book a few minutes before bed, or something more complicated that involves a shower, a cup of tea, and some yoga.

What’s important is that you avoid bright screens, like that of your phone or computer an hour before bed. (If you really have to look at screens, install a blue light filter.)

When to Go to the Doctor

Parasomnias are often harmless. Most times, the people who experience them don’t even remember it.

They also tend to be rare occurrences. But when do you seek treatment?

When You or Your Bed Partner Are at Risk of Injury

Often, parasomnias don’t just affect the person with parasomnia, but their bed partner as well. Bed partners who try to wake people with parasomnias can be met with hostility, which can lead to injury.

Barring that, bed partners can also experience stress over the situation or, at the very least, have their own sleep be disrupted.

When You or Your Partner Have Lowered Sleep Quality

Putting you or your partner at risk doesn’t necessarily mean a threat of violence or physical danger. Even poor quality sleep can be detrimental to you and your bed partner’s health.

If either of you experiences disruptions in your regular sleep, treat your parasomnia as an illness that needs treatment.


Increased Frequency and Severity

Parasomnias often go away on their own. However, if they begin to occur more often, with more serious episodes, it may be time to seek treatment.

Parasomnia Treatment

The treatment for parasomnia depends on the type you’re suffering from. However, the process will always begin with a diagnosis.

Bed partners are imperative at this stage, especially for patients whose parasomnia includes retrograde amnesia – or, in other words, they don’t remember it.

Your doctor will also look at your medical records, family history, and may ask about your sleeping patterns. Your stress levels will also be taken into consideration.

Substances that can affect sleep, such as alcohol and medication, will be evaluated. You may be asked to undergo a polysomnography (or a sleep test) which will track your heart, muscles, brain, and eye movements while you sleep.

This will help pinpoint what type of parasomnia you are suffering from. Your doctor may also recommend medication to give you a better sleep.

This video goes into more details about parasomnia.


Hopefully, this guide has answered all the questions you have about parasomnias.

Parasomnias can be terrifying, but they can also be easily treated. With the right medical care and enough rest, you’ll soon be sleeping like a baby once again.

Do you have experience with parasomnia? Which ones?


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