Parasomnia: A complex sleep disorder

What is the definition of Parasomnia?

The American Academy of Sleep Medicine in collaboration with other international sleep groups developed “The International Classification of Sleep Disorders (ICSD)” which classifies sleep disorders as either dyssomnias (disorders that produce insomnia or excessive sleepiness) or parasomnias (disorders that occur during sleep but do not produce insomnia or sleepiness).

The word “parasomnia” is derived from the Latin and translates as “around sleep”. A parasomnia is a group of sleep disorders in which you perform undesirable behaviors while you are asleep — but which do not cause you to be sleepy the next day.


Different Types of Parasomnia

The physical changes in the body that occur with parasomnias are unknown and may vary with the individual type of parasomnia. In some of the disorders, different parts of the brain may be inappropriately inactivated or activated. In addition, some of the disorders occur during REM sleep while others occur during non-REM sleep.

The category of parasomnias includes many disorders that interrupt or occur during sleep. The common ones are:

NREM Parasomnia

This type of parasomnia is characterized by occurrence of symptoms during stage 3 of NREM sleep or during slow wave sleep (SWS). The physiological systems including the autonomic nervous system, motor system and the cognitive process are activated and the brain exists between sleep and wake transitions.

Confusional Arousals

As the name indicates this parasomnia is characterized by the presence of confusion after waking up from sleep. Confusional arousal is more common in children than it is in adults. The child wakes up from sleep and is confused, often crying inconsolably and having thrashing movements in bed.

Sleep Walking (Somnambulism)

Sleep walking or somnambulism is characterized by walking or moving while asleep. The patient arises during the slow wave sleep stage and walks around in a state of lowered consciousness. Activities that are usually performed in a fully conscious state are often performed by sufferers of sleep walking.

While children are more prone in developing this sleep disorder, sleep walking can occur at any age. The activities performed during sleep walking can be either simple and harmless such as sitting up in bed, or complex and hazardous such as having sex or driving. There are instances of patients showing violent and homicidal behaviors during sleep walking. Since the patient is in a state of lowered consciousness it is often difficult for them to recall exactly what happened. This is often referred to as amnesia.

Sleep Terrors

Sleep Terrors are also known as night terrors and occur during the first two hours of sleep as opposed to nightmares that mainly happen right before waking up. Symptoms include sudden awakening (usually with a scream) with rapid heart rate and breathing and sweating. You will usually have no memory of the incident since sleep terrors are not caused by nightmares. There does seem to be a genetic component to this disorder since some research indicates that sleep terrors occur more commonly in some families. Sleep walking may also be connected to sleep terrors since people with this disorder may actually get out of bed during the episode. There is some research that also indicates that sleep terrors may be associated with certain forms of epilepsy.

Sleep Terrors (Night Terrors)

Sleep terror or night terror episodes usually appear in early childhood. The attack occurs after 1 to 2 hours of falling asleep and is characterized by violent screaming associated with frightened and fearful appearance of the child. There are often symptoms of increased heartbeat, rapid breathing and sweating present. There is no memory of the attack as the child is deep asleep. It is usually very difficult to console and soothe the child.


Nightmares differ from sleep terrors in that nightmares usually happen right before waking up and the victim usually has a vivid memory of the dream. Nightmares are usually caused by anxiety or stress and typically include symptoms of fear or distress.

Sleepwalking and Sleep talking

Sleepwalking and Sleep talking are sleep disorders that can occur when you are overly tired, stressed or sleep deprived. You may not even be aware of these syndromes unless you wake up in an unusual place or unless a bed partner tells you about the activities. In these syndromes, you walk, talk or do other activities while remaining fast asleep. If you use alcohol or sedatives to help you sleep, you may be at higher risk for these disorders. A sleepwalker will wake up confused and without any memory of doing anything while sleeping.

Sleep related sinus arrest

Sleep related sinus arrest is a potentially serious condition in which your heart stops for brief periods of time during REM sleep. This condition can only be diagnosed in a sleep lab or through the use of an EKG monitor during sleep. When the condition is detected, a pacemaker will be inserted to control the heart’s rhythm.

Sudden Unexpected Nocturnal Death

Sudden unexpected nocturnal death is a death that may occur in a young healthy person during sleep. This condition seems to occur most commonly in males of Southeast Asian heritage and can be associated with sleep terrors and an unexplained choking incident during sleep.

Sleep related behavior disorder

Sleep related behavior disorder is a condition in which the muscle paralysis normally seen in REM sleep is not there and the person begins to act out his dreams. This may include jumping out of bed, biting, pulling hair, punching and kicking. For an unwitting bed partner, this disorder may result in injuries.

Sleep Paralysis (SP)

On the other side of the coin is sleep paralysis in which the brain does not turn on your body’s normal muscle function as you begin to wake up. In normal sleep, the brain deactivates your body’s muscle function so you cannot act out your dreams. As you awaken, your muscles are reactivated and you can move. In SP, you wake up before your muscles have been reactivated and you feel as if you are tied down in bed and unable to move. The paralysis typically only lasts for a few seconds to a few minutes, but it is common to feel extreme panic and shortness of breath. Many victims also report vivid hallucinations called hypnagogic hallucinations during an episode of SP.


Enuresis is bedwetting in a person over 5 years old. In children younger than 5, accidents at night are frequent and not cause for alarm. If your child is still wetting the bed after the age of five, s/he should be evaluated by your doctor. Common causes of enuresis include an allergy, breathing problem, or seizure disorder.


Worn Teeth Due to Teeth Grinding

Bruxism is the grinding of teeth at night. It is one of the most common parasomnias. This syndrome is typically not a problem but may cause headaches or jaw pain. If left untreated it could cause permanent damage to the teeth and eventually lead to tooth loss.


Snoring can be diagnosed when you snore without any other signs or symptoms of a sleep related breathing disorder. If you snore and sleep by yourself, you may not be aware of the disorder; if you sleep with someone else, your bed partner has probably complained about your snoring!

Sleep Apnea

Sleep apnea occurs when you have periods of time during sleep when you stop breathing. This is an unusual syndrome in children and is typically caused by a very small airway. For a child with this problem, your doctor may order an apnea monitor to use until the child outgrows the problem.

Sudden Infant Death Syndrome (SIDS)

Sudden Infant Death Syndrome (SIDS) is defined as the unexpected death of an infant (less than 3 months old) without an apparent medical cause. This syndrome is in the news every time an infant dies without explanation.

REM Parasomnia

This parasomnia occurs during the REM cycle of sleep, and is also known as REM Sleep Behavioral Disorder (RBD). In this type of disorder muscle relaxation doesn’t occur, resulting in a tiresome sleep. Parasomnia RBD is more common in males who are more than 50 years of age. The patient suffering from it shouts and screams in their dreams with violent motor activity resulting in injury in the form of bruises and lacerations to themselves or partner.

Acute RBD is usually caused as a side effect to antidepressants. The cause of chronic RBD is usually unknown. However, there is an increased incidence of chronic RBD occurring with neurological disorders such as Parkinson’s disease and dementia. RBD is more common in individuals suffering from narcolepsy.

Restless Legs Syndrome (RLS) and Periodic Limb Movements Disorder (PLMD)

These are characterized by the constant urge to move the legs to get relief from unpleasant sensations that occur in the lower part of legs.


Cataplexy is characterized by sudden and temporary muscle atonia or loss of muscle tone often caused due to strong emotions such as anger, fear, laughter and surprise. Cataplexy commonly affects people suffering from narcolepsy but can also occur as a symptom of SSRI discontinuation. The symptoms of cataplexy are muscular weakness, slurred speech and impaired vision.

Exploding Head Syndrome

Exploding head syndrome is a type of parasomnia that is characterized by the occurrence of a loud noise such as that of an explosion, gunshot or a scream originating from the head of the patient. The noise is usually experienced an hour or two after falling asleep and is often accompanied by a perceptions of light flashes. The attack is followed by symptoms of anxiety, fear and rapid heart rate.


Causes of Parasomnia

Family history tends to be a causing factor to some parasomnias like confusional arousal, sleep walking, and night terrors. Various other triggers including fatigue, sleep deprivation and certain medicines. In some patients the episodes are also triggered by other medical illnesses like fever, sleep apnea, depression, epilepsy/seizure and heartburn.

Bruxism could be triggered by trauma such as a car accident, emotional and physical stress, medical ailment such as anxiety or an allergic reaction.

Alcohol intake and stimulants also act as triggers for many of the parasomnias.

Acute RBD is usually triggered as a side effect to antidepressants.

Chronic RBD may occur in association with other neurological diseases such as Parkinson’s and dementia. RBC is also more common in patients suffering from narcolepsy.

Nightmare disorder may be caused as a result of a stressful life event such as the death of a loved one. It is also associated with other psychiatric disorders like post traumatic stress disorder (PTSD), depression etc. Nightmares may also occur as a side effect to certain medications such as antidepressants, levodopa and some antihypertensive drugs.


Diagnosis of Parasomnia

Because some parasomnias are more dangerous than others early detection and treatment is important. This is because they may lead to serious health problems including bodily injuries, emotional distress, anxiety, guilt etc.

A professional diagnosis of the different types of Parasomnias is made by conducting a detailed clinical interview and polysomnography test.

Detailed Clinical Interview

Patient’s detailed medical and psychiatric history is recorded along with family history, alcohol and drug history and sexual, physical or emotional abuse history. A thorough physical and neurological examination is also conducted as part the clinical interview.

Polysomnography (Sleep test)

A polysomnography test is normally conducted at a sleep study center. The patient stays there overnight whilst a specialist checks their parameters during all sleep stages. Some of the parameters checked are:

  • Electroencephalogram (EEG). It is recorded to study the electrical activity of the brain.
  • Electrocardiogram (ECG). It is recorded to study the electrical activity of the heart.
  • Electrical activity of the muscles is also checked.


Treatment of Parasomnias

The good news about the parasomnias is that most of them are not harmful. The exceptions to this are sudden unexpected nocturnal death and sudden infant death syndromes. Both of these syndromes result in death — but prevention efforts do not seem to be effective.

For the remainder of the parasomnia syndromes, when the episodes happen frequently or are very disruptive to your sleep, you should seek help from your healthcare provide. The parasomnia syndromes can be aggravated by medical and psychiatric conditions so an extensive physical and mental status exam should be done to rule out any treatable conditions that may be causing the sleep disorder. If an underlying cause is discovered, you will probably be referred to an appropriate specialist for treatment.


Treatment of the parasomnias is aimed at decreasing the frequency or intensity of the sleep events. Your healthcare provider may prescribe a sleeping medication or antidepressant for a short period of time.

Drugs belonging to the class of benzodiazepines and anticonvulsants are used to treat various parasomnia symptoms. The goal of a drug treatment is to inhibit arousal and suppress the REM stage of sleep.

Over the counter sleep aids such as melatonin, diphenhydramine or valerian root may be effective in promoting sound sleep and preventing some of the syndromes. Some prescription medicine like diazepam (valium), alprazolam (xanax), clonazepam (klonopin), tegretol and neurontin can be used as well.

Behavioral Therapies

Monitoring heart rate via Biofeedback

Hypnosis, biofeedback and stress reduction have been shown to be effective in treating parasomnias that are NOT caused by a physical problem. One study found that about 40% of sufferers showed improvement after hypnosis — even 5 years after treatment! However, as with most disorders, the most effective treatment is prevention.

Prevention of Parasomnias

What can you do to prevent parasomnias? Lack of sleep may increase your risk for many of the parasomnias so it is critical to get enough sleep EVERY night.

To get adequate sleep, it is important to make sure you NOT nap during the day and get enough physical exercise so that you are tired at night. Don’t exercise right before bedtime since it may increase your adrenaline keeping you awake. Don’t use caffeine, alcohol and nicotine before bedtime since all of these can cause or increase the parasomnias. Large meals can cause heartburn and reflux that will disrupt your sleep. These disruptions will increase your risk for the parasomnias.

Make your bedroom conducive to sleep. Use blackout curtains and fans to keep your bedroom cool, dark and quiet. Take the television out of your bedroom using your bedroom for sleep and sex only. A warm bath and gentle massage may help to reduce the stress that may be a risk factor for some of the parasomnia disorders.


Parasomnia Statistics

How common are the different parasomnias? That’s hard to say since many of these disorders may never be reported. Estimates of the incidence of parasomnias as a group range from about 4% to 67%.

For sleep walking, some research reports at least 22% of all people may have at least one sleep walking incident. As many as 30% of children may experience at least one occurrence of sleep walking.

The incidence of sleep talking may be as high as 66%. Children with respiratory problems are twice as likely as healthy children to experience sleep walking, sleep talking and enuresis. Children with one of the parasomnia disorders are also more likely to have other sleep disorders.

Sleep terrors may occur in over 10% of the population; however, with a prevalence of 40% in preschoolers, children tend to have this sleep disorder much more often than adults. Boys are more likely than girls to experience sleep terrors.

Nightmares, on the other hand, are experienced by 66% of the population over the course of a lifetime; if you are a woman, you are more likely to report nightmares. In children aged 3-5 years, 10-50% may have nightmares.

Sleep related behavior disorders are relatively rare and are typically not seen before you reach the age of 60 to 70; in addition, this disorder seems to be more common in some families than others so there may be a genetic cause.

In some studies, 12% of those surveyed reported having five or more parasomnias.

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