1. What is A Parasomnia?
A parasomnia is an abnormal behavior that happens during the sleep cycle that manifests with unwanted sensory, motor, or behavioral experiences.
2. What Are The 4 Types of Parasomnias?
According to the International Classification of Sleep Disorders-3, there are 3 main types of parasomnias :
- NREM-Related Parasomnias
- REM-Related Parasomnias
- Other Parasomnias
The normal sleep pattern includes the transition from wakefulness to NREM (Non-REM) sleep and then to REM (Rapid Eye Movement) Sleep and follows a repetition of a cycle that comprises 5 phases measured by electroencephalography (ECG) :
The NREM (Non-REM) sleep include 4 phases:
- Phase 1: light sleep phase characterized by slow eyes’ movement and muscle relaxation.
- Phase 2: this phase is characterized by the cessation of eyes’ movement and the slowdown of the brain waves such as the electrical pulses associated with wakefulness.
- Phase 3: beginning of deep sleep delta waves. At this stage, the delta waves are interrupted by faster and smaller waves.
- Phase 4: characterized uninterrupted delta waves leading to deep sleep.
Rapid Eye Movement (REM) or phase 5 is characterized by rapid eye movements, rise in heart and blood pressure, and dreaming.
2.1. What Are NREM-Related Parasomnias?
Non-REM-related parasomnias are abnormal behaviors that happen during the non-REM sleep phases and that manifest with undesirable sensory, motor, or behavioral experiences.
Non-REM-related parasomnias include confusional arousals, sleepwalking, sleep terrors, and sleep-related eating disorders.
2.1.1. What Are Confusional Arousals?
Confusional arousals or sleep drunkenness are characterized by partial awakenings during phase 3 of the sleep pattern that manifests with the individuals being disoriented, confused, having their eyes open, and without activity.
Confusional arousals can last minutes or a few hours with the individuals not remembering this event upon awakening after sleep. They are commonly found in children than adults.
- What Causes Confusional Arousals?
2.1.2. What Is Sleepwalking (Somnambulism)?
Sleepwalking or somnambulism is a partial awakening characterized by an ambulatory behavior such as walking around, walking naked, urinating, or playing a musical instrument, and without realizing it.
Sleepwalking also occurs during phase 3 of the sleep pattern and is frequently associated with sleep apnea and restless leg syndrome.
- What Causes Sleep Walking (Somnambulism)?
It can also be caused by intake of medications such as antidepressants (mirtazapine, amitriptyline, bupropion, or paroxetine), benzodiazepine receptor agonists, antipsychotics (quetiapine or olanzapine), antihypertensives (metoprolol, propranolol), montelukast, topiramate, or fluoroquinolones .
2.1.3. What Are Sleep Terrors?
Sleep terrors or night terrors are episodes of sudden fear accompanied by screaming, crying, sweating, and increased heartbeat and breathing. The episodes of sleep terrors can last from 3-5 minutes. Sleep terrors are common in children and disappear by late childhood.
- What Causes Sleep Terrors?
In adults, sleep terrors can be associated with sleep apnea and can be caused by mental health issues or intake of medications .
2.1.4. What Are Sleep-Related Eating Disorders?
Sleep-related eating disorders are partial awakenings in which individuals binge eat food or unhealthy food (uncooked food such as raw meat) without realizing it.
- What Causes Sleep-Related Eating Disorders?
Sleep-related eating disorders can be caused by narcolepsy, smoking cessation, encephalitis, substance abuse, autoimmune hepatitis, and certain medications such as sleep medications (e.g., zolpidem), antidepressants (e.g., mirtazapine), and anticholinergics .
2.1.5. What Is Sexsomnia?
Sexsomnia is characterized by abnormal sexual behavior such as sexual vocalizations, sexual assault, masturbation, sexual intercourse, or fondling the bed partners during stage 3 of sleep.
- What Causes Sexsomnia?
Sexsomnia can be caused by shift work and medications such as selective serotonin reuptake inhibitors (SSRI) .
2.2. What Are REM-Related Parasomnias?
REM-related parasomnias are abnormal behaviors that happen during the REM (Rapid Eye Movement) sleep phase.
REM-related parasomnias include REM sleep behavior disorder, recurrent isolated sleep paralysis, nightmare disorder, and Catathrenia.
2.2.1. What is REM Sleep Behavior Disorder?
REM sleep behavior disorder is an episode that manifests with motor activities that can be violent, such as kicking, jumping, punching, yelling.
- What Causes REM Sleep Behavior Disorder?
REM sleep behavior disorder can be caused by an abrupt alcohol withdrawal, an abrupt withdrawal of sedative-hypnotic medications, tricyclic antidepressants, cholinergic medications, selective serotonin reuptake inhibitors (SSRI), biperiden, and monoamine oxidase inhibitor (MAOI).
2.2.2. What Is Recurrent Isolated Sleep Paralysis?
Recurrent isolated sleep paralysis is characterized by the incapacity to move muscles upon awakening.
- What Causes Recurrent Isolated Sleep Paralysis?
Recurrent isolated sleep paralysis is caused by extended muscle inactivity associated with the REM sleep phase.
2.2.3. What Is Nightmare Disorder?
A nightmare disorder is characterized by recurrent frightening dreams that seem real resulting in sudden awakening. It is the most common adult parasomnia is a nightmare with a lifetime prevalence of 66.2%
- What Causes a Nightmare?
Nightmares can be caused by stressful events such as post-traumatic stress, or medications (e.g., beta-blockers) .
2.2.4. What Is Catathrenia?
Catathrenia is characterized by episodes of recurring groining during the REM phase of sleep.
- What Causes Catathrenia?
2.3. What Are Other Parasomnias
2.3.1. What Is Exploding Head Syndrome?
The exploding head syndrome is characterized by a loud or explosion sound in the head that happens during the wake-sleep transition or upon awakening .
2.3.2. What Are Sleep-Related Hallucinations?
Sleep-related hallucinations are episodes of visual, auditory, or tactile hallucinations that happen at the beginning of sleep (Hypnogogic hallucinations) or at awakening (Hypnopompic hallucinations).
2.3.3. What Is Sleep Enuresis (Sleep Bedwetting)?
Sleep enuresis or Sleep bedwetting is characterized by episodes of recurrent and involuntary urination during sleep due to the difficulty waking while with a full bladder.
2.3.4. What Is Sleep Talking?
Sleep talking is characterized by episodes of involuntary talking during the NREM and REM phases of sleep. Although benign, it can disturb the sleep of the partner.
3. How Do You Get Parasomnia?
They are several types of parasomnias that can be caused by mental health issues, physical conditions, medication intake (e.g., antidepressants), post-traumatic stress, sleep disorders, or neurological diseases.
However, some parasomnias are benign and are considered normal variants such as sleep talking.
4. Is Insomnia a Parasomnia?
Insomnia is not classified as parasomnia.
Insomnia is a common sleep disorder characterized by difficulty falling asleep, while parasomnia is an abnormal behavior that happens during sleep and that manifests with unwanted sensory, motor, or behavioral experiences.
5. Why Do I Shout in My Sleep?
Shouting or yelling during sleep may be due to a sleep terror or a REM sleep behavior disorder which are both parasomnias that have yelling as one of the manifestations. However, it is best to seek the advice of a specialist doctor.
6. What Is the difference Between a nightmare and a Night Terror?
A nightmare is characterized by recurrent frightening dreams that seem real resulting in sudden awakening, while a night terror (sleep terror) is an episode of sudden fear accompanied by screaming, crying, sweating, and increased heartbeat and breathing.
In addition, a nightmare is classified as a REM-related parasomnia, while a night terror is an NREM-related parasomnia .
Parasomnias can be distressful as they can disturb the sleep of partners or raise worries for the family.
Although not all parasomnias are serious, the treatment of more severe ones aims at dealing with the causes which can be associated with mental health issues, physical conditions, medication intake (e.g., antidepressants), post-traumatic stress, sleep disorders, or neurological diseases.