What is narcolepsy? Causes, symptoms and complications of sleep disorders

What is narcolepsy? Causes, symptoms and complications of sleep disorders
Photo source: Getty images

A sleep disorder called narcolepsy is a serious problem that causes a variety of problems. Why does it arise and what are the impacts on human life?


Narcolepsy is a sleep disorder and is a chronic neurological disorder. Thus, a disease of the nervous system, which is characterized by the inability of the brain to regulate the proper cycle of sleep and wakefulness.

The consequences are manifested mainly during the day, with extreme drowsiness. A person suddenly falls asleep, and it is not possible to suppress this condition by will.

The danger of this disease is that the phases of sudden sleep during the day come without any warning, and thus significantly affect the lifestyle of the affected person.

Narcolepsy is a disease that affects the nervous system.It is referred to by several names, such as DMS,which is an abbreviation of Daniel Merrick's Syndrome,but also as excessive daytime sleepiness, ie EVS.EDS stands for Excessive Daytime Sleepiness.

The disease affects the central nervous system, specifically the brain control center for the process of sleeping as well as waking up. As a result of this disability, sudden and uncontrollable bouts of sleep occur during the day. However, these seizures cannot be controlled by will.

Narcotic seizures occur without warning and during any activity. at home, in the store, while walking, shopping or talking, but also at work. And thus they significantly and significantly disrupt the quality of human life.  

Narcolepsy is not a common disease and affects an average of one to two people in 1,000. It manifests most often during adolescence with a peak between the ages of 35 and 40. In old age, it is subdued.

Heredity contributes to its origin, albeit only partially. It is also more prone to the disease due to the presence of certain genes. Narcolepsy is also problematic in that this sleep is not a full-fledged sleep, but the person is partially up. At the same time, he may suffer from various hallucinations and delusions.

Narcolepsy is further divided into:

  • narcolepsy with cataplexy, where, cataplexy is a sudden loss of muscle tone, i.e. tension
  • narcolepsy without cataplexy
  • secondary narcolepsy

What is sleep?

Woman sleeping in bed.
Alternation of non-REM and REM phases during sleep. Photo source: Getty images

Sleep is a condition where the function of the central nervous system is impaired. It resembles a state of unconsciousness, but is assessed as an altered state and not a perceptual disorder. It is a regular state of rest, which is important for the regeneration of the body. Lack of sleep can be the result of health problems.

Sleep is divided into two phases. This is the NREM phase, otherwise non-REM, also referred to as orthodox, synchronized sleep. The second phase is REM, or paradoxical sleep. These two phases alternate with each other. Non-REM comes from the English abbreviation non-rapid eye movement, ie without rapid eye movements. REM is an abbreviation of rapid eye movement.

During the night, the non-REM and REM phases alternate. And, synchronized sleep has 4 stages. The REM period occupies approximately 25% of the total sleep time. During the first phase of NREM, the person is the easiest to wake up and the deepest is sleep during the 4th period. Dreams are dreamed in REM. 

The non-REM phase changes to REM after approximately 90 minutes. Awakening usually occurs in the REM part.

Sleep changes with age. At the same time, in depth, its depth and need change. It is of lower quality, more frequent awakenings and the occurrence of the deepest parts of the non-REM phase is reduced.


The exact cause of narcolepsy is unknown. Narcolepsy is not a psychiatric disorder, it is not caused by depression, fatigue, or epilepsy. The problem is thought to be rooted in the brain at the level of the hypothalamus.

There is evidence of an association with the premature onset of REM sleep and the presence of changes in the HLA complex, which is actually a histocompatibility complex. However, these changes cause decreased levels of the neurotransmitter hypocrine.

Sometimes this decreased level can also be caused by infection or autoimmune reactions. In part, the disease may be hereditary, which increases its family incidence. However, secondary narcolepsy is the cause of other diseases, such as organic brain disorders and metabolic disorders.


Typical symptoms are excessive daytime sleepiness and acute sleep attacks without warning. These seizures cannot be suppressed by will and come at any time of the day, and the affected person cannot resist them.

Symptoms usually begin around the age of 10 and gradually increase in intensity. In addition to sudden sleep attacks, other symptoms are associated, such as a gradual loss of muscle tension, leading to other manifestations.

These include disturbances of consciousness, falling objects from the hands, and frequent falls due to breaking of the legs. The disease is also manifested by sleep paralysis, ie paralysis of the muscles during a sleep attack so that a person is not able to move.

Various hallucinations during a sleep attack are also typical. In some cases, the manifestations of the disease include aggression, hyperactivity in children, depression is common in adults, and people suffer from restless sleep during the night and often from nightmares.

Narcolepsy at work, at work with textiles, fallen woman under underwear. Photo source: Getty images
Frequent falls and interruptions of activity as a symptom of uncontrolled sleep. Photo source: Getty images

Symptoms of narcolepsy include:

  • excessive daytime sleepiness
  • cataplexy, loss of muscle tension, usually lasting seconds and up to 2 minutes
    • often as a result of emotion (laughter, anger)
    • sometimes it is associated with falling or breaking the knees
    • loss of the ability to speak, folk and loss of speech
    • various facial grimaces
    • head drop
    • it takes place all the time in consciousness
    • falling objects out of hands
    • aggravated, incomprehensible speech
  • hallucinations - in 40-80% of cases
    • mainly visual, less often auditory
    • feeling of touch or as if flying
    • hypnagogic hallucinations are like living dreams that are indistinguishable from reality
  • sleep paralysis, paralysis of the body, inability to move the body, limbs
  • intermittent and poor night sleep, insomnia
  • sleep apnea
  • nightmares
  • automatic activity without its perception
    • during the seizure, the person in question performs certain movements, continues to act
    • speaks certain words, inadequate to the situation
  • aggressiveness
  • hyperactivity in children
  • restless legs syndrome
  • depression may occur in adults
  • visual disturbances such as impaired, blurred or double vision may occur


EEG examination of a woman, electrodes on the head
EEG for brain activity monitoring. Photo source: Getty images

The disease is diagnosed on the basis of history. However, since the initial symptoms are not yet very intense and a certain disease may develop for a relatively long time. Other professional examinations, using EEG and  EMG, are also needed to make an accurate diagnosis.

During a longer interval during the day, the patient's electrical brain activity (EEG), as well as muscle tension and muscle signals (EMG), are measured. At the same time, it is possible to evaluate from these measurements whether a person really suffers from narcolepsy or is another disorder.

The examination method, which also uses EEG, EMG, and EOG (electrooculography - records eye movements), is polysomnography (PSG). Polysomnography is an all-night examination of sleep in a sleep laboratory.

It also evaluates respiration, respiratory movements of the chest and abdomen, blood oxygen saturation, ECG. A video is recorded during the examination. In daily polygraphy, MSLT is evaluated, which is a test of multiple sleep latency (from the English Multiple sleep latency test). 

Another method is to evaluate the presence of the HLA DQB1 * 602 allele and the level of hypocretin in cerebrospinal fluid. CT scan is used to rule out other brain diseases. Overall, in case of difficulties, we recommend a professional examination by a general practitioner and then a neurologist.


The disease occurs during childhood and adolescence, starting with vague symptoms and increased drowsiness. Hyperactivity or restless legs syndrome are also associated with childhood. In adulthood, depressive disorder or even aggression may be present

Later, muscle problems are added and bouts of sudden sleep, which cannot be stopped, are more common. The progression of the disease to its final form takes several years. Sometimes even ten years.

Between the ages of 30 and 40, the manifestations are most intense. In old age, the symptoms gradually alleviate. It is very important to have a professional examination and diagnose the disease as soon as possible.

Narcolepsy women at work, woman lying on office desk
Uncontrolled sleep at work. Photo source: Getty images

Sleep is therefore uncontrolled. It occurs during a normal day when shopping or talking. Excessive daytime sleepiness can also be manifested by cataplexy, but not in everyone affected. The term cataplexy includes loss of muscle tension.

This is the cause of frequent falls or knee breaking. Man falls out of the hands of subjects. He is unable to speak or his speech is incomprehensible. The muscles of the face create various grimaces. Or they are unable to hold their head and it will drop.

In some cases, hallucinations occur, which can give the impression of flying. It is common to perceive visual hallucinations that are not real. Sound sensations are less common, and feelings of touch or flying may be associated. Vivid dreams create an environment of reality.

Automatic activities manifest as a continuation of the activity or involuntary movements. For example, a person writes text on a computer, the seizure continues, but the written does not make sense. They also manifest themselves as saying words that do not fit into the context.

Sleep paralysis is the result of paralysis of the body, ie the inability to move. One can perceive but is not able to move. Sleep is of poor quality, paradoxically there is night insomnia. Sleep apnea may be present in some people.

Does narcolepsy limit life?

Of course, since the attack of narcolepsy occurs uncontrollably and cannot be influenced by the will. Imagine that you are crossing a pedestrian crossing and suddenly your life stops in the middle of the road.

It is similar in the case of a dialogue with another person, who may not have an understanding for a few seconds pause in the conversation. And as it would be in the case of a job, such as a waiter or a waitress. You can certainly imagine the consequence of a short-term loss of muscle tension.

Driving a motor vehicle or other means of transport could have fatal consequences. That's why a person with narcolepsy can't have a driver's license. Narcolepsy is a common cause of disability, and therefore a disability pension.

The ignorant public has no understanding of a person suffering from somnolence. It, therefore, limits his public and private life. It is the reason for reduced performance at school and adults at work.

Prevention of narcolepsy - sleep during the day, the right bed, mattress, bath, ambient temperature
The right bed, mattress, pillow, room temperature or a short sleep during the day will help. Photo source: Getty images

Preventive measures for narcolepsy include a healthy lifestyle and:

  • regular schedule during the day
  • regular sleep time
  • suitable room temperature at bedtime, the right mattress, and bed, the right type of pillow is also important
  • sufficient rest, sleep even during the day (for a short period of time - 20 minutes) 
  • avoidance of alcohol, smoking, caffeine, drugs
  • restriction of heavy physical activity
  • sufficient physical activity
  • skipping heavy meals before bed
  • obesity

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Interesting resources

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