What is Narcolepsy and what drugs are the best for the condition?
Narcolepsy is a neurological disorder distinguished by the irresistible drowsiness, sudden falling asleep, and night sleep violation.
This disorder is one of the forms of paroxysmal hypersomnia, i.e. the enhanced, peak form of sleepiness, the reason of which is a weakening of neurotransmitter functions of the brain. There are numerous studies dedicated to narcolepsy yet the interest in further research persists. It is related to the fact that the pathology is quite unique and combines sleep disorder with difficult therapy. The incidence of narcolepsy is 0,04—0,16% of the total population. The typical signs of the condition can onset at the age of 5 to 50 years but most commonly they occur around the age of 30 years.
Narcolepsy study history
The term “narcolepsy” was introduced in 1880 by a French doctor Jean-Baptiste-Édouard Gélineau. He defined it as short irresistible daytime drowsiness episodes that occur after a certain period of time, and sudden episodes of muscle weakness later named “cataplexy”.
The clinical picture of narcolepsy has been later supplemented by other signs.
In 1930, Dr. Daniels added to the peculiarities of narcolepsy hypnagogic hallucinations (i.e. occurring when falling asleep) and sleep paralysis (being aware but unable to move or speak wen falling asleep or waking up).
This was later supplemented with microsleep (may be from fractions of a second to thirty seconds) by Dr. Yoss, Dr. Daly, Dr. Vogel.
Manifestations of narcolepsy
The typical manifestations of narcolepsy are:
1) Irresistible sleepiness with recurring micro sleepiness attacks during the daytime;
2) Cataplexy (sudden short-lived episodes of muscle weakness of different severity triggered by emotional state changes);
3) Hypnagogic or less commonly hypnapompic hallucinations (vivid visions occurring when falling asleep or awakening);
4) Cataplexy when awakening or falling asleep (sleep paralysis);
5) Violation of night sleep with frequent waking ups, nightmares, difficulty falling asleep after waking up.
In multiple narcolepsy studies, there are provided clinical and polygraphic peculiarities of sleep and wakefulness in the disorder. The most typical polygraphic indicators are the sleep latency (sleep onset) of less than ten minutes and the start of the sleep from REM (Rapid eye movement sleep in which vivid dreams occur).
What causes narcolepsy?
It had been established that an important role of the disease onset plays the autoimmune (wrongful immune response of the body) destruction of the hypothalamus neurons which leads to the drop in the volume of hypocretin-1 level cerebrospinal fluid which is a neurotransmitter responsible for wakefulness. The factors that can contribute to the development of this chain of reactions are:
- Brain injuries;
- Infectious diseases;
- Genetic predisposition.
What causes narcolepsy attacks?
There are no indications that narcoleptic sleepiness attacks need a trigger to onset. However, cataplexy, i.e. a sudden severe weakness of muscles which can result in falling while not losing consciousness, can be triggered by intense emotions, stress, physical activity, change of the position, i.e. from sitting to standing up.
Besides, sometimes people before the sleepiness attack can manifest an unusual behavior such as become aggressive or, on the contrary, joyful and talkative.
How is narcolepsy diagnosed?
Narcolepsy diagnosis is made based on the sleep tests but to know whether an individual needs them or not, they should go to a physician who will then appoint the tests based on the complaints if they meet suspected narcolepsy diagnosis. Or, if a person notices that he or she experiences the symptoms described in this article, they can go to a somnologist, a specialist in sleep disorders who has more experience in identifying narcolepsy by the complaints and physical examination than a regular physician.
The tests for narcolepsy include:
- Multiple sleep latency test (MSLT);
- Computed tomography and magnetic resonance imaging of the head.
How is narcolepsy treated?
The therapy of the disease available today is able to ease the symptoms but not cure the condition because the precise causes of narcolepsy and the processes that lead to the onset of sleepiness attacks are not fully understood. But since a person with the disorder suffers from daytime sleepiness comparable to the sleepiness experienced by a healthy individual deprived of sleep for 48 hours, the main therapy is based on psychostimulants from the class of phenethylamines (amphetamine and methylphenidate), and drugs based on a new type of psychostimulant, Modafinil and its enantiomers (Armodafinil) and precursors. The second group of the medications is more preferable because it is proven to have minimum harm on the body and maximum effect on wakefulness, ensuring around 10-12 hours without sleepiness attacks, or at least wakefulness level that allows staying awake even when an attack occurs.
Antinarcoleptic drugs comparison
In some countries, these groups of medications are not approved for the treatment of narcolepsy so instead less effective and potent medicines are used such as brain-stimulating antidepressants (usually, o imipramine and venlafaxine) and sleeping pills that improve and stabilize night sleep.
There is also a behavioral approach to narcolepsy management that consists of the following of sleep hygiene which implies "planned falling asleep", following of the regimen of going to bed and waking up, working only during the daytime, and dosed physical activity.
How can be narcolepsy prevented?
To date, the main cause of narcolepsy development had not been established. Thus, the preventive measures cannot guarantee that you don’t develop it, especially if some of your close relatives has the disorder. However, the onset of the disease can be delayed by adhering to a healthy lifestyle:
- A healthy diet with the vegetables and fruits being the main source of calories;
- Regular exercising;
- Abstinence from alcohol, drugs, and smoking;
- 8:00 night's sleep;
- Stress reduction;
- Favorable climate in the family.