Narcolepsy: causes, symptoms, treatment and drug therapy

By Cristiano Antonino On Jul 20, 2022

Narcolepsy (narcolepsy) is a chronic neurological disorder manifested by hypersomnia, i.e. excessive daytime sleepiness

The hypersomniac patient is unable to remain alert throughout the day, may experience sudden sleep situations from which he cannot escape (e.g. he may fall asleep during a conversation, during a meal or even while driving), and may have great difficulty waking up in the morning.

It can be difficult for a sufferer to stay awake during school or work hours, which makes it difficult – if not impossible for the narcoleptic – to carry out certain professions where it is necessary to maintain concentration for long periods.

What causes narcolepsy?

Narcolepsy is a disorder whose underlying cause is not yet known.

Recent research has shown that several neurotransmitters are involved.

The most important of these is hypocretin (also known as orexin), which in narcoleptics has been shown to be reduced in the CSF, until it disappears completely in 90% of narcolepsy sufferers with cataplexy.

A reduction in hypothalamic neurons secreting this compound has also been shown in autopsy findings of affected subjects.

Only 1% of cases of narcolepsy have a family history. The risk of finding narcolepsy among first-degree relatives is 1% to 2%, i.e. 30 to 40 times higher than in the general population.

This means that genetic factors play a major role in this disorder.

Characteristics of sleep attacks

they can last approximately 15 to 60 minutes each;
they may occur several times during the course of a day;
they usually occur after eating, but can occur at any time, such as while driving, talking to someone, or during other situations where there is little movement;
in some individuals, the intensity of the attack is characterised by a discrete temporal progressiveness that allows them to consciously interrupt their actions and retreat to a suitable place before collapsing to sleep.

Sometimes the person may have dream hallucinations before sleeping or during an attack.

When one wakes up, one feels rested even after a brief attack.

Narcolepsy may also be associated with a temporary and sudden muscle weakness called cataplexy, which is usually caused by strong emotions

This may be associated with emotional reactions such as anger or laughter and be similar to epileptic seizures and may involve

sudden loss of muscle tone;
temporary inability to use muscles (sleep paralysis): this condition occurs immediately after waking up or with the onset of drowsiness.

Symptoms of narcolepsy

sudden sleep attacks, one or more times a day
excessive daytime sleepiness (the narcoleptic experiences a strong urge to fall asleep every 2 hours);
cataplexy (loss of strength caused by strong emotions such as laughter, embarrassment, anger until falling to the ground);
sleep paralysis (the narcoleptic finds himself completely paralysed before falling asleep or immediately after waking up, remaining fully conscious)
hypnagogic hallucinations (the narcoleptic daydreams often interacting with reality).

If you have any doubt that your neurological disorder is narcolepsy, the first symptom that appears is excessive daytime sleepiness; cataplexy can occur within 1-4 years of the onset of sleepiness, but can be as late as 40-60 years.

There is a rapid and atypical onset of REM sleep within 15-20 minutes of falling asleep, you may have daytime bouts of sleep every 90-120 minutes, with naps of 5-15 minutes during which you then remember dreaming and also feel sufficiently rested, on the whole you still have a fair amount of resistance to sleep between one resting episode and the next.

How is narcolepsy diagnosed?

For a correct diagnosis of narcolepsy, it is not sufficient to assess only the clinical symptoms, it is essential to refer to a sleep centre for an accurate instrumental diagnosis.

To make the diagnosis of narcolepsy, the subject must have complained of near-daily daytime hypersomnia for at least three months, which may be associated, when present, with a history of cataplexy.

The anamnestic findings must be confirmed by performing the Multiple Sleep Latency Test (MSLT).

MSLT is a daytime test where 4-5 times during the day the patient is asked to try to fall asleep.

Each session can last up to 35 minutes and is interspersed with a 2-hour break.

The finding during MSLT of an average falling asleep latency of less than 8 minutes and the onset of REM sleep in at least two of the sessions is considered indicative of pathology.

An overnight polysomnography, usually performed the evening before the MSLT session, may show an early onset of REM sleep after falling asleep.

Alternatively, the anamnestic data can be confirmed with a CSF hypocretin-1 assay, which must be ≤110 ng/l.

How many people suffer from narcolepsy?

Narcolepsy appears to have no family history, in fact only 1% of cases have a family predisposition and appear between the ages of 15 and 25.

The disorder of narcolepsy is probably underdiagnosed worldwide; it occurs in 0.2-2 cases per 1000 inhabitants and only 10-15% of narcoleptics present with all symptoms, furthermore, 85-100% of narcoleptic patients have the same histocompatibility antigens (i.e. they have a similar predisposing genetic make-up).

Is the use of drugs for narcolepsy recommended?

Only symptomatic drugs are recommended for narcolepsy with cataplexy, however, these are substances that alleviate/resolve one or more symptoms of the disorder, but do not cure what triggers this neurological disorder.

Therapies for narcolepsy

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The most effective non-pharmacological therapy is based on short restorative naps (a few minutes to a maximum of 1 hour) that allow the body to endure a few hours, after which drowsiness reappears.

These short sleep phases can vary from 6-7 per day. Adults can help themselves with the use of caffeine, which should absolutely be avoided in children.

Drug therapy involves taking one of the following medications as appropriate:

Modafinil;
Sodium Oxybate.

Modafinil activates wakefulness; in adults it is taken as tablets spread throughout the morning to control daytime drowsiness.

Taking Modafinil in the early afternoon hours is strongly discouraged as it may disturb sleep the following night.

There is not much data on the study of Modafinil in children, some show effects by taking the same dose as adults, while others only need half the dose.

Generally, side effects are mild and may include headaches, anxiety, nervousness and rhinitis.

Sodium Oxybate has sedative and anaesthetic properties, basically inducing deep sleep, is taken as a syrup before going to bed and a second dose should be taken after about 3 hours.

The most effective way to combat daytime sleepiness is to combine sodium oxybate at night with modafinil during the day.

The side effects of Sodium Oxybate are:

nausea;
somnambulism;
weight loss;
confusion on waking;
enuresis;
high blood pressure;
dizziness;
headache.

The drugs mentioned above are not a definitive cure: they only treat the symptoms but not the underlying disorder.

However, some recommended behaviours seem to reduce the onset of sleep attacks:

eating fruit and vegetables during the day and avoiding heavy meals before important activities;
planning a short nap (10 to 15 minutes) after meals if possible;
planning a nap to control daytime sleep and reduce the number of unexpected and sudden sleep attacks.

Teachers and supervisors should be informed of the condition of those with narcolepsy so that they are not punished for being ‘lazy’ at school or work.

Possible complications

Narcolepsy is a chronic, lifelong illness.

It is neither life-threatening nor dangerous in itself, but can become so if episodes occur while driving, operating machinery or similar activities.

In this regard, it is important that narcolepsy is controlled with sleep therapy to limit the risk of possible complications, which are: