Hypersomnia is a disorder characterized by an excessive need for sleep. We often talk about secondary hypersomnia. It can have many different causes including a significant lack of sleep, severe physical fatigue and certain illnesses. There is also a rare form of primary or central hypersomnia, the origin of which is poorly understood.

Definition of hypersomnia

Hypersomnia is characterized by an excessive need to sleep. It can be expressed in different ways, and have many different causes. 

There are generally two types:

• secondary hypersomnia, the most frequent, which is the consequence of another phenomenon;
• primary hypersomnia, or central hypersomnia, the origin of which is much more complex, if not unknown.

Causes of secondary hypersomnia

It can follow:

• a significant lack of sleep;
• physical exhaustion;
• abrupt stopping of stimulants;
• excessive intake of hypnotics or sedatives;
• psychiatric illness;
• a neurological disorder such as trauma or neurodegeneration;
• an infection, in particular that with the Epstein-Barr virus or in the context of Guillain-Barré syndrome;
• an endocrine or metabolic disease such as diabetes or hypothyroidism;
• etc.

Types of primary hypersomnia

This form is still poorly understood. To date, there are three types of central hypersomnias:

• narcolepsy, a rare disease characterized by excessive daytime sleepiness and irrepressible sleepiness;
• recurrent hypersomnia or Kleine-Levin syndrome, a rare neurological pathology which results in episodes of hypersomnia extending over several days accompanied by cognitive-behavioral disorders;
• Idiopathic hypersomnia, a rare pathology resulting in permanent excessive daytime sleepiness accompanied by non-restful nighttime sleep of normal or longer duration.

Diagnosis of hypersomnia

It is initially based on a clinical and psychological examination. Secondly, additional examinations are carried out to confirm the diagnosis of hypersomnia and identify its origin. This in-depth analysis phase can be based on:

• the creation of a sleep diary, a method which asks the patient to postpone the duration and the quality of his phases of falling asleep, sleeping and awakening;
• actimetry, which consists of wearing an actimeter, a bracelet whose sensors make it possible to analyze the quality of sleep;
• nocturnal polysomnography which measures the quantity and quality of sleep using various instruments such as an electroencephalogram (EEG), an electro-oculogram or even an electromyogram;
• an iterative sleep onset latency test (TILE) which assesses the patient’s ability to fall asleep during the day;
• a maintenance-of-wake test (MTCT) which assesses the patient’s ability to stay awake during the day.

Secondary hypersomnia can affect anyone. The causes are multiple and can occur at any age. Primary hypersomnia is rarer. It mainly affects adolescents and young adults.

• Feeling of exhaustion: There is an urgent need to sleep. Depending on the form of hypersomnia, this feeling of exhaustion can be temporary or persistent.
• Excessive daytime sleepiness: During the day, hypersomnia is manifested by a state of drowsiness. This can have repercussions on daily activities: loss of attention, difficulty concentrating, etc.
• Long sleep: Hypersomnia results in an extension of the duration of sleep.
• Difficulties in waking up: Despite a long night’s sleep, difficulties in waking up are noted.

In the majority of cases, the treatment for hypersomnia involves treating its causes. Its objective will be to find restful sleep, that is to say a good quality of sleep. 

Depending on the case, treatment for hypersomnia may include:

• the implementation of hygienic and dietary measures;
• the prescription of psychostimulants, drugs to stimulate alertness;
• prescription of mood stabilizers, drugs to regulate mood.

Some secondary hypersomnias can be prevented by preserving or improving the quality of one’s sleep. To do this, it is particularly advisable to:

• get enough sleep (an adult sleeps about 7 to 8 hours each night);
• go to bed at night when fatigue is felt;
• have regular bedtime and wake-up times;
• take a nap if the night has been short;
• avoid overly large dinners;
• limit the consumption of exciting substances (coffee, tea, etc.), especially at the end of the day;
• favor a relaxing activity in the evening (reading, etc.);
• sleep in adequate conditions (little noise pollution, a temperature of 18-19 ° C, no screens in the bedroom, etc.).