Drowsiness is a symptom that results in a strong urge to sleep. It is normal, “physiological”, when it occurs in the evening or at bedtime, or in the early hours of the afternoon. If it occurs during the day, it is called daytime sleepiness. While drowsiness can affect anyone, especially when tired, after a bad night’s sleep, or right after a big meal, it becomes abnormal when it is repeated daily, interferes with attention, and interferes with daily activities.

It can reveal the presence of a pathology and must therefore be the subject of a medical consultation.

Drowsiness is a common symptom: studies have estimated that it affects around 5 to 10% of adults (intensely, and 15% “mild”). It is very common in adolescence and in the elderly.

It stands to reason that drowsiness may simply be related to lack of sleep, especially in adolescents. We know that they do not sleep enough for their needs, and daytime sleepiness is common in this age group.

Apart from an unusual situation, which can affect everyone (bad night, jet lag, lack of sleep, etc.), drowsiness can be associated with several sleep pathologies:

• phase delay and chronic sleep insufficiency: this is a chronic lack of sleep or a disorder of the internal clock, which “shifts” the phases of sleep (this is common in adolescents)
• sleep disorders such as snoring and obstructive sleep apnea syndrome: this is the most common cause of drowsiness (after insufficient sleep). This syndrome manifests as unconscious breathing “pauses” during the night, which impairs the quality of sleep by constantly interrupting rest cycles.
• central hypersomnias (narcolepsy with or without cataplexy): they are most often due to a degeneration of certain neurons in the brain which leads to fits of sleep, with or without cataplexy, that is to say a sudden loss of muscle tone . It is a rare disease.
• hypersomnia due to the taking of drugs: several drugs and drugs can induce excessive drowsiness, in particular sedative hypnotics, anxiolytics, amphetamines, opiates, alcohol, cocaine.

Other disorders can also be associated with drowsiness:

• psychiatric conditions such as depression or bipolar disorder
• obesity or overweight
• diabetes
• others: neurodegenerative diseases, stroke, brain tumor, head trauma, trypanosomiasis (sleeping sickness), etc.

Pregnancy, especially in the first trimester, can also cause irrepressible fatigue and daytime sleepiness.

The consequences of excessive sleepiness are multiple and potentially serious. Drowsiness can indeed be life threatening: it is even the leading cause of fatal road accidents and is believed to be involved in a total of 20% of road accidents (in France).

On the professional or school side, daytime sleepiness can cause concentration problems, but also increase the risk of work accidents, impair cognitive functions, increase absenteeism and lower performance.

Social and family consequences should not be neglected either: it is therefore essential to diagnose drowsiness (the affected person does not always spontaneously consult their doctor) and find the cause.

The solutions to be implemented obviously depend on the cause. When drowsiness is due to fatigue or lack of sleep, it is important to restore regular bedtime and try to get enough sleep each night.

When drowsiness reflects the existence of a sleep apnea syndrome, several solutions will be proposed, in particular the wearing of a respiratory mask at night to prevent apnea. If necessary, weight loss should be considered: it often reduces symptoms and reduces the cardiovascular risk associated with apnea.

In the event of drug-induced drowsiness, withdrawal or reduction of doses will be required. Medical help is often needed to do this.

Finally, when the drowsiness is due to a neurological or systemic pathology, appropriate management can generally reduce the symptoms.