Narcolepsy, a public health problem, really? † press room

Excessive daytime sleepiness is increasingly being taken seriously by the scientific community. Credit: Unsplash

The tendency to drowsiness during the day is not uncommon: who has not already had a more or less urgent need to sleep after lunch or in the afternoon?

Often downplayed and considered a trivial problem caused by too little sleep, however, excessive daytime sleepiness can be the sign of a more serious pathology. In particular, one thinks of narcolepsy, a hypersomnolence that has been widely reported in the media in recent years and characterized by brutal and unstoppable sleep attacks that occur several times a day, sometimes while the person is at home. an activity.

In addition to this disease, which intrigues the public as well as scientists, many other health problems are also associated with excessive daytime sleepiness.

Far from being a harmless problem, excessive daytime sleepiness is therefore increasingly being taken seriously by both the scientific and medical community. Detox Channel takes stock.

Excessive Sleepiness: What Are We Talking About?

Excessive sleepiness or “hypersomnolence” is characterized by two main symptoms: an excessive amount of sleep (characterized by long nights and long naps) and a poor quality of wakefulness with often an unstoppable need to fall asleep.

Excessive sleepiness can have several causes. It can, of course, be caused by sleep deprivation, sometimes associated with other sleep disorders such as sleep apnea, circadian arrhythmias, and restless legs syndrome. It is also sometimes a symptom associated with certain metabolic diseases (obesity, diabetes) or psychiatric diseases (depression, bipolar disorder, etc.). It is estimated that excessive daytime sleepiness is present in 10 to 40% of individuals suffering from mood disorders. In addition, excessive sleepiness can be a side effect of certain psychotropic treatments.

Pathologies of central hypersomnolence, including narcolepsy, idiopathic hypersomnia, and Kleine-Levin syndrome, are rarer, even though they are increasingly featured in the media. They can have a real impact on patients’ quality of life. In France 10,000 to 30,000 people are affected by narcolepsy without a more precise figure being possible.

Whatever the origin of excessive sleepiness, there is ample evidence that its effects are harmful and should not be downplayed. Thus, in addition to the impact on the daily life and quality of life of those affected, the phenomenon often results in a decrease in academic and professional performance and domestic or work accidents. It is also one of the leading causes of death on the roads.

Excessive sleepiness is therefore a major public health problem and is at the heart of the research problems at Inserm, to develop interventions to improve the sleep of the population and better support people suffering from sleep disorders.

In the case of narcolepsy and hypersomnia, the priority is to clearly identify how these diseases arise and what biological mechanisms are involved in order to offer more specific and effective treatments and reduce diagnostic delays. Currently, people wait between eight and 10 years before being diagnosed.

Focus on narcolepsy: dynamic therapeutic research

There are two types of narcolepsy (type 1 and 2). Narcolepsy type 1, which is better defined, is clinically characterized by both daytime sleepiness and cataplexy (sudden – partial or total – decrease in muscle tone). The understanding of the biological mechanisms has yet to be deepened, but it appears that there is a loss of hypocretin neurons (neurons that synthesize a molecule called hypocretin or orexin) and that it is of autoimmune origin. Hypocretin regulates several physiological processes, including waking and sleeping, metabolism and the autonomic nervous system. It is deficient in patients with narcolepsy type 1.

Far from common ideas about the lack of dynamism of rare disease research, academic and therapeutic research on narcolepsy has made great strides in recent years.

The available therapeutic options aim to compensate for the lack of hypocretin by acting, for example, on neurotransmitters such as dopamine and norepinephrine, or even on a molecule called histamine, to increase alertness. These treatments are usually effective, but more personalized therapeutic options need to be developed and long-term side effects limited.

A few fairly recent developments should be highlighted. For example, the Montpellier Reference Center has made it possible – based on international collaborations and the work of several pharmaceutical companies – to demonstrate that a treatment called pitolisant, which acts on the histamine transporter, reduces daytime sleepiness and attenuates the manifestations of cataplexy. In addition, the drug solriamfetol, which acts on the transporter of dopamine and noradrenaline, also makes it possible to reduce the daytime sleepiness of narcolepsy: an innovative mechanism of action that allows a more effective and lasting action with few side effects. Both drugs are currently available for patients with narcolepsy.

In the past year, other pharmacological studies have been developed that aim to stimulate hypocretin 2 receptors to directly compensate for the deficiency observed in narcolepsy patients. The results are promising, but have not yet been published.

As the research progresses, scientists are seeking to develop more and more personalized approaches, matching each patient’s problems and needs, working hand in hand with them within sleep reference centers, including the coordination at the University Hospital of Montpellier, at the Institute of Neuroscience ( Inserm/University of Montpellier).

Text created with the support of Yves Dauvilliers, Unit 1061 Inserm/University of Montpellier, Neuropsychiatry: Epidemiological and Clinical Research

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