Danish scientists shed new light on overwhelming need to sleep

Between 1,200 and 3,000 Danes suffer from narcolepsy, as this disorder is called. During the sudden attacks, sufferers experience an extreme craving for sleep. New Danish research indicates that narcolepsy is an autoimmune disorder. 

An autoimmune disease is when the body attacks itself, as it does, for instance, in the case of arthritis or psoriasis.

But does this also apply to narcolepsy where a sufferer is suddenly overtaken by a deep, irresistible urge to sleep?

The hypothesis that narcolepsy is actually an autoimmune disease has been researched for some years – and results are now emerging which appear to confirm this theory.

The first scientific article that seems to prove the hypothesis was published in Nature at the end of 2018, and a team of Danish scientists recently followed it up with an article in Nature Communications.

Their work was funded by the Lundbeck Foundation and the team was headed by two Lundbeck Foundation Fellows: Associate Professor Birgitte Rahbek Kornum from the Department for Neuroscience, University of Copenhagen, and Professor Sine Reker Hadrup from DTU Health Technology, Technical University of Denmark.

Researchers from Rigshospitalet, University of Copenhagen (Danish Centre for Sleep Medicine) also participated, and Professor Sine Reker Hadrup explains that the overall results appear to support the hypothesis that narcolepsy is an autoimmune disease:

‘We were the first to discover that the body is able to detect specific neurons that play a key role in connection with narcolepsy. And if it can do this, the body will also be able to target these neurons via an autoimmune response.’

Rare disease

It is estimated that narcolepsy affects 20-50 out of 100,000 people. Consequently, it must be assumed that between 1,200 and 3,000 Danes suffer from the disease.

Sleep attacks experienced by narcolepsy sufferers usually last several minutes – but can easily last longer. Narcolepsy is typically treated with drugs that stimulate the central nervous system.

Sine Reker Hadrup explains that a group of neurons in the brain are incapacitated in people who suffer from narcolepsy:

‘These neurons produce a chemical known as hypocretin – a neurotransmitter which regulates our sleep. With regard to the hypothesis that narcolepsy is attributable to an autoimmune response, our aim was to investigate whether the human immune system is able to localise these neurons. And we studied this in both narcolepsy sufferers and non-sufferers.’

The study showed that the immune systems of most of the subjects in both groups were able to detect the neurons that produce the sleep neurotransmitter hypocretin. However, the researchers also noted a particular state of alert in the immune systems of narcolepsy sufferers:

‘So even though we don’t yet know why a small number of people develop narcolepsy, while the majority aren’t affected by the sleep disorder, there’s now plenty of indication that narcolepsy can be characterised as an autoimmune disease,’ says Sine Reker Hadrup. 

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