Sleepy Days & Sleepless Nights

'Coping with Narcolepsy' by Kelly McLarnon.

Sources: Vyse, T. Narcolepsy and the T-cell receptor. Nat Genet 41, 640–641 (2009). https://doi.org/10.1038/ng0609-640 and https://eu-nn.com/what-are-the-symptoms-of-narcolepsy/

In the book ‘The Mysterious Benedict Society’ by Trenton L. Stewart, the very mysterious Mr. Benedict suffers from a condition called narcolepsy. He can fall asleep at any time – while walking down stairs, making an omelet, and even while shaving – and he cannot control when he falls asleep! When he does fall asleep, it’s usually for a very short duration (about a minute or two), but he falls into a very deep sleep, called REM sleep, that normally only happens when you sleep at night. In the book, Mr. Benedict tells us that these sleep attacks are sometimes caused by strong emotions – either good or bad [1]. So, strong feelings of happiness, anger, fear, or sadness may trigger sleep attacks!

We don’t know a lot about narcolepsy. Doctors define narcolepsy as a disorder that decreases your ability to regulate your sleep-wake cycles [2]. Men and women are equally likely to develop narcolepsy, with symptoms usually starting when they are adolescents or young adults [3,4]. The four most common symptoms of narcolepsy are cataplexy (loss of muscle function), sleep paralysis (being unable to move or talk when falling asleep or waking up), hallucinations (seeing and/or hearing vivid, dream-like illusions) and excessive day-time sleepiness no matter how long they slept in the night [5,6]. People with narcolepsy may suffer from one or more of these symptoms, with varying degrees of severity. Some people with narcolepsy experience less common symptoms such as automatic behavior, where they seem awake while performing tasks but later wake up with no memory of doing so and insomnia, or difficulty falling asleep at night [2,6,7]. Interestingly, individuals with narcolepsy tend to sleep the same number of hours as people without, but their quality of sleep is much worse.

The exact cause of narcolepsy is unknown; however, scientists are beginning to identify some potential causes. Neuroscientists discovered damage to certain brain cells, or neurons, in the hypothalamus, a region that regulates sleep-wake cycles, in people with narcolepsy that is caused by improper immune system responses. There is also a strong genetic component to the disease. Patients with narcolepsy tend to have family members suffering from the same condition, suggesting that it is possible for narcolepsy to be inherited genetically [6]. Scientists have found genetic mutations that may increase the possibility of developing narcolepsy [6]. However, not everyone with these mutations develop narcolepsy, so there must be factors other than genetics that cause the disease. For example, scientists discovered that individuals who get sick with respiratory viral infections, like the flu, might be more likely to develop narcolepsy [6,7]. In fact, during the H1N1 epidemic in 2009, there was a global increase in narcolepsy diagnosis! [6]

It is difficult for doctors to diagnose narcolepsy because there are so many potential causes, and the symptoms of narcolepsy are hard to identify. Many symptoms of narcolepsy are often observed in other diseases, and people with narcolepsy have many different combinations of symptoms [6]. There are specialized sleep tests designed to help doctors diagnose narcolepsy, which measure a patient’s duration of REM sleep or estimate the average time they require to enter REM sleep [7]. Sadly, there is no cure for narcolepsy, but people with narcolepsy can improve their symptoms with prescription medications or lifestyle changes [6]. 

Around the world, it is estimated that roughly 25–50 people for every 100,000 people are diagnosed with narcolepsy [6,8]. However, scientists believe that the actual number is much higher as many parts of the world do not have the resources to survey the population for such rare diseases [6,8]. Furthermore, most narcolepsy diagnoses are made based on questionnaires and not specialized sleep tests making it quite easy for many people with narcolepsy to remain undiagnosed [6]. This means that, on average, those with narcolepsy have to wait nearly a decade for the diagnosis! Narcolepsy seriously impacts people’s lives and we need more research to understand how to identify and treat it better. 

Glossary 

• Narcolepsy – a chronic sleep disorder impacting one’s ability to regulate sleep-wake cycles

• REM sleep – (also known as rapid eye movement sleep) is a phase of sleep that is characterized by the rapid movement of eye. It’s during this stage that we tend to dream vividly. 

• Cataplexy – sudden muscle weakening that occurs while the person is awake. It is temporary. 

• Sleep Paralysis – being unable to move and talk when falling asleep or waking up.

• Hallucinations – vivid dream-like experiences. There can have visual and/or auditory inputs.

• Excessive Day-Time Sleepiness – extreme sleepiness during the day. It is consistently and occurs even with a good night’s sleep.

• Automatic Behavior – behavior that a person performs, as though they are awake, but later have no memory of these actions. 

• Insomnia – inability to fall asleep at night. 

• Neuroscientist – a scientist that studies the brain, its functioning and its diseases. 

• Hypothalamus – a region in the brain. It has many functions – one of which is to regulate the sleep-wake cycles. 

• Genetic Mutations – accidental change in the genetic material

References

1. Stewart, T. L. The Mysterious Benedict Society. (Little, Brown and Company, 2008).

2. Narcolepsy | National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/disorders/narcolepsy.

3. Silber, M. H., Krahn, L. E., Olson, E. J. & Pankratz, V. S. The Epidemiology of Narcolepsy in Olmsted County, Minnesota: A Population-Based Study. Sleep 25, 197–202 (2002).

4. Dauvilliers, Y. et al. Age at onset of narcolepsy in two large populations of patients in France and Quebec. Neurology 57, 2029–2033 (2001).

5. Yoss, R. E. & Daly, D. D. On the Treatment of Narcolepsy. Med. Clin. North Am. 52, 781–787 (1968).

6. Kornum, B. R. et al. Narcolepsy. Nat. Rev. Dis. Primer 3, 1–19 (2017).

7. Scammell, T. E. Narcolepsy. N. Engl. J. Med. 373, 2654–2662 (2015).

8. Hublin, C., Partinen, M., Kaprio, J., Koskenvuo, M. & Guilleminault, C. Epidemiology of Narcolepsy. Sleep 17, S7–S12 (1994).

Edited by Alexandra Fink