ItвЂ™s no coincidence that every organism on Earth with any kind of neural cluster resembling a brain performs something akin to sleep. Chronic sleep deprivation puts you at greater risk of a whole host of conditions: cancer, stroke, type 2 diabetes, depression, hypertension, obesity, the list goes on. Sleep is doing so many things for us: itвЂ™s strengthening connections in the brain, making new ones, pruning ones we donвЂ™t need. Why is it so important to get good sleep? We still need to get much better at spotting these disorders. There are stories of people going 20, 30, even 60 years before being diagnosed, by which time the psychological damage can be serious. Narcolepsy is a rarer disorder, affecting about 1 in 2,500. Sleep apnoea is the other common one, which is when a personвЂ™s breathing is interrupted during sleep вЂ“ snoring is often a sign of this. How common is narcolepsy compared to other sleep disorders?ДЄt any one time, chronic insomnia affects about 10 per cent of the population. IвЂ™ve found drugs to control most of my symptoms, but IвЂ™m fortunate вЂ“ not everyone responds to them. There are stimulants such as modafinil and dexamphetamine that help to keep us alert, and small doses of antidepressants can treat the cataplexy. At the moment, thereвЂ™s no cure, because once youвЂ™ve lost these cells theyвЂ™re gone. The immune system destroys the invaders, but in some cases it also takes out a population of cells in the brainвЂ™s hypothalamus that produce proteins called hypocretins, which play a crucial role in sleep regulation. The vast majority of cases are caused by an infection such as flu or, as in my case, a streptococcal infection. Paradoxically, people with narcolepsy tend to experience fractured night-time sleep too, waking up as many as 20 or 30 times a night: it destroys your sleep quality. I used to see an axe murderer вЂ“ IвЂ™d feel the axe as it slammed into my chest, and the blood trickling down my sides. The brain often manufactures petrifying visions. It happens when the brain is in rapid eye movement (REM), dreaming sleep, but youвЂ™re awake, unable to move. Many people with narcolepsy also experience sleep paralysis and hallucinations when theyвЂ™re waking up or dropping off. If youвЂ™re collapsing 100 times a day, it can be an extremely disabling condition where you become fearful of leaving the isolated safety of your home. The attacks usually last only 10 or 20 seconds, but thereвЂ™s very little warning, and it can be exhausting. ThatвЂ™s even funnier, and it keeps you under for a while longer. And then someone comes up and says, вЂњIs he okay? Does he need an ambulance?вЂќ. YouвЂ™re in a crumpled heap on the floor, laughing your head off inside, but you just look asleep or dead. WhatвЂ™s fascinating is that you retain consciousness throughout. It can be any emotion, but the most common trigger is humour вЂ“ I have a friend who only needs to raise an eyebrow to have me on the floor. ItвЂ™s the same process that happens during sleep to stop you acting out your dreams, but during the day, it can mean that even a small emotion has you collapsed on the floor. Most people with narcolepsy also experience cataplexy, which is where the emotional centre in the brain causes a sudden loss in muscle control.

This was my first symptom when I was diagnosed вЂ“ IвЂ™d find myself dozing through tutorials at university and overdosing on caffeine.Д«ut thatвЂ™s probably the least interesting of the symptoms. Most people know that those with narcolepsy have an irresistible need to sleep at inappropriate moments during the day. But, he tells us, itвЂ™s a largely misunderstood condition. At the age of 21, he was diagnosed with narcolepsy вЂ“ a rare disorder that causes people to fall asleep without warning. Henry Nicholls is more qualified than most to write about the science of sleep.

Cataplexy laughing