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Sleep disorders: insomnia and narcolepsy
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For some people, sleep goes wrong. Two sleep disorders on the specification are insomnia and narcolepsy.
Insomnia
Symptoms: difficulty falling asleep, waking in the night and struggling to get back to sleep, or waking too early. This leads to daytime tiredness, poor concentration and irritability.
It can be short-term (for example before exams) or long-term (chronic): often defined as at least three nights a week for at least three months.
Explanations: primary insomnia has no other underlying cause and may come from habits such as worrying in bed. Secondary insomnia is caused by something else, such as stress, anxiety, pain, caffeine, some medicines, or a disrupted body clock (shift work, jet lag, screens late at night). Some people may inherit a tendency towards it.
It can be short-term (for example before exams) or long-term (chronic): often defined as at least three nights a week for at least three months.
Explanations: primary insomnia has no other underlying cause and may come from habits such as worrying in bed. Secondary insomnia is caused by something else, such as stress, anxiety, pain, caffeine, some medicines, or a disrupted body clock (shift work, jet lag, screens late at night). Some people may inherit a tendency towards it.
Narcolepsy
Symptoms: extreme daytime sleepiness and sudden sleep attacks, falling asleep without warning. Many people also have cataplexy: sudden loss of muscle control triggered by strong emotions such as laughing. Other symptoms include sleep paralysis and vivid hallucinations when falling asleep or waking.
People may enter REM sleep very quickly, rather than after the usual stages.
Explanations: many people with narcolepsy have very low levels of hypocretin (also called orexin), a brain chemical that helps keep us awake. This may be because the immune system has damaged the cells that make it. There is also a genetic link.
People may enter REM sleep very quickly, rather than after the usual stages.
Explanations: many people with narcolepsy have very low levels of hypocretin (also called orexin), a brain chemical that helps keep us awake. This may be because the immune system has damaged the cells that make it. There is also a genetic link.
Comparing the two
The two disorders are almost opposites: one is too little sleep, the other is sleep at the wrong times.
A student keeps falling asleep in lessons without warning and sometimes goes weak at the knees when laughing. Which disorder fits, and what is the second symptom called?
- Sudden sleep attacks in the day suggest narcolepsy.
- Losing muscle control when laughing is cataplexy.
Answer: Narcolepsy; the muscle weakness is cataplexy.
Insomnia means trouble falling or staying asleep or waking too early; it can be primary or caused by stress, caffeine or a disrupted body clock. Narcolepsy causes sudden sleep attacks and often cataplexy, and is linked to low levels of hypocretin (orexin) and genetics.
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