Sleep disorders and insomnia

1. A sleep disorder is an ongoing problem with sleep that stops it doing its job, leaving the person tired through the following day.
2. The most common one is insomnia, and it comes in two forms.
3. It counts as insomnia when the problem happens on most nights, has gone on for weeks, and affects how the person copes in the daytime.

The two forms of insomnia

1. Sleep onset insomnia
   1. There is a long delay before sleep starts, so the person lies awake for a long stretch after going to bed.
   2. The night is cut short at the front end, so the person is still short of sleep by morning.
   3. It points to something keeping the body alert at bedtime, or a body clock that is not ready for sleep yet.
2. Sleep maintenance insomnia
   1. Sleep starts normally but does not hold, so the person wakes in the night, or very early, and cannot settle again.
   2. Sleep is both shorter and broken into pieces, so it restores less than an unbroken night of the same length.
   3. It points to something waking the person, or to a body clock timed too early.

A mistimed body clock

1. Sleeping and waking run on an internal clock that cycles roughly every 24 hours.
2. Sleep starts easily when that clock is timed to the hours of darkness, because the signal to sleep arrives at about the moment the person goes to bed.
3. Shift work, long-haul travel and a run of very late nights push the clock later than the world around it.
4. The sleep signal then arrives hours after bedtime, so the person lies awake and the pattern shows as sleep onset insomnia.
5. A clock running early brings the wake signal at 4am with no chance of dropping off again, which is sleep maintenance insomnia.
6. A fortnight of 2am bedtimes over the summer leaves the clock timed late for the first week of the autumn term.

High arousal at bedtime

1. Stress and worry keep the body keyed up, and sleep only comes once that arousal drops away.
2. Heart rate stays up and muscles stay tense, so the body is not in a state that lets sleep begin.
3. Worry about not sleeping then becomes a cause of its own, because checking the clock and counting the hours left adds to the arousal that is keeping the person awake.
4. High arousal usually produces sleep onset insomnia, and it also accounts for the 3am waking where the mind restarts on the same worry.

Habits and surroundings

1. Caffeine and other stimulants keep the body alert for hours after a coffee or energy drink late in the day.
2. Screens at bedtime slow the release of melatonin, because light from a phone held close to the face reaches the eyes, so the signal to sleep arrives later.
3. Irregular bedtimes give the body clock no steady pattern to settle into.
4. The physical environment matters too, because noise, light, heat and an uncomfortable bed wake a sleeper again and again, which is a common cause of sleep maintenance insomnia.
5. Pain and other health conditions break sleep into pieces, so insomnia often sits alongside another condition.
6. A late coffee, a phone in bed and a bedroom on a main road can each take a slice out of the same night, so these causes usually stack up.

The daytime effects of insomnia

1. Short or broken sleep leaves a person tired, slower to concentrate and more likely to make mistakes at work or in lessons.
2. Mood drops and patience runs short, so home life and school or work get harder to manage.
3. A doctor asks about these daytime effects as well as the night, because they form part of the definition.

Turning this into marks

1. When two causes are asked for, make them genuinely separate rather than the same cause worded twice, so stress and worry count as one cause between them.
2. Name sleep onset or sleep maintenance insomnia, because writing that the person sleeps badly does not secure the knowledge mark.
3. The mark most often lost is naming a cause without saying which form of insomnia it produces.