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Sleep … is the first great natural resource to be exhausted by modern man. The erosion of the nerves, not to be halted by any reclamation project, public or private.
IRWIN SHAW, ‘THE CLIMATE OF INSOMNIA’, THE NEW YORKER, 1949
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Sleep is one of the five great innate drives in humans. Disorder of this basic function is one of the most common health-related problems presenting to the GP. It may represent the clue to some very important disorders, such as depression, anxiety, adverse drug reactions, drug abuse and obstructive sleep apnoea (OSA). About half of the population report having some sleep-related problem in a year, with 25% of the Australian population reporting trouble getting enough sleep.1 Normal sleep requirement varies considerably.
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Sleep is divided into rapid eye movement (REM—also called dream sleep), as shown by EEG studies, and non-rapid REM sleep (NREM), which is subdivided into stages 1, 2, 3 and 4. Most stage 4 sleep (deepest) occurs in the first hours. REM sleep is accompanied by dreaming and physiological arousals; some dreaming occurs in NREM.
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Disorders of the sleep-wake cycle, which are invariably caused by a disruption of the body’s endogenous time clock, can result in insomnia or hypersomnolence (excessive sleepiness) or a combination of both. This is a feature of people experiencing the jet lag of international travel and shift workers.
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Key facts and checkpoints
Normal sleep: in a fit young person the ideal is 7.5–8 hours; latency <30 minutes; wakefulness within sleep usually <5% of time.
Humans can stay awake without a problem for 16–18 hours. Sleepiness is wake-state instability.
The evaluation of sleep disorders involving the sleep-wake cycle is enhanced by the patient keeping a sleep chart.
It is important to take a drug history from patients complaining of insomnia or hypersomnolence.
Drugs that can disturb sleep include alcohol, nicotine, antihistamines, selective serotonin reuptake inhibitors (SSRIs), caffeine, hypnotics, venlafaxine, selected β-blockers, β2-agonists, theophylline, corticosteroids, sympathomimetic agents.
Sleep disorders in children, including snoring, should be taken seriously and investigated. They have many consequences, such as learning difficulties, hyperactivity, behavioural disorders, failure to thrive and short stature.
Be wary of young people and others presenting with insomnia with some urgency, especially requesting temazepam capsules—they may be dependent on benzodiazepines.
People with OSA usually present with the TATT syndrome—‘tired all the time’. These patients are often unaware of waking or becoming aroused during the night.
A patient who snores, has witnessed apnoeas and sleepiness is likely to have OSA.
The majority of cases of excessive somnolence are caused by OSA and narcolepsy.2
Non-pharmacological therapies, which include basic education and practice of sleep hygiene and behavioural therapy, should be used in management wherever possible.
Referral to the new generation specialist sleep disorder centres provides enhanced objective evaluation, diagnosis and treatment of the more complex disorders.
It is illegal for a driver with a ...