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Sleep … 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 a fundamental need 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), which is the most common form of sleep disordered breathing. About half of the population report having some sleep-related problem in a year, and 25% of the Australian population report trouble getting enough sleep when asked.1 Normal sleep requirement varies considerably.
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EEG studies indicate that sleep is divided into rapid eye movement (REM—also called dream sleep) 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 familiar to shift workers and people with jet lag.
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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 those complaining of insomnia or hypersomnolence.
Drugs that can disturb sleep include alcohol, nicotine, antihistamines, SSRIs, caffeine, hypnotics, venlafaxine, selected β-blockers (e.g. propranolol), β2-agonists, theophylline, corticosteroids, sympathomimetic agents.
Sleep disorders in children, including snoring, should be taken seriously and investigated. They have many potential consequences, such as learning and behavioural difficulties, hyperactivity, failure to thrive and short stature.
A claimed or actual presentation of insomnia accompanied by a medication request, particularly by a younger person, can reflect benzodiazepine dependency.
People with OSA usually present with the TATT syndrome—‘tired all the time’—or excessive daytime sleepiness. 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 a specialist sleep disorder centre provides enhanced objective evaluation, diagnosis and treatment of the more ...