Sleep Disorder


Sleep Disorders

Key Terms:

  • Insomnia – a long-term problem initiating and/or maintaining sleep.
  • Primary insomnia – insomnia not attributable to an underlying cause.
  • Apnoea – a medical condition where sleepers have persistent pauses in breathing. 
  • Personality factors – dispositional traits affecting normal sleep patterns.
  • Sleepwalking – performing unconscious activities when asleep.
  • Narcolepsy – a sleep disorder characterised by falling asleep at unexpected times.
  • Sleep paralysis – a sleep disorder involving an inability an inability to move at the onset or on wakening.

Explanations for Sleep Disorders


  • Insomnia is ‘the inability to sleep’, where sufferers have a long-term problem initiating or maintaining sleep.
  • Insomnia can take the form of inadequate quantity or quality of sleep.
  • Insomnia affects women more than men, possible because of hormonal fluctuations associated with onset of menstruation and the menopause; however, only 5 – 10% of sufferers are diagnosed with insomnia.
  • Dement (1999) – argues that insomnia is not a sleep disorder, but rather a symptom with different causes.
  • He concedes that it is often easier to refer to insomnia as if it were a single disorder, and that doctors treat insomnia directly rather than some unknown underlying cause.
  • Primary insomnia is when the insomnia is regarded as an illness in itself.
  • Secondary insomnia is when insomnia develops in a direct result of another illness.
  • Insomnia affects both physical and cognitive functioning.
  • Symptoms consist of; sleepiness, fatigue, decreased alertness, poor concentration, decreased performance, depression during the day and night, muscle aches and an overly emotional state.


  • It can be short-term and only last between a few nights, but less than 3 weeks.
  • It can be long-term (chronic), occurring most nights and for longer than 3 weeks.


  • Onset insomnia involves difficulty in getting to sleep, often associated with anxiety.
  • Middle-of-the-night insomnia is characterised by problems getting back to sleep after waking, or waking too early.
  • Middle insomnia involves waking in the middle of the night and/or difficulty staying asleep, often associated with medical illness or physical pain.
  • Late insomnia involves waking early in the morning, often associated with clinical depression.

Primary Insomnia

  • Primary insomnia is sleeplessness not attributable to a medical, psychiatric or environmental cause.
  • The diagnostic criteria for primary insomnia from the DSM-IV-TR, includes the following:
  • Difficulty initiating or maintaining sleep for at least 1 month.
  • The sleep disturbance, or associated daytime fatigue, causes clinically significant distress or impairment in social, occupational or other important areas of functioning.
  • The sleep disturbance does not occur during the course of other sleep-related disorders, such as narcolepsy or parasomnias.
  • The sleep disturbance does not occur during the course of another mental disorder.
  • The sleep disturbance is not due to the physiological effects of a substance, for example, drugs or a general medical condition. 

There are several sub-types of primary insomnia:

Psychophysiological insomnia:

  • This is a form of anxiety-induced insomnia sometimes called learned insomnia or behavioural insomnia.
  • The primary component is intermittent periods of stress resulting in poor sleep, creative maladaptive behaviours:
  • A vicious cycle of trying to


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