AQA PSYA3 - Biological Rhythms - Insomnia


Insomnia involves problems of quality and duration of sleep. It leads to daytime tiredness. Symptoms include taking more than 30 minutes to fall asleep, sleep efficiency of less than 80% and increased night-time awakenings.

It's diagnosed when the sleep difficulties have lasted over 1 month and daytime fatigue affects work, social or personal functioning.

Primary Insomnia

When no obvious external cause is observed, assumed that the cause must lie in the brain systems controlling sleep.

Brain mechanisms

  • There are centres in the brain controlling the ultradian rhythm of sleep using neurotransmitters such as noradrenaline and serotonin. If a slight malfunction occurred it could affect sleeping patterns and cause insomnia.
  • Reimann (2010) found a genetic component in insomnia through family studies suggesting that the imbalanced sleep mechanism could be inherited (links to the fact that the SCN represents an inherited inbuilt biological clock).
  • A post mortem on a man called Michael Cork who suddenly found himself unable to sleep showed lesions in two areas of the thalamus (forebrain) which were linked to sleep and hormonally controlled circadian rhythms.

Learned insomnia

  • People often experience insomnia during periods of stress and sleeping patterns return to normal after stress has subsided. In some people the sleeping patterns do not return to normal, even though the original stress has gone, the person may still worry about sleeping leading to learned primary insomnia. 
  • An individual may develop bad habits such as trying too hard to sleep (becoming…


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