Disorders of sleep Flashcards
Insomnia
A condition where people experience difficulties sleeping, affecting both the quality and length of their sleep.
Primary insomnia- chronic insomnia with no obvious cause
Secondary insomnia- chronic insomnia with underlying medical of psychological conditions that could explain it.
Personality factors
There are two areas of sleep research that study personality in relation to insomnia. Clinical anxiety and chronotype.
Clinical anxiety
Clinical anxiety is a medical disorder defined by excessive feelings of worry or, even intrusive thoughts about certain fears. It has been found to be one of the main causes of secondary insomnia.
Supported by:
CBT (which aims to decrease anxiety levels) is used to fight insomnia.
Twin studies - which show that high levels of sleep disturbance link to high levels of neuroticism (Heath et al 1998).
Neuroticism- a personality type characterised by high levels of anxiety and bodily arousal.
Gregory et al. (2006)
This is another support study for anxiety (and depression) as a cause of insomnia.
Aim- to investigate the relationship between high levels of anxiety and depression that arise from family conflict, and the later development of schizophrenia.
Procedure:
He carried out a longitudinal study of children in New Zealand from birth in 1972 until 2006.
Findings:
The level of family conflict experienced from the age 9-15 was significantly correlated with the frequency if insomnia at age 18
Limitations:
Methodological issues- relatively small group to be studying the effects of so many variables on.
The study was correlational therefore cause and effect relationships cannot be determined
Strength:
Ethical issues- consent from parents to observe child from birth, consent from child after age of 16 to be observed.
They were given right to withdraw
Chronotype
A second area where personality and sleep patterns overlap. This is mainly genetic
Chronotype - a personality type defined by the time at which a person is more alert. They could be morning larks or night owls.
The difference between these types is genetic and based on the circadian rhythms of the sleep wake cycle.
A night owl trying to be a morning lark or vice versa would mean they are fighting against their in built tendency which could lead to insomnia.
Insomnia involves neurotransmitters and is believed to occur due to malfunction in the sleep control system.
Support:
Kerkof and Van Dongen found that circadian rhythms in morning larks is around 2 hours ahead of night owls.
Narcolepsy
Narcolepsy is a chronic sleep disorder, affecting 1 in 2000 people.
It is characterised by 4 major symptoms:
Extreme day time sleepiness with frequent short episodes of sleep throughout the day.
Cataplexy- sudden loss of muscle tone while awake, leading to collapse. Some may have several attacks a day and it can be caused by any type of emotional arousal.
Hypnagogic hallucinations- dreams that occur while awake, during the transitional period between sleeping and waking up.
Sleep paralysis- inability to move, often occurs when falling asleep or waking up
Symptoms of narcolepsy reflect the intrusion of the REM sleep phenomena into waking life.
Narcolepsy is linked to problems with sleep systems in the hypothalamus using the neurochemical orexin (a neurotransmitter).
REM as an explanation of narcolepsy
AO1:
An explanation of narcolepsy is that is it caused by a malfunction in the system that regulates REM sleep.
During the day narcoleptics often experience intrusions of the REM sleep in the form of hallucinations and they have abnormal patterns of REM sleep at night.
Support/AO3:
Dement and Kleitman (1957) discovered the staged of sleep and found that during REM sleep our body becomes paralyzed and we dream. This could explain the symptom of cataplexy as the loss of muscle tone is similar to sleep paralysis.
Genetics/ loss of orexin as an explanation of narcolepsy
AO1:
Researchers have found a link between narcolepsy and orexin, a neurotransmitter that regulates alertness/wakefulness.
There are typically 10,000 to 20,000 orexin-producing cells in the hypothalamus, however in many narcoleptics a significant amount of these cells is missing, resulting in low levels of orexin.
AO3:
Lin et al (1999) found that dogs diagnosed with narcolepsy had a mutation in a gene which regulates brain receptors for orexin.
Without receptors orexin cannot function and this was believed to be the cause of narcolepsy in humans.
This study may not be generalizable to humans.
Thannickal, Moore and Niehuis (2000) found that orexin-producing cells in the hypothalamus were drastically reduced in narcoleptics
