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Discuss explanations for insomnia and/or narcolepsy. (8 marks + 16 marks)
Explanations of narcolepsy are in majority biological. Scientists have discovered that narcoleptics
often are lacking in hypocretin which is a chemical in the brain that control sleep and wakefulness. A
lack of this chemical may explain the sudden attacks of sleep.
Sakurai (2007) highlighted how there are about 10,000-20,000 hypocretin-producing cells in a
normal hypothalamus, but people with narcolepsy have a significantly lower amount, resulting in low
levels of the neurotransmitter hypocretin which may cause narcolepsy.
There is much support for this explanation. For example, narcoleptic dogs have been shown to have a
genetic mutation which disrupts them processing hypocretin. Therefore, although narcolepsy is
genetic in dogs (although not in humans) the link between a genetic mutation and hypocretin
suggests that this chemical might be the key to unlocking the cause of narcolepsy in humans.
Nishino (2000) applied the findings from narcoleptic dogs and confirmed them in humans, for
instance it was confirmed that human narcoleptics had lowered levels of hypocretin than normal in
their celebrospinal fluid. Furthermore, the DSM 5 has stated that narcolepsy is a disorder of
hypocretin and that this can be used to diagnose narcolepsy.
Although, this research highlights a correlation between hypocretin and narcolepsy, it does not
establish a cause and effect between the two variables, for instance low hypocretin could be a
consequence of narcolepsy. This would suggest that narcolepsy can still be diagnosed using this
chemical but not necessarily explained. Furthermore, there are questions surrounding the causes of
the low levels of hypocretin. For example, this is genetic in dogs but the evidence has not supported
this in humans.
It is more likely that the lower levels of hypocretin could be due to brain injury, diet, stress or the
result of autoimmune attacks, thus making research into hypocretin low in internal validity.
On the other hand, researchers have found that narcolepsy might be linked to a malfunction of the
neural mechanisms controlling REM sleep; this can thereby explain some of the symptoms of
narcolepsy such as cataplexy, which is a loss of muscle tone.
Narcoleptics experience intrusions of REM type sleep as hallucinations when awake, and at night
have abnormal REM sleep. Therefore an explanation for narcolepsy is that it is caused by a
malfunction in the system that regulates REM.
Vogel (1960) supports this theory as he observed REM at the onset of sleep in a narcoleptic patient,
whereas REM usually occurs later in the sleep cycle, to suggest faulty REM mechanisms.
However despite this evidence, general research support for this theory is not particularly
convincing. Vogel's research is ungeneralisable to the wider public because he found this using a
small sample which could be prone to individual differences causing the disorder.
Instead, narcolepsy is much more common in later life, not as children, when individuals experience
less REM. This suggests it's an adult condition triggered by possibly other genetic factors coupled
alongside lifespan changes, such as hormonal changes.
Alternatively, insomnia may be explained through being genetically inherited because usually a family
history of persistent difficulties with sleep indicates that the disorder may be passed on. The gene
may prevent the neural mechanisms that control sleep from operating.
Another explanation of restlessness is poor sleep hygiene. Habits, behaviours and activities that
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inhibit sleep such as watching TV before going to bed or studying in the bedroom can restrict the
onset and disturb the quality of sleep. For example, watching TV activates the SCN in the pineal gland
because the light from the LCD screens act as exogenous zeitgebers which stimulates the brain to tell
us that it's daytime and we shouldn't be sleeping.
There is research support to suggest that insomnia is an inherited sleep disorder.…read more