By Izzy, Jade, Victoria, Harry and Lauren

The Disorder A rare, long term brain disorder that causes a person to fall asleep at inappropriate times because the brain is unable to regulate sleeping and waking patterns normally It is estimated that the condition affects roughly people in the UK Symptoms often begin during adolescence The symptoms include excessive daytime drowsiness, sleep attacks, loss of muscle control and muscle weakness

The Theory Narcolepsy is caused by a deficit of the neurotransmitter hypocretin, which regulates arousal, wakefulness and appetite. This is caused by variations on chromosome 6. These variations increase the risk of the immune system attacking neurones in the hypothalamus that produce hypocretin. It is possible that in some cases this auto immune response is triggered by flu vaccinations. Other risk factors include hormonal changes, major psychological stress or a change in sleeping patterns. Also, there is a form called secondary narcolepsy which is a result of an underlying condition such as a head injury, brain tumour or multiple sclerosis.

Research Studies Thannickal et al- found people with narcolepsy have less cells that produce hypocretin in their brains. This supports the theory that there is a link between narcolepsy and hypocretin. Sakurai- people with narcolepsy have low levels of hypocretin. This supports the theory because people who have reduced numbers of hypocretin often have narcolepsy. Vogel- REM occurs at the onset of sleep in people with narcolepsy, whereas REM usually occurs later in the sleep cycle with normal people, suggesting faulty REM mechanisms. This research adds a new interpretation to the theory and suggests there is a link between REM and narcolepsy. Mingot (2009) – Flu vaccination against H1N (Pandemrix) in Finland triggered narcolepsy in some children (1/16,000). This supports the theory as it suggests that the auto-immune response is caused by a flu vaccination. University of Tokyo – 79% increase of Narcolepsy in Japanese people because of a genetic link – Possibility of genetic link.

Evaluation Points The theory is considered reductionist The genetic variation on chromosome 6 causes a decrease in hypocretin production Overlooks role of possible cultural or environmental triggers, for example, stress However this may be positive as we can improve our understanding of narcolepsy to a specific area with scientific investigation This can lead to useful practical applications. Antidepressants are used to help prevent hallucinations and stimulants are used to keep the sufferer awake during the day. However these lead to side effects such as headaches, nausea and insomnia.

Quiz Time! 1) Which neurotransmitter in deficit causes narcolepsy? 2) What part of the brain is this neurotransmitter found? 3) What environmental factors increase the risk of an auto immune response? 4) How many children in Finland had narcolepsy due to the flu vaccination in Mingot’s study? 5) What percentage increase did the university of Tokyo find between Japanese people and narcolepsy? 6) At what stage does REM occur in narcoleptic patients (earlier or later) than normal people? 7) What was the link Sakurai found between narcolepsy and hypocretin levels? 8) What are the practical applications that have arisen from the research? 9) What type of medication are narcoleptic patients given? 10) What are the side effects caused by this medication?