The two main symptoms of narcolepsy are feeling sleepy all the time and episodes of cataplexy, which is a loss of muscular control, during the day. Such episodes seem to be triggered by various forms of emotional arousal such as stress, anger, fear or amusement.
Other symptoms include hallucinations and sleep paralysis, which are experienced when falling asleep or waking up, and interruption of night time sleep by frequent waking.
Narcolepsy usually begins in adolescence or early adulthood and continues throughout life. It is thought that there are 1 in every 2000 sufferers, although this may be an underestimate as many go undiagnosed due to the fact that they only have minor symptoms.
In the 1960’s the view was held that it was linked to a malfunction in the system that regulates REM sleep, which explained some of the symptoms such as cataplexy which accompanies REM sleep and the intrusion of hallucinations into daytime sleep.
This was first proposed after Vogel (1960) observed REM sleep at the onset of a narcoleptic patient. This explanation was further supported by recordings of neuron activity in the brainstems of narcoleptic dogs. Research showed that cataplexy is linked to the…