Despite being first described in 1880 by Gelineau, narcolepsy remains an underdiagnosed cause of excessive daytime sleepiness.
The typical episodes of irresistable sleep are due to abnormal intrusion of REM sleep into wakefullness.
- in narcolepsy there is a disruption in the usual patterns of non-rapid-eye-movement (NREM) sleep and rapid-eye-movement (REM), or 'dreaming', sleep. As a consequence, this causes difficulty in staying asleep and in staying awake and bouts of irresistible daytime sleepiness under unusual circumstances (e.g. while eating or talking) (1)
- other characteristic features (these represent intrusions of REM sleep into
- a sudden loss of muscle tone - this feature is provoked by emotional stimuli and which can make the person fall
- sleep paralysis
- unpleasant generalised paralysis - this occurs just before, or while, falling asleep or on waking
- vivid hallucinations on falling asleep (hypnagogic) or on waking (hypnopompic)
Narcolepsy has a strong genetic aetiology.
There are effective pharmacological treatments.
There are estimated to be around 1 in 3,000 people with narcolepsy, which typically starts in adolescence or early adult life (1).
- Drug and Therapeutics Bulletin (2004); 42(7): 52-6.