Narcolepsy is a serious sleep disorder that disturbs night time sleep patterns (similar to insomnia) but in addition leaves the sufferer prone to the sudden onset of sleep at any moment. Although not dangerous in and of itself, it obviously poses problems with learning, working and using equipment which requires constant attention.
Narcoleptics are often refreshed by their sudden sleep, but in most cases the refreshment only lasts a few hours before the patient once again becomes too tired to stay awake. This cycle can occur several times a day. It is often accompanied by sleepwalking and related autosomnal disorders. In severe cases, the patient can be struck with sleep paralysis (the inability to move upon waking) or hallucinations. It is not uncommon for narcoleptics to also suffer from long bouts of insomnia.
The cause of narcolepsy is unknown, but it does appear to have a genetic component. In addition, recent research has pointed to antibodies being involved in the disease, which may later classify it as an autoimmune disorder.
Narcolepsy is both rare and difficult to diagnose. It is estimated that there are 50,000 diagnosed cases in the United States, and there are probably as many as 150,000 undiagnosed cases. In can only be properly and definitively diagnosed by observation of the patient in a sleep lab and noting differences in the patient's EEG.
Treatment is also difficult and must be tailored to each individual. Bringing the disease under control often takes several months of trial and error with drug therapies. Amphetamines and anti-depressants are both commonly used.