Narcolepsy is a sleep disorder that is often under-recognized and underdiagnosed. About 1 in every 2,000 people in North America and Europe suffer from this syndrome, which tends to be a lifelong phenomenon. The symptoms of narcolepsy can be terrifying at first and frustrating even after someone becomes used to them, but they never produce any serious illness. People with narcolepsy are usually healthy in all other respects. They have exactly the same natural life expectancy as those without it. No physical abnormality or tissue damage has ever been linked to this condition, either as a cause or as a consequence.
Men and women are equally likely to suffer from narcolepsy, and there is an increased risk for children of parents with the condition. It usually first appears in the teenage years, but it can come on at almost any age. Often the symptoms appear one by one, but in people aged over 20 it's more likely that several symptoms will appear at once. Symptoms may change over time in an individual, but there's no general tendency for them to get worse or better with age.