What Causes Narcolepsy?

Most people who have narcolepsy have low levels of hypocretin. This is a chemical in the brain that helps control levels of wakefulness. What causes these low hypocretin levels isn't well understood.

Researchers think that certain factors may work together to cause a lack of hypocretin. These factors may include:

• Heredity. Some people may inherit a gene that affects hypocretin. Up to 10 percent of people who have narcolepsy report having a relative with the same symptoms.
• Infections.
• Brain injuries due to conditions such as brain tumors or strokes.
• Contact with toxins, such as pesticides.
• Autoimmune disorders. These are conditions in which the body's immune system attacks the body's healthy cells. An example of an autoimmune disorder is rheumatoid arthritis.

Heredity alone doesn't cause narcolepsy. You also must have at least one other factor, such as one of those listed above, to develop narcolepsy.