Epilepsy is a medical condition that produces seizures affecting a variety of mental and physical functions. It is also called a seizure disorder. When a person has two or more unprovoked seizures, they are considered to have epilepsy. Seizures happen when clusters of nerve cells in the brain signal abnormally, which may briefly alter a person's consciousness, movements or actions.
According to the Centers for Disease Control and Prevention, epilepsy affects 2.2 million Americans. The Institute of Medicine, in their recent report "Epilepsy Across the Spectrum," says "the 2.2 million prevalence estimate is most accurately viewed as approximating a midpoint in a wide potential range of 1.3 million to 2.8 million people with epilepsy."
Epilepsy affects 65 million people worldwide.
*Sources: From Epilepsy Foundation, http://www.epilepsyfoundation.org/aboutepilepsy/index.cfm