The abnormality may be caused by one of the many chemicals that control the brain's electrical functions. The abnormality may be in the way that cells of the brain, called neurons , have arranged themselves during growth or after an unrecognized injury to the brain. The abnormality may be a combination of both. Because there are a variety of abnormalities that cause epilepsy, seizures can take different forms from person to person. For example, some seizures do not involve the entire body, some do not cause a loss of consciousness, some do not involve movement, and some are triggered by specific events, such as reading or flashing lights.
Physicians have, therefore, divided epilepsy into several distinct sub-types.
More recent studies show that a person's chances of developing epilepsy are two to four times higher if there is a blood relative with epilepsy. This number increases as the number of relatives with epilepsy increases. As in most common diseases, both genes and environment play a role in epilepsy. We have already mentioned some of the environmental causes, such as trauma and drugs. The electrical system demands a great deal of energy.