Epilepsy is a disorder that disrupts the transmission of electrical signals inside the brain. Although it may be assumed that epilepsy always causes episodes of uncontrolled movements and loss of consciousness, the condition is actually variable. Seizures are often subtle, causing strange sensations, emotions and behavior. Some people with epilepsy simply stare blankly for a few seconds when having a seizure, while others have full-fledged convulsions.

About one in 100 people in the United States has experienced an unprovoked seizure at some point in life, but a solitary seizure doesn't mean you have epilepsy. Many people experience one seizure and then never have another one. But after you've had two seizures, the chance that you'll have additional seizures increases dramatically. At least two unprovoked seizures are required for a diagnosis of epilepsy. The onset of epilepsy is most common during childhood and after age 65, but the condition can occur at any age. Treatments may leave you free of seizures, or at least reduce their frequency and intensity. Many children with epilepsy even outgrow the condition with age.

Several types of epilepsy have been linked to defective genes that regulate how brain cells communicate with each other, but it appears that abnormalities in any of several hundred genes may play a role in the development of epilepsy. Genetic inheritance plays only a partial role in epilepsy, perhaps by making a person more susceptible to environmental factors that cause seizures.
In many cases the onset of epilepsy can be traced to an accident, disease or other medical trauma that injures your brain or deprives it of oxygen: head injuries are responsible for many cases of epilepsy. However, epilepsy has no identifiable cause in about half of all affected people.

Most people with epilepsy can become seizure-free by using a single anti-epileptic drug. Others can decrease the frequency and intensity of their seizures with medication. Finding the right medication and dosage can be complex: your doctor likely will first prescribe a single drug at a relatively low dosage, and may increase the dosage gradually until your seizures are well controlled. If anti-epileptic medications don't provide satisfactory results, your doctor may suggest other treatment options such as surgery, vagus nerve stimulation or a ketogenic diet.