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Medically reviewed by Last updated on Jan 25, 2022.

What is Epilepsy?

Harvard Health Publishing

Epilepsy is a brain condition that causes repeated episodes of sudden, brief changes in the brain’s electrical activity. These changes cause various types of symptoms.

Epileptic episodes are called seizures or convulsions. During a seizure, brain cells fire uncontrollably at up to four times their normal rate. Seizures temporarily affect the way a person behaves, moves, thinks or feels.

There are two main types of seizures:

  • A generalized seizure involves the entire brain.
  • A focal (partial) seizure begins in one brain area. It affects only part of the brain. However, a focal seizure can turn into a generalized seizure.


There are two other much less common types of seizures:

  • A combined generalized and focal seizure
  • A seizure of unknown type

Many conditions can affect the brain and trigger epilepsy. These include:

  • Brain injury, either before or after birth
  • Brain tumors
  • Infections, especially meningitis and encephalitis
  • Genetic conditions
  • Abnormal blood vessels in the brain
  • Metabolic or chemical imbalance problems
  • Immune disorders
  • Lead poisoning

In most people with epilepsy, the specific cause is unknown.


The symptoms of epilepsy vary. They depend on how much of the brain is affected, and where the affected area is located.

Primary generalized seizures:

  • Generalized tonic-clonic seizure (grand mal seizure) — The person loses consciousness. He or she falls to the ground and temporarily stops breathing. All body muscles tense up at once for a short period. This is soon followed by a series of jerking movements. Some people also lose bowel or bladder control.

The seizure episode may last for a few minutes, during which a person is unconscious. When someone wakes up from a generalized tonic-clonic seizure, they are lethargic and confused. This usually lasts minutes, but it can last hours. There may be muscle soreness and a headache.

  • Absence seizure (petit mal seizure) — Loss of consciousness is so brief that the person usually doesn't change position. For a few seconds, the person may:
    • Have a blank stare
    • Blink rapidly
    • Make chewing movements
    • Move an arm or leg rhythmically.

This type of seizure usually begins in childhood or early adolescence.

Partial (focal) seizures:

  • Simple partial seizure —The person remains awake and aware. Symptoms vary depending on the brain area involved. They can include:
    • Jerking movements in one part of the body
    • An experience of abnormal smells, sounds, or changes in vision
    • Nausea
    • Emotional symptoms, such as unexplained fear or rage
  • Complex partial seizure — The person may seem to be aware, but is briefly unresponsive. There may be:
    • A blank stare
    • Chewing or lip-smacking
    • Repetitive movements of the hand
    • Unusual behaviors, like walking around a room and pulling books off a bookshelf, while not responding to what other people are saying

After the seizure, the person has no memory of the episode.

Status epilepticus —Occurs when a person has a generalized seizure that lasts long enough to raise the risk of death, or recurs without full return to consciousness.  Status epilepticus used to be defined by a generalized seizure that lasted 30 minutes or more. Today, it is defined by one of two features:

  • Seizure that lasts 5 minutes or more, or
  • Two or more seizures that occur without a complete recovery of consciousness between the seizures

Status epilepticus is a life-threatening medical emergency that requires immediate medical attention.


You may not have any seizure symptoms when you visit your doctor's office. For this reason, it is important to enlist the help of anyone who has witnessed your seizure. Ask that person to describe exactly what they saw: what happened at the start, what happened next. Write this description down for your doctor. This description will help your doctor determine the type of seizure you had. It will also help to decide on appropriate treatment.

Having a seizure does not mean that a person has epilepsy. For example, it's common for children to have seizures associated with fever. Most children who have them do not develop epilepsy.

Your doctor will diagnose epilepsy based on:

  • Your history
  • A thorough physical examination
  • A thorough neurological examination
  • The results of an electroencephalogram (EEG)

In many cases, your doctor will also order a computed tomography (CT) scan or magnetic resonance imaging (MRI) scan of the brain. Other types of brain scans also may be needed.

Your doctor may want to check whether your seizures are related to causes outside the brain. To do so, he or she may order basic lab tests. These can include blood tests, urinalysis and an electrocardiogram (EKG).

Expected Duration

Epilepsy can be a lifelong condition. But many people with a history of multiple seizures eventually will stop having seizures.

People who are younger when seizures start are more likely to stop having seizures. The same is true for people who have a normal neurological examination.

For most people with epilepsy, seizures can be controlled with medication.


The cause of most cases of epilepsy remains unknown. Therefore, there is no way to prevent the condition.  

However, there is very effective treatment for people with epilepsy that can reduce the number and severity of seizures. For many, control of epilepsy can prevent almost all seizures from occurring.

To help prevent epilepsy caused by head injury, you can:

  • Wear seat belts while driving.
  • Equip your car with air bags.
  • Wear an approved helmet while skating, riding a motorcycle or bicycling.
  • Use protective headgear for sports.

Anyone with an active seizure disorder should take precautions. These will minimize the risk of injury if a seizure should occur. For this reason, people with epilepsy are advised not to operate a motor vehicle for at least six months after the most recent seizure. The same applies to operating other dangerous machinery.

People with epilepsy should consider wearing some sort of medical identification that describes their condition. This will provide important information to emergency medical personnel.


In most cases, treatment begins with one of the many anti-epileptic medications. The type of medication used depends on the type of seizure being treated.

When medication fails to control a person's seizures, surgery may be considered. If the abnormal electrical activity that triggers each seizure is coming from one particular part of the brain, cutting out that part of the brain can stop the repeated seizures. Of course this kind of brain surgery can cause some permanent problems with brain function, depending on where in the brain the focus of the seizures is. For this reason, the risks of surgery have to be balanced against the benefits. The decision to perform surgery depends on many factors. These include:

  • Frequency and severity of seizures
  • Patient's risk of brain damage or other injury from frequent seizures
  • Effect on quality of life
  • Patient’s overall health
  • Likelihood that surgery will control seizure episodes

Status epilepticus is a life-threatening medical emergency. It is treated with medications given intravenously or rectally. Protective measures are also taken. These measures keep the person's airway open. And they help to prevent injury to the person's head and tongue.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

View more treatment options

When To Call A Professional

Call your doctor whenever you or anyone in your family experiences new symptoms suggestive of a seizure.  

Call for emergency help immediately if you suspect that someone with epilepsy has developed status epilepticus.


Most people with epilepsy can control their seizures with medication.

Some people have epilepsy that cannot be controlled with anti-epileptic drugs. Many of these cases can be treated with surgery.

Learn more about Epilepsy

Treatment options

Care guides

External resources

American Epilepsy Society

Epilepsy Foundation


Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.