Disorders

What is epilepsy?

Reviewed June 2026 by David C. Spencer, MD, FAAN

Definition: Epilepsy is a long-term neurological disorder defined by recurrent unprovoked seizures, meaning the seizures happen repeatedly and aren’t caused by some other issue. Seizures happen when there’s a sudden surge of electrical activity in the brain.

Your brain cells are constantly communicating by sending electrical signals to each other. Seizures, however, are caused when brain cells fire in an uncontrolled way. You can be diagnosed with epilepsy if you’ve had two unprovoked seizures, or if you’ve had one seizure with a high risk of another.

Epilepsy is one of the most common serious neurological disorders and can affect people of all ages. It can affect physical health, thinking, emotions, and daily life. Around the world, millions of people are living with epilepsy. Many are able to manage it successfully with the right care and support.

What are the symptoms of epilepsy?

The main symptom of epilepsy is repeated seizures, but seizures may not look the same for everyone.

Depending on the type of seizure, symptoms may include:

  • Brief loss of awareness or consciousness
  • Sudden changes in movement, such as jerking or stiffness
  • Repeated automatic movements, like lip-smacking or hand rubbing
  • Staring spells or pauses in activity
  • Changes in senses, such as sight, sound, or taste
  • Changes in mood or thinking, including anxiety or depression

There may be warning signs before a seizure starts, such as unusual smells or a feeling of déjà vu.

Types of seizures

  • Focal-onset seizures start in one area of the brain and may or may not affect consciousness
  • Generalized-onset seizures affect both sides of the brain and usually affect consciousness
  • Unknown-onset seizures are seizures with no clear starting point

Seizures can also be described based on whether a person maintains awareness (aware or impaired) and whether involuntary movement is involved.

Doctors use these descriptions to better understand what’s happening, choose treatment, and help predict what may happen over time.

What are the causes and risk factors of epilepsy?

Epilepsy happens when the brain’s normal signaling balance is disrupted.

It may be linked to a wide variety of conditions that affect the brain, including:

  • Stroke
  • Dementia
  • Brain injuries (including at birth)
  • Brain infections
  • Developmental conditions
  • Brain tumors
  • Blood vessel abnormalities
  • Genetic factors

For some people, the exact cause is not fully identified.

How is epilepsy diagnosed?

Neurologists may diagnose epilepsy after:

  • Two unprovoked seizures
  • One unprovoked seizure with a high risk of another

A seizure is “unprovoked” if it wasn’t caused by some other specific issue, like fever, low blood sugar, or a head injury. 

Diagnosis often includes a detailed history of seizures, an EEG to measure brain activity, and brain imaging such as MRI or CT scans

These tests help neurologists and other doctors confirm a diagnosis, understand seizure risk, and guide treatment decisions.

What treatments are available for epilepsy?

Treatment depends on the type of seizures and each person’s needs. Options for some people may include medicines to prevent seizures, surgery, or specialized diets.

Medications
Anti-seizure medications are the starting point for treatment and are effective in controlling seizures in about 7 in 10 people with epilepsy. However, some people may continue to have seizures despite taking anti-seizure medications.

When seizures are not controlled by medication
Some people have drug-resistant epilepsy, meaning seizures continue despite trying at least two appropriate anti-seizure medications. Poorly controlled seizures can affect safety, health, and quality of life, but other treatment options may help.

Other treatment options
If medications are not effective enough, options may include:

  • Surgery to treat the area of the brain causing seizures.
  • Neurostimulation devices that target specific brain regions or brain networks involved in seizures. These devices include vagus nerve stimulation (VNS), responsive neurostimulation (RNS), and deep brain stimulation (DBS).
  • Following a ketogenic diet (especially for children).

With the right diagnosis and care, many people can reduce or control their seizures.

Caring for and navigating epilepsy

Explore practical tips, personal stories, and expert guidance for living well with epilepsy.

Frequently asked questions

What is the difference between epilepsy and seizures?

A seizure is a single event caused by abnormal brain activity. Epilepsy is a condition where seizures happen repeatedly over time.

Is epilepsy genetic or inherited?

Some types are linked to genetic changes. Other types can develop after an injury, illness, or other conditions that affect the brain. Often, the cause isn’t known.

What triggers seizures in someone with epilepsy?

Triggers vary from person to person, but may include:

  • Lack of sleep
  • Stress
  • Illness
  • Flashing lights
  • Missing doses of anti-seizure medication
Can you live a normal life with epilepsy?

Many people with epilepsy live full, active lives. With the right care and support, seizures can often be managed successfully.