Understanding Epilepsy

Epilepsy is a group of brain disorders that cause seizures. Important things to know:

  • Epilepsy can affect anyone at any age, but most people are diagnosed before age 2 or after age 65.
  • Early diagnosis and treatment can control seizures and prevent potentially life-threatening complications.
  • Medications can stop seizures in about 70% of patients.

What is epilepsy?

Epilepsy is a complex group of neurologic (brain and nervous system) disorders. Surges of electrical activity in the brain cause repeated seizures. These bursts of uncontrolled, unusual brain cell activity can affect your:

  • Attention
  • Behavior
  • Movements
  • Consciousness

Epilepsy and seizures can vary from mild to severe. Episodes can range from blank stares lasting a few seconds to unconsciousness and convulsions lasting several minutes.

A person is diagnosed with epilepsy after at least two seizures that have no other identifiable cause. Someone can also be diagnosed after one seizure if factors show a high likelihood of repeat seizures.

Who gets epilepsy?

Epilepsy can affect anyone. About 3 million adults and 450,000 children in the U.S. live with epilepsy, according to the Centers for Disease Control and Prevention. That’s about one in 100 people.

Key facts about epilepsy include:

  • Frequency: Epilepsy is the fourth most common neurologic condition in the U.S., after migraine, stroke and Alzheimer’s disease.
  • Onset: Epilepsy can begin at any age. It most often begins in babies and young children, or in adults 60 and older.
  • Gender: Men are slightly more likely than women to develop epilepsy.
  • Race and ethnicity: Epilepsy affects people of all races and ethnicities around the world. Some groups have a slightly higher or lower risk, but the differences are small.
  • Family history: Genetic defects related to epilepsy can be passed down in families. Certain types of epilepsy are more likely to have a genetic cause. Experts are still researching possible genetic causes. Learn about genetic testing at OHSU.

Early diagnosis

If you have a seizure, especially more than one, it’s important to see your doctor. Early diagnosis is the key to controlling seizures. Seizures can cause potentially life-threatening complications, such as:

  • Falls
  • Risk of drowning
  • Car accidents
  • Problems during pregnancy
  • Emotional disorders such as anxiety and depression
  • Status epilepticus — a long seizure (five minutes or more) or a series of seizures without regaining consciousness
  • Sudden unexpected death in epilepsy (SUDEP)

Learn how we diagnose epilepsy at the OHSU Comprehensive Epilepsy Center.

Signs and symptoms of epilepsy

Symptoms vary based on the type of seizure and the part of the brain affected. Symptoms may have other causes so it's important to see a doctor. 

Common signs and symptoms include:

  • Uncontrolled twitches or jerks, sometimes with passing out
  • Rigid muscles
  • Briefly staring or "blanking out," then going on as if nothing happened
  • Sudden unusual feelings or perceptions (auras), such as fear or deja vu, or unusual smells or tastes
  • Suddenly feeling confused or disoriented
  • Repeated movements such as lip smacking, chewing, blinking, rubbing hands, walking in circles or picking at clothes

What causes epilepsy?

Not everyone with risk factors will develop epilepsy, and people can develop epilepsy without any risk factors. In addition, doctors can’t identify the cause in about half of cases.

When the cause is known, the most common factors are:

  • Brain infections such as meningitis or viral encephalitis
  • Head trauma, such as a concussion or more traumatic brain injury
  • Stroke or blocked blood supply to part of the brain
  • A brain tumor

Other causes and risk factors include:

  • Neurologic disorders such as autism; or Alzheimer’s disease or another type of dementia
  • Injury to an unborn baby, such as brain damage from lack of oxygen, poor nutrition, or an injury or infection affecting the mother
  • An inherited genetic defect
  • Seizures in childhood, especially long-lasting ones

Find out more about OHSU genetic testing and counseling for neurologic disorders at our Neuro Genetics Clinic.

Epilepsy triggers

Not everyone with epilepsy has triggers — things that can set off a seizure. For those who do, triggers can include:

  • Sleep deprivation
  • Alcohol or drug use
  • Video games, flashing lights, or bold, contrasting patterns
  • Missed medications
  • Stress
  • Menstruation or other hormonal changes
  • Illnesses or fevers

Types of epilepsy

Epilepsy includes several syndromes identified by type of seizure and symptoms. Common epilepsy syndromes include:

Some epilepsy syndromes involve focal seizures, which affect only part of the brain:

  • Benign rolandic epilepsy: Thought to be inherited, this syndrome makes up about 15% of epilepsy cases in children. Seizures typically stop by age 15. Seizures can last up to two minutes, and children remain conscious.
  • Panayiotopoulos syndrome: This childhood epilepsy starts between ages 3 and 10. Seizures can last 20 to 60 minutes and often occur during sleep. Seizures stop after about three years.
  • Rasmussen’s syndrome: The immune system attacks brain cells and causes inflammation that can lead to brain damage. People often need surgery because medications can’t control the seizures well.

  • Doose syndrome: Also known as myoclonic astatic epilepsy, this type starts in early childhood. Medications might not manage it effectively, but dietary therapy can work well.
  • Juvenile absence epilepsy: JAE usually begins between ages 10 and 17. It is a lifelong condition requiring medication. JAE can cause attention, concentration and memory issues. Treatment can improve symptoms.
  • Juvenile myoclonic epilepsy: JME is the most common generalized epilepsy syndrome that starts in mid- to late childhood, from ages 5 to 16. Medications usually control this inherited syndrome well.

  • Infantile spasms, also known as epileptic spasms or West syndrome: This syndrome begins in infants 4 to 6 months old. It requires early treatment to avoid issues with learning, thinking, behavior and development.
  • Lennox-Gastaut syndrome: This syndrome usually starts in childhood and lasts into adulthood. It is difficult to manage with medications and can result in problems with thinking and behavior.

  • Frontal lobe epilepsy: This syndrome may be inherited, and its seizures can usually be controlled with medications. It can affect various body parts, depending on where in the frontal lobe the seizures start.
  • Temporal lobe epilepsy: This type is the most common syndrome related to focal (partial) seizures. Because the temporal lobe controls many vital functions, seizures in this part of the brain can dramatically affect quality of life.

Types of seizures

The world’s main scientific organization dedicated to epilepsy, the International League Against Epilepsy, updated its classification of seizures in 2025. The classification has four categories:

  • Focal: These seizures start on one side or part of the brain.
  • Generalized: These seizures involve both sides of the brain.
  • Unknown whether focal or generalized
  • Unclassified

Learn more

For patients

Location

OHSU Comprehensive Epilepsy Center
Mark O. Hatfield Research Center, 13th Floor
3250 S.W. Sam Jackson Park Road
Portland, OR 97239

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