Sudden Unexpected Death in Epilepsy (SUDEP)

5 Things You Should Know about SUDEP

#1 SUDEP is not well understood.

Father and son walking.

SUDEP stands for Sudden Unexpected Death in Epilepsy. SUDEP refers to deaths in people with epilepsy that are not from injury, drowning, or other known causes.1 Most, but not all, cases of SUDEP happen during or right after a seizure.1

Researchers do not understand the exact cause of SUDEP, but these are possible reasons it happens:2-4

  • Breathing changes: A seizure may cause a person to have pauses in breathing. If these pauses last too long, they can reduce the oxygen in the blood to a dangerous level. Also, if a person’s airway gets blocked during a seizure, that can lead to suffocation.
  • Heart rhythm changes: Rarely, a seizure may cause a dangerous heart rhythm or cardiac arrest.
  • Other causes and mixed causes: SUDEP may happen because of a combination of breathing trouble and abnormal heart rhythm.

People with epilepsy are at increased risk of SUDEP if they have:

  • Uncontrolled or frequent seizures.1,3,4
  • Generalized convulsive (what used to be called tonic-clonic or grand mal) seizures.1,3,4

Other things that may increase someone’s risk of SUDEP include:

  • Seizures that start at a young age.3,4
  • Many years of living with epilepsy.3
  • Missing doses of medicine.3,4
  • Drinking alcohol.1

#2 SUDEP is rare, but traumatic for families.

Woman taking a pill.

If you have epilepsy, it’s important to take your seizure medicine as prescribed. The chance of SUDEP is higher in people who have frequent seizures.1

Researchers estimate that for every 1,000 people with epilepsy, at least 1 person may die from SUDEP each year.5 This means that each year in the United States, there are about 3,000 deaths due to SUDEP. But counting SUDEP cases is hard because SUDEP is not always included on death certificates.5

SUDEP occurs more often in people ages 21 to 40 compared to other age groups.5 Because SUDEP can happen unexpectedly to people who are so young, it can be very shocking for families and loved ones.

#3 Managing seizures may help.

Research has shown that controlling seizures may lower the chance of SUDEP. If you have epilepsy, the most important way to do this is to take your seizure medicine as prescribed.1

Other steps that might help lower the chance of SUDEP1:

If you are taking medicine and still having seizures, talk to your doctor about changing your medicine or other things that might help. If seizures continue, consider seeing an epilepsy specialist. Learn how to find specialty careexternal icon from the Epilepsy Foundation.

#4 Support is available.

Losing a loved one to SUDEP can be especially hard because it’s so unexpected. The Epilepsy Foundation’s SUDEP Instituteexternal icon provides information and support to families who are grieving.

Parents of children with epilepsy can learn more about SUDEP in children, including tips on how to talk to your child’s doctor.

#5 Research continues.

CDC supports research to help us understand SUDEP better. Together with the National Institutes of Health, CDC funds the Sudden Death in the Young Case Registryexternal icon. The goals of this project are to count the number of cases and to understand the causes of death in infants, children, and young adults who die suddenly and unexpectedly — including from SUDEP.6 Researchers will use this information to recommend how to prevent these types of death in the future.

The Epilepsy Foundation and partners also support other SUDEP researchexternal icon.

More Information
  1. Devinsky O. Sudden unexpected death in epilepsy. New Engl J Med. 2011;365:1801-11.
  2. So EL. What is known about the mechanisms underlying SUDEP? Epilepsia. 2008;49(Suppl. 9):93–98.
  3. Tomson T, Nashef L, Ryvlin P. Sudden unexpected death in epilepsy: current knowledge and future directions. Lancet Neurol. 2008;7(11):1021-31.
  4. Nei M, Hays R. Sudden unexpected death in epilepsy. Curr Neurol Neurosci Rep. 2010;10(4):319-26.
  5. Thurman DJ, Hesdorffer DC, French JA. Sudden unexpected death in epilepsy: Assessing the public health burden. Epilepsia. 2014;55(10):1479-85.
  6. Burns K, Bienemann L, Camperlengo L, Cottengim C, Covington TM, Dykstra H et al. The Sudden Death in the Young Case Registry: Collaborating to understand and reduce mortality. Pediatrics. 2017; 139(3):e20162757.
Page last reviewed: May 28, 2021, 10:00 AM