helpline 01494 601 400
enquiries 01494 601 300


Sometimes a person with epilepsy dies during or following a seizure for no obvious reason. This Sudden Unexpected Death in Epilepsy (SUDEP) is uncommon and in some cases may be preventable.


For many people, epilepsy is a condition which can be well-managed and has little or no impact on their life. For others, ongoing seizures mean that epilepsy has a long-term impact on them and their ability to have a ‘normal life’. Like some other medical conditions, epilepsy can be a cause of death in some individuals, although this is not common.

There are more than half a million people with epilepsy in the UK. Around 600 people die each year due to Sudden unexpected death in epilepsy (or SUDEP). Although the percentage of the population who are affected by SUDEP is relatively low, every death due to SUDEP is thought to be potentially avoidable.

SUDEP is a research priority for Epilepsy Society, and researchers have made an important breakthrough in discovering that an individual’s genetic makeup may contribute to the risk of SUDEP.

SUDEP can be a difficult subject to talk about. It can be upsetting or worrying to think about. Knowing a little about SUDEP and the risks around having seizures might help you to work out what risks apply to you and how to reduce them so you can feel more in control.

Definition of SUDEP

The textbook definition of SUDEP is

the sudden, unexpected, witnessed or unwitnessed, non-traumatic, and non-drowning death in patients with epilepsy with or without evidence for a seizure, and excluding documented status epilepticus, in which postmortem examination does not reveal a structural or toxicological cause for death.

This means that SUDEP is when someone is believed to have died during or after a seizure where no other cause of death can be found.

Why does SUDEP happen?

The reasons for SUDEP are not clearly understood. As SUDEP is thought to happen either during or following a seizure, it is possible that it is due to a problem with the person’s heart or breathing during or following the seizure.

The risk factors around SUDEP

Although we don’t know for certain why it happens, there are some situations that are thought to make SUDEP more likely in certain people.

  • As SUDEP is thought to happen during or following a seizure, uncontrolled or poorly controlled seizures are a risk.
  • SUDEP is thought to be more likely in people with frequent seizures, particularly convulsive seizures, than in people with infrequent seizures.

It is worth remembering that the risk of SUDEP varies from one person to another but some of the risks around SUDEP can be reduced.

Reducing risk

As SUDEP is thought to be linked to seizures happening, getting the best seizure control possible is a positive way to reduce risks, including the risk of accident, injury and SUDEP.

Getting the best seizure control possible might include:

  • Take anti-epileptic drugs (AEDs) consistently (every day) and around the same time or times each day. This is sometimes referred to as ‘being adherent’ to medication. If you have difficulties taking your medication (for example, if you find it difficult to remember to take your medication), aids such as pill boxes (drug wallets) might be helpful. 
  • Keep a diary of when your seizures happen. This will help to show if there is a pattern to your seizures and whether any situations trigger your seizures (like being tired or stressed). It might also be useful to see how well medication is working to control your seizures. Download our free paper or electronic seizure diaries.
  • If you are still having seizures, having a review of your epilepsy and treatment with a neurologist or epilepsy nurse might be helpful. There may be changes to your treatment that would help to reduce the number of seizures you have.

SUDEP and sleep

SUDEP often happens when the person is asleep. If you have seizures during sleep, having a seizure alarm that alerts someone if you have a seizure, might be helpful. This means that help can be called to check on you at night.

Using safety or ‘anti-suffocation’ pillows, which have holes in them for ventilation means that if you are face down on the pillow during a seizure, you may be able to breathe more easily.

Find out more about alarms and safety aids.