=> What is SUDEP?

SUDEP refers to the sudden and unexpected death of a healthy person with epilepsy where no cause of death is found at autopsy. ***************************************** SUDEP definition per Nashef 1997: “Sudden, unexpected, witnessed or unwitnessed, nontraumatic and nondrowning 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 toxicologic or anatomic cause for death.” [1]

=> What causes SUDEP?

The cause of SUDEP is not yet known. As it usually occurs at night, during sleep, and is most often unwitnessed, understanding exactly what happens during the last moments of life is difficult. There is often, but not always, evidence of a seizure (particularly a generalized tonic-clonic seizure) before death.

It is unlikely that a single cause will explain all SUDEP deaths. Advances in research are identifying critical risk factors and a number of potential mechanisms for SUDEP.

Researchers are investigating problems with:

  • breathing
  • heart rhythm; and
  • brain function

as possible causes of SUDEP.

During seizures there is often a change in breathing and heart rhythm. In most people with epilepsy, this is not dangerous. Sometimes, a more serious drop in blood oxygen levels or changes in heart rhythm may occur. Seizures may also affect the brain’s control of breathing and heart function.

Researchers are exploring genetic links between seizures and heart rhythm abnormalities. Further research is urgently needed to reveal these possible causes of death and to help people with epilepsy understand how to lower their risk of SUDEP.

=> What are the risk factors for SUDEP?

The strongest risk factor for SUDEP is the occurrence and frequency of generalized tonic-clonic (sometimes known as 'grand mal') seizures (GTCS).

People with 3 or more GTCS per year have a 15-fold increased risk of SUDEP. The more uncontrolled or frequent these seizures are, the higher the risk of SUDEP. Seizure freedom, particularly freedom from GTCS, is strongly associated with decreased SUDEP risk. [2]

Oher risk factors are being investigated. To help minimize your risk, it is important to discuss SUDEP with your healthcare provider and remember that low risk is not the same as no risk. There are things you can do.

=> Can SUDEP be prevented?

The best way to reduce the risk of SUDEP is to have as few seizures as possible.

To help achieve this:

  • Keep regular appointments with your healthcare provider, even if your seizures seem well controlled. It is important to regularly review your SUDEP risk and the steps you take to minimise that.
  • Take your seizure medications regularly and reliably. If you have concerns about side effects, it is important not to make changes to your medications without talking to your healthcare provider.
  • Identify and avoid triggers for seizures (such as lack of sleep, drinking too much alcohol or using recreational drugs).
  • Ask your healthcare provider about other epilepsy treatments (such as surgery) when medications are not enough to control seizures.
  • Make sure those around you know that you have epilepsy and what they can do to help you during and after your seizure.
  • Stay up to date with the latest

=> How common is SUDEP?

Research studies estimate loss due to SUDEP each year is:

  • 1 in 1,000 people with epilepsy [2, 3];
  • about 1 in 100 people with frequent epileptic convulsions that are poorly controlled with medications.
However, the true number of deaths due to SUDEP is unknown but most likely higher than these estimates. This is mainly because:
  • the identification of SUDEP is poor, due to lack of awareness;
  • anatomic findings (eg tongue/lip bite) implicating epilepsy as a cause or contributor to the death are commonly lacking;
  • autopsies may not be conducted, which are vital for making the diagnosis by exclusion required for accurate determination of SUDEP; and
  • there are challenges to, and inconsistencies in, the investigation and certification/recording of these deaths.

Brochures: for download, in English/French/Spanish

Video: Purple Day's Cassidy Megan explains SUDEP


[1]  Nashef, L (1997). Sudden unexpected death in epilepsy: terminology and definitions. Epilepsia 1997;38(Suppl 11):6-8.

[2]  Harden, C et al. (2017). Practice guideline summary: Sudden unexpected death in epilepsy incidence rates and risk factors. Neurology Apr 2017;88(17)1674-1680.

[3] Keller, AE et al. (2018). Incidence of sudden unexpected death in epilepsy in children is similar to adults. Neurology Jun 2018, 10.1212/ WNL.0000000000005762