SUDEP (Sudden Unexpected Death in Epilepsy)

People with epilepsy in general have an increased risk of premature death.  At times this is due to the underlying condition causing their epilepsy, or from injuries incurred during a seizure, or from a convulsive seizure that continues for a prolonged period without stopping (status epilepticus).(1, 2)  Another important cause is termed ‘sudden unexpected death in epilepsy’ or ‘SUDEP’.  This can be defined as a sudden, unexpected death in a person with epilepsy, with or without evidence for a seizure preceding the death, in which there is no evidence of other disease, injury, or drowning that caused the death.(3)


Overall, the risk of SUDEP among people with epilepsy is about 1 in 1,000 each year. But that risk varies considerably, depending on several factors of which these seem most important:(4-6)

  • The risk is greatest among people with convulsive seizures (tonic-clonic seizures with either focal or generalized onset) that are frequent or not well controlled. 
  • The majority of SUDEP is unwitnessed and it occurs most often at night or during sleep.


There may be several causes of SUDEP and more research is needed.(5)  While full recovery is expected following the vast majority of seizures, when SUDEP does occur, it appears to follow convulsive seizures in most instances.   The disruption of respiratory functions and sometimes heart rhythm, both known to occur during seizures, may play a role.  Similarly, certain genetic factors, or even co-existing conditions such as sleep apnea might sometimes be involved.  And in some SUDEP cases, the person is found face down in bed and an inability to move to allow breathing during the unconscious period following a seizure might be suspected.(7)


Optimizing seizure control—especially of tonic-clonic seizures—is the most important measure to reduce the risk of SUDEP. This requires steadfast adherence to medication prescriptions for epilepsy.  If seizures continue, improving control may require further consultations with expert neurologists about the need for medication adjustments or changes, or possibly surgery or other options.  Lifestyle factors should not be ignored, as these may sometimes affect seizure control; measures that may help include avoiding excessive use of alcohol or other drugs, and avoiding sleep deprivation or irregular sleep patterns.(5) Finally, although more research is needed, among some persons who remain at especially high risk, night-time or sleeping supervision by room companions or monitoring devices may be considered.(8)


  1. Levira F, Thurman DJ, Sander JW, Hauser WA, Hesdorffer DC, Masanja H, et al. Premature mortality of epilepsy in low- and middle-income countries: A systematic review from the Mortality Task Force of the International League Against Epilepsy. Epilepsia. 2017;58(1):6-16.
  2. Thurman DJ, Logroscino G, Beghi E, Hauser WA, Hesdorffer DC, Newton CR, et al. The burden of premature mortality of epilepsy in high-income countries: A systematic review from the Mortality Task Force of the International League Against Epilepsy. Epilepsia. 2017;58(1):17-26.f
  3. Nashef L, So EL, Ryvlin P, Tomson T. Unifying the definitions of sudden unexpected death in epilepsy. Epilepsia. 2012;53(2):227-33.
  4. Thurman DJ, Hesdorffer DC, French JA. Sudden unexpected death in epilepsy: assessing the public health burden. Epilepsia. 2014;55(10):1479-85.
  5. Shankar R, Donner EJ, McLean B, Nashef L, Tomson T. Sudden unexpected death in epilepsy (SUDEP): what every neurologist should know. Epileptic Disord. 2017;19(1):1-9.
  6. Watkins L, Shankar R, Sander JW. Identifying and mitigating Sudden Unexpected Death in Epilepsy (SUDEP) risk factors. Expert rev. 2018;18(4):265-74.
  7. Sveinsson O, Andersson T, Carlsson S, Tomson T. Circumstances of SUDEP: A nationwide population-based case series. Epilepsia. 2018;59(5):1074-82.
  8. Maguire M, Jackson C, Marson A, Nevitt S. Treatments to prevent Sudden Unexpected Death in Epilepsy (SUDEP). Cochrane Database of Systematic Reviews 2016. 2016(7): Art. No.: CD01179.

Other resources of interest