What causes epilepsy? Key factors explained

What causes epileptic seizures? What exactly are the causes of epilepsy? Answering these questions is important to better understand these major health issues and decide what the most effective treatments would be in each individual case¹. An epileptic seizure is an uncontrolled, anomalous electric discharge from the brain that changes the communication between nerve cells; this may alter one’s movement, sensation, behaviour or state of consciousness². Its various symptoms might include: muscle contractions, trembling, tingling, altered sight or hearing, involuntary movement, mental symptoms and confusion, loss of consciousness or other disorders³. A sole epileptic seizure does not necessarily imply an epilepsy diagnosis in and of itself – and this is another of the primary myths to be debunked on this disease. Rather, epilepsy is defined as a disorder with a risk of recurrent seizures, which means that some will have had a single seizure but testing will show a high risk of another event⁴. Let’s have a look at what causes epilepsy. 

What causes epileptic seizures? 

A seizure does not always mean someone has epilepsy. An infection, skull injury, the effects of some drugs, as well as other medical conditions may be the cause⁵. In such instances what we have are acute symptomatic or provoked epileptic seizures, which arise close on the heels of trauma, infections or toxic reactions to drugs⁶. If there is no other damage to the brain, this would be asingle symptomatic seizure. If there is some residual damage to the brain this can cause emote symptomatic seizures and where tests may suggest the risk of further seizures could be high⁶. When someone has recurring unprovoked seizures, the diagnosis is epilepsy^4,6. 

What causes epilepsy? 

Epilepsy is a chronic disease that involves onset of unprovoked epileptic seizures⁵. What are the causes of epilepsy? For most epilepsy patients its exact underlying causes are unknown⁴. For other patients, different factors may have contributed to developing this disease⁴. Here are the main ones. 

Genetic factors 

Some genetic factors were identified quite some time ago⁷. Epilepsy is genetic when it results from an alteration in one or more genes - even genes not inherited from one’s family but appearing spontaneously in the individual8. Scientists have found specific mutations in a minority of cases, including those in the SCN1A, SCN2A, GABRA1 and SYNGAP1 genes (although there are others), associated with developing epilepsy⁷. Other outside (environmental) factors can also contribute to the development of epilepsy⁸.  

Structural factors 

Anything which damages or distorts brain structure or function can, increase the risk of developing epileptic seizures⁹. Generally, these changes show up on biomedical imaging exams such as the CT or magnetic resonance imaging (MRI)⁹. They include head trauma, brain tumours, stroke, specific congenital diseases which change brain structure, and other medical conditions⁹. 

Infections 

Sometimes seizures can be caused by scarring associated with specific infectious diseases that affect the brain, like meningitis, encephalitis and neurocysticercosis⁴, a parasitic disease common in parts of the Southern Hemisphere. This is caused by the parasite Taenia solium, which is the most common cause of acquired epilepsy¹⁰.  

Metabolic and immune-related causes  

In some cases, epilepsy is even autoimmune, where the immune system mistakenly attacks nerve cells¹³. This is what occurs in autoimmune encephalitis for example¹³. Rarely, in an acute setting seizures may be due to metabolic disorders which include: a drop in or lack of oxygen in tissues, electrolyte imbalance (electrolytes are minerals in our bodily fluids¹¹), a prolonged drop in blood sugar or rise in blood ammonia levels¹².

Ultimately, there are different factors that can lead to epileptic seizures, whether they be infectious, structural, genetic, metabolic or autoimmune⁴. Knowing what causes epileptic seizures can help your doctor obtain a more accurate diagnosis and determine the best treatment.

References  

1. National Institute of Neurological Disorder and Stroke (NINDS – NIH), “Epilepsy and seizures - Treating epilepsy and seizures”
2. NINDS (NIH), Epilepsy and seizures - What are epilepsy and seizures?” https://www.ninds.nih.gov/health-information/disorders/epilepsy-and-seizures#toc-how-are-epilepsy-and-seizures-diagnosed-and-treated-
3. Epilepsy Foundation, “What happens during a seizure? – Common Symptoms during a seizure”, 
4. World Health Organization (WHO), “Epilepsy”, 7 February 2024
5. Cure Epilepsy, “What is a seizure? – What causes a seizure?”
6. Huff J.S., Murr N.I., “Seizure”. [Updated 2023 Feb 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430765/
7. Dwivedi R., Kaushik M., Tripathi M., Dada R., Tiwari P., “Unraveling the genetic basis of epilepsy: Recent advances and implications for diagnosis and treatment”. Brain Research., Volume 1843, 2024, 149120, ISSN 0006-8993, https://doi.org/10.1016/j.brainres.2024.149120.
8. Epilepsy Foundation, “Genetic causes of epilepsy”
9. Epilepsy Foundation, “Structural causes of epilepsy”
10. Del Brutto O.H., “Neurocysticercosis”. The Neurohospitalist. 2014 Oct;4(4):205-12. doi: 10.1177/1941874414533351. PMID: 25360206; PMCID: PMC4212415.
11. Istituto Superiore di Sanità (ISS), “Elettroliti (analisi cliniche)”, 15 December 2021
12. ISS, “Epilessia”, 30 January 2019
13. Mayo Clinic, “Autoimmune Epilepsy”, 21 December 2024