What Is Epilepsy?


Epilepsy is the group name for the neurological disorders that cause seizures. Epileptic seizures happen because of unnecessary and uncontrolled electrical activity in the brain.  The electrical activity between the neurons (cells in our brains that carry the signals) controls our body.1,2

For example, part of the brain will send a signal to move the arm, and the electrical signals will be carried from the brain to the arm and the arm will move. In an epileptic seizure, however, erratic and uncontrolled electrical signals will cause the body to respond in an uncontrolled fashion. Our body is a machine and, the brain is our processor. When the processor surges with unnecessary electrical power, it will cause problems for the rest of the machine.

Epilepsy usually starts in childhood or with old age. It is a lifelong condition. 70% of those with epilepsy can manage their condition with medication and a healthy lifestyle.2 Unfortunately, no aspect of epilepsy is straightforward, parts of this article may look complicated at first, especially the symptoms, but we have simplified each aspect of it here.

Causes of epilepsy

All epilepsy attacks cause seizures but not all seizures are associated with epilepsy. While around 25% of seizures are said to be associated with epilepsy, there are a lot of other conditions that are associated with seizures like febrile seizures and seizures that are due to infection or stroke.1

Structural abnormalities in the brain, infections, certain medications, metabolic conditions (like dehydration or low blood sugar) and stress can all cause seizures.1

Signs and symptoms of epilepsy

The first and most important symptom of epilepsy is seizures. There are various types of seizures and because different parts of the brain control different parts of the body, seizures will affect everyone differently, depending on which part of the brain is affected.

International League Against Epilepsy, classifies seizures into three main groups: 

  • Focal
  • Generalised 
  • Unclassified

This classification is based on clinical observation and Electroencephalography (EEG).3

Focal seizures 

The human brain is made up of 2 hemispheres and 8 lobes. Hemispheres are the left and right sides of the brain. Each hemisphere is made of 4 lobes, frontal, temporal, parietal and occipital lobes. Each lobe controls different segments or functions of the human body. 

A seizure is classified as focal when it originates and affects only one part of the brain. For example, someone having a seizure in the occipital lobe, which is the part responsible for vision, may have visual hallucinations.3

Focal seizures are subdivided into three sections. Simple partial seizures are focal seizures when the consciousness of the affected individual is not impaired but they may experience motor and sensory symptoms. Simple partial seizures are short-lived, usually lasting between 60 and 120 seconds, and are vastly subjective. The affected area can be different for everyone with varied sizes., The seizures can be very subtle and hard to notice. Depending on the affected area, someone going through a simple partial seizure may have, short-lived sensations like falling, nausea, entered senses (for example loss of smell or increased taste) or feelings of deja vu. The consciousness of the person is not affected and is usually remembered in detail. Simple partial seizures can also happen during sleep.3

Complex partial seizures are similar to simple partial seizures but will involve impaired consciousness. A complex partial seizure may start as a simple partial seizure then evolve into consciousness involvement or start directly with impaired consciousness. impaired consciousness does not mean full loss of consciousness.3

Lastly, either type of focal seizure may also evolve into a generalised seizure.3

Generalised seizures

Generalised seizures are caused by electrical impairment in a large area of the brain. Symptoms may vary for each individual and may include stiff muscles, loss of consciousness, loss of muscle tone, jerking movements in the extremities, loss of bladder control and loss of control over speech.3

Generalised seizures are subdivided into six types: 

  1. Absence seizures
    1. Absence seizures (also known as petit mal seizures) cause you to go through unexpected intervals of unawareness as if the consciousness is shutting down and restarting again. They may look blank and return to the activity they were doing before the seizure started without realising what happened. During the seizure, they may also make small movements such as finger rubbing, chewing or lip smacking. Absent seizures are more common amongst children compared to adults, most commonly seen between the ages of 4 and 14. Diagnosis of absent seizures may be difficult as the seizure itself does not affect the rest of the body too much. For example, a child going through an absent seizure may just look like they are daydreaming. This type of seizure may also cause problems in school as these blank episodes may interfere with learning and social development.3
  2. Myoclonic seizures
    1. Myoclonic seizures are the type of seizure characterised by a short jerking or twitching of the muscles. They may go unnoticed as it will only last a second. Myoclonic seizures are generally caused by other problems such as but not limited to brain injuries, brain tumours, stroke, drug abuse or abnormal blood sugar levels.3
  3. Clonic seizures
    1. Clonic seizures are similar to myoclonic seizures as they result in repeated relaxing and stiffening of muscles. As with the similarity it can be difficult to distinguish between these two seizure types.3
  4. Tonic seizures
    1. Tonic seizures are described when part of the body is stiff or tense due to increased muscle tone. They usually happen during sleep and last only about 20 seconds. It is closely associated with Lennox-Gastaut Syndrome.
  5. Generalised tonic-clonic seizures
    1. Generalised tonic-clonic seizures are the most common type of seizures in people with epilepsy and are the result of tonic and clonic muscle contractions alternating. This type of seizure is described as a grand mal seizure. These seizures start abruptly and last between one to three minutes. Generalised tonic-clonic seizures are followed by an altered state of consciousness as the person involved may be unresponsive or sleeping which may then turn into a state of confusion.3
  6. Atonic seizures
    1. Atonic seizures result in reduced muscle tone in contrast with tonic seizures. They are also known as drop seizures as the libs suddenly go limp with reduced muscle control. They are short-lived and last around 15 seconds.3

Management and treatment for epilepsy

Although there’s no cure for epilepsy, it can be managed, meaning the seizures can be kept under control with daily medication. Anticonvulsant medications are the first-line treatment for epilepsy. There are different anticonvulsant medications available for the management of epilepsy and the choice of medication is made following factors such as type of seizure, other health problems and their age and lifestyle. Initial treatment will start with a single medication, in half the cases this is enough but for the other half second or third medication may be added to the regimen. It is worth noting however that in about 30% of the people with epilepsy, seizures will continue despite anticonvulsant treatment.2,3


How is epilepsy diagnosed?

Epilepsy diagnosis will be made by a  neurologist. As types of seizures can vary, having a definite diagnosis of epilepsy is not a straightforward procedure. First doctor will ask the patient questions about the seizures and their general health to determine underlying health conditions. 

An EEG will be used to check for unusual electrical activity in the brain. During the EEG test, sensors will be attached to the patient's head to read the electrical differences in brain activities.

Magnetic resonance imaging (MRI) may also be used to check underlying conditions in the brain, such as brain tumours are other types of neurological damage.

How can I prevent epilepsy?

In most cases, epilepsy cannot be prevented but there can be efforts made during childhood to reduce head injuries to prevent underlying conditions from forming.

Who is at risk of epilepsy?

Epilepsy is more common in the developing world and in populations with low income. In the developing world children and young adults are at risk, mostly due to high infection rates and higher number of head injuries. In the developed world, however, it is more common in older people.

How common is epilepsy?

While 10% of people have at least one epileptic seizure, it actively affects 1% of the world population. Overall epilepsy affects 1% of young adults and 3% of people over the age of 75. According to the World Health Organisation, 80% of those with epilepsy are from developing countries or low-income populations.

When should I see a doctor?

You should see your GP if you have experienced a seizure.  As discussed above, a seizure might happen in different ways and it will not be the same for everyone. Although having one seizure does not necessarily mean having epilepsy, it should be checked by a healthcare professional to find the underlying cause.

Seizures may also be an emergency. If the person is having their first seizure and has not resolved after 5 minutes and has a problem breathing or they may or already have injured themselves, you must seek urgent medical care.


Epilepsy is a very common condition that affects 1% of the world population, and it is characterised by unusual electrical activity in the brain that affects the function of the body. Various causes can result in epileptic seizures. You must speak with your doctor if you have any concerns about your health. Diagnosis of epilepsy is generally done by a neurologist with the use of an EEG to help spot problems in your brain.  Epilepsy is a lifelong condition but it can be managed with medication and a healthy lifestyle.


  1. Fisher RS, Acevedo C, Arzimanoglou A, Bogacz A, Cross JH, Elger CE, et al. ILAE Official Report: A practical clinical definition of epilepsy. Epilepsia [Internet]. 2014 [cited 2023 Jul 23]; 55(4):475–82. Available from: https://onlinelibrary.wiley.com/doi/10.1111/epi.12550.
  2. Ghosh S, Sinha JK, Khan T, Devaraju KS, Singh P, Vaibhav K, et al. Pharmacological and Therapeutic Approaches in the Treatment of Epilepsy. Biomedicines [Internet]. 2021 [cited 2023 Jul 23]; 9(5):470. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146518/.
  3. Fisher RS, Cross JH, French JA, Higurashi N, Hirsch E, Jansen FE, et al. Operational classification of seizure types by the International League Against Epilepsy: Position Paper of the ILAE Commission for Classification and Terminology. Epilepsia [Internet]. 2017 [cited 2023 Jul 23]; 58(4):522–30. Available from: https://onlinelibrary.wiley.com/doi/10.1111/epi.13670.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Kutal Mete Tekin

MRes, Bioengineering, Imperial College London

Kutal trained as a medical doctor in Istanbul before moving to London for this research masters at Imperial College London. He works as a part time medical interpreter with the NHS. His written work can also be seen in the motor sports sector as he has been a freelance sports writer and and editor since 2016.

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