Experiencing a seizure, or seeing someone have one, can feel frightening. It can happen suddenly, sometimes with no clear warning, and the person may seem very different from one moment to the next.
Some seizures involve shaking and loss of consciousness. Others are less obvious. A person may stare blankly, become confused, collapse, black out, notice strange sensations, or have a gap in memory afterwards. This is one reason seizures can be difficult to recognise, especially when they do not look like the dramatic episodes people often associate with epilepsy.
A first seizure does not automatically mean someone has epilepsy. Seizures can happen for many reasons, and medical assessment helps work out what may have caused the episode and whether it is likely to happen again.
What happens in the brain during a seizure?
A seizure happens when there is a sudden burst of abnormal electrical activity in the brain. This temporarily disrupts how nerve cells communicate with each other.
Because the brain controls movement, awareness, sensation, behaviour and consciousness, seizures can look very different depending on which part of the brain is affected.
Some people have jerking or shaking movements. Others lose awareness, collapse, stare into space, feel confused, experience unusual smells or tastes, or have a sudden change in behaviour. Some seizures last only a few seconds. Others continue for several minutes.
Not all seizures look dramatic from the outside. Sometimes the main sign is that the person seems absent, confused or unable to respond normally for a short time.
Why can a seizure happen unexpectedly?
A seizure is a symptom, not a diagnosis by itself. It means the brain has had a sudden episode of abnormal electrical activity, but there may be different reasons for this.
Some seizures are linked to epilepsy. Others may happen because of a head injury, high fever, low blood sugar, alcohol or drug withdrawal, severe illness, infection affecting the brain, stroke or another neurological condition.
For some people, the first seizure happens with no obvious trigger. That can feel especially unsettling, but it is also why assessment matters. Doctors may need to look for possible causes and decide whether the episode was isolated or whether there is a higher chance of it happening again.
What can make a seizure more likely?
Some situations can increase the likelihood of a seizure in people who are susceptible to them.
Lack of sleep, excess alcohol, recreational drugs, certain medicines, illness, fever, infection and major physical stress can all lower the brain’s seizure threshold. Flashing lights can trigger seizures in a small number of people, although this is not the case for most.
A trigger does not always mean someone has epilepsy. It may simply mean the brain was more vulnerable at that moment. Identifying possible triggers can still be useful because it may help reduce the chance of another episode.
What might someone feel like after a seizure?
After a seizure, many people go through a recovery period. This is sometimes called the postictal phase.
During this time, the person may feel confused, sleepy, exhausted, emotional or disorientated. They may have a headache, sore muscles, difficulty concentrating or memory gaps around what happened.
This can last minutes or sometimes several hours, depending on the type of seizure and how long it lasted.
Even if someone appears to recover fully, a first seizure should still be assessed by a doctor. The recovery afterwards does not always tell you why the seizure happened.
Why does a first seizure need medical assessment?
A first seizure needs medical assessment because doctors need to understand what caused it and whether further tests are needed.
This may include blood tests to check for problems such as low blood sugar or changes in salts and minerals in the blood. Brain imaging, such as an MRI or CT scan, may be used to look for structural causes. An EEG may be arranged to record electrical activity in the brain.
Doctors will also ask about what happened before, during and after the episode. A witness account can be very helpful, especially if the person does not remember the seizure. If someone safely recorded a video of the episode, this can sometimes help clinicians understand what type of event occurred.
A diagnosis is usually based on the whole picture, not one test alone.
What should you do if someone has a seizure?
Most seizures stop on their own within a few minutes. The main aim is to keep the person safe until the seizure passes.
Stay with them and try to remain calm. Time the seizure if you can. Move nearby objects out of the way so they do not injure themselves. If possible, cushion their head and loosen anything tight around their neck.
If they are not awake and aware, turn them onto their side once it is safe to do so. This helps keep the airway clear.
Do not restrain their movements, put anything in their mouth or try to wake them during the seizure. These actions can cause harm and do not stop the seizure.
Stay with them afterwards until they are awake, alert and breathing normally.
When is a seizure an emergency?
Call emergency services if the seizure lasts longer than 5 minutes, if another seizure starts before the person has fully recovered, or if breathing does not return to normal afterwards.
You should also seek urgent help if the person is injured, the seizure happens in water, the person does not return to their usual state, or recovery seems unusually slow.
Urgent medical assessment is also important if it is a first seizure, if the person is pregnant, if they have diabetes, or if there is prolonged confusion afterwards.
If you are unsure, it is safer to seek urgent advice.
When should you speak to a doctor?
You should speak to a doctor after any first seizure, unexplained blackout, collapse or episode where someone becomes confused, unresponsive or behaves unusually and cannot remember what happened.
You should also get medical advice if episodes are brief but recurring, or if someone else has noticed unusual movements, staring episodes or changes in awareness.
A doctor can review the pattern of symptoms, look for possible triggers or medical causes, and decide whether referral to a neurologist or further investigations are needed.
A first seizure should always be taken seriously
Seizures happen because of sudden abnormal electrical activity in the brain, but they do not all look the same. Some involve shaking and collapse. Others are much more subtle.
A first seizure should always be medically assessed, even if the person seems to recover fully afterwards. This does not mean assuming epilepsy or the worst possible cause. It means checking what happened, looking for treatable causes and understanding whether there is a chance it could happen again.
Knowing what to do during a seizure, when to call emergency services and when to seek medical advice can make the situation safer and less frightening for everyone involved.
Find the right specialist for you. Doctify uses verified reviews so you can make the best decision for your healthcare.
Medically Reviewed
Last reviewed on 26/05/2026
