There are many different types of seizures. This information is for people affected by or concerned about generalised seizure types. On this page we tell you about the most common generalised seizure types.
Use this page as a general guide and speak to a health professional for more information and support.
A generalised seizure (or generalised onset seizure) affects both sides of the brain from the start. It causes you to black out (lose consciousness). Sometimes, the period of unconsciousness is so short it may not even be noticed.
Before a generalised seizure, you may have unusual symptoms that could be a sign your seizure is starting. This warning is also known as an ‘aura’. It’s likely that this warning will happen at the beginning of the seizure in just one part of the brain, before it spreads to the whole brain. If you do get this warning, try to get into a safe place, even if that’s just sitting on the floor.
Seeing anyone have a seizure can be quite frightening. It can be especially worrying when the person having a seizure is a baby or child. But it’s important to remember that if they’re unconscious during generalised onset seizures, they will not be aware of what’s happening, and they usually recover quickly.
Tonic-clonic seizures used to be called grand mal seizures. They are the type most people recognise.
Tonic-clonic seizures are caused by abnormal electrical activity which affects the whole brain. This type of seizure usually comes with reduced awareness or a complete loss of consciousness.
The name ‘tonic-clonic’ describes the physical symptoms that occur during the two phases of the seizure – the tonic phase followed by the clonic phase. We describe each of these phases in the sections below.
A tonic-clonic seizure starts with the tonic phase. During this phase you may become stiff and fall to the ground. Sometimes you may bite your tongue, make a brief crying sound, and may become unconscious.
The tonic phase may last about ten to 20 seconds.
The clonic phase usually comes next after the tonic phase. During this phase, your arms or legs may begin to jerk. After a few minutes, the jerking slows and stops, and the muscles relax.
After the seizure, which usually lasts around one to three minutes, you might be drowsy, confused and agitated and take some time to return to normal. You may also have wet or pooed yourself or have bitten your tongue. Often, you will feel exhausted and need to sleep.
If a tonic-clonic seizure lasts for five minutes or more, this is called status epilepticus and needs emergency treatment. If you have repeated seizures (e.g. three or more in 24 hours), this also needs emergency treatment. Talk to your doctor about what exactly this means for you.
Find out more about emergency medication for seizures.
You told us what really helps when you're having a seizure, and we listened. This guidance is shaped by a powerful mix of lived experience and clinically informed expert advice, coming together to help others know what to do.
To help someone who is having a tonic-clonic (convulsive) seizure, follow these steps:
Call an ambulance if:
The person may have an emergency management or care plan. If they do, you should follow the instructions in their plan. Their plan may include giving them their prescribed emergency medication, but do not administer emergency medication unless you are trained to do so. If you have to call 999, stay on the line and follow the guidance of the call handler. Find out more about emergency medication.
Absence seizures often begin in childhood and do not usually continue into adulthood, although they do continue in some types of epilepsy.
There are two types of absence seizures – typical and atypical. We describe each of them in the sections below.
In typical absence seizures, you may do the following things:
These things can happen many times a day. Then, you will snap back, continue what you were doing before and be unaware of the seizure.
Often, other people might not even notice these episodes. If you’re at school, it's possible that staff may mistake absence seizures for not paying attention or daydreaming. This may happen if they do not know how seizures can affect children. Because of this, children with absence seizures may find it hard to learn and keep up at school because they miss information.
If you don’t believe your absence seizures are being taking seriously in class or they are impacting your learning, read up on the support you are entitled to. If you’re a parent or carer, you can also talk to the school if you’re worried about this.
Typical absence seizures are linked with clear changes in electroencephalogram (EEG) test results. Doctors will use EEG tests to help work out if you are having typical absence seizures.
Atypical absence seizures do not usually start or finish as quickly as typical absence seizures. They usually last longer, and you might have changes in your muscle tone that cause small movements, such as nodding your head slightly or chewing.
Sometimes, you may continue to respond to your surroundings during an atypical seizure. Atypical absence seizures are also often linked with other seizure types and learning disability.
You told us what really helps when you're having a seizure, and we listened. This guidance is shaped by a powerful mix of lived experience and clinically informed expert advice, coming together to help others know what to do.
To help someone who is having an absence seizure, follow these steps:
Call an ambulance if they’ve seriously injured themself.
Myoclonic seizures can be both generalised (affecting both sides of the brain) and focal seizure types (affecting one side).
You are usually awake during a myoclonic seizure – this can often happen just after waking or when you are tired before going to bed.
The name of this seizure describes what happens during this type of seizure:
During this type of seizure, you might also roll your eyes, blink, nod, make coughing sounds, or fall to the ground (if you’re standing).
Myoclonic seizures happen in a variety of epilepsy syndromes, such as juvenile myoclonic epilepsy syndrome.
You told us what really helps when you're having a seizure, and we listened. This guidance is shaped by a powerful mix of lived experience and clinically informed expert advice, coming together to help others know what to do.
Even though they only last a few seconds, a myoclonic seizure can be scary and confusing for both the person experiencing it and the person witnessing it. But you can help.
To help someone who is having a myoclonic seizure, follow these steps:
Call an ambulance if they’ve seriously injured themself, or if they have lots of seizures in a short space of time.
The person may have an emergency management or care plan. If they do, you should follow the instructions in their plan. Their plan may include giving them their prescribed emergency medication, but do not administer emergency medication unless you are trained to do so. If you have to call 999, stay on the line and follow the guidance of the call handler. Find out more about emergency medication.
Tonic seizures can be generalised (affecting both sides of the brain from the start) or focal (they start in one side of the brain).
The name ‘tonic’ means an ‘increase in tone or tightness’ of the muscles.
During a tonic seizure, the muscles in your chest, arms and legs may contract rapidly, causing your arms, legs and body to become stiff (rigid). Your back may also arch and your breathing may change. Changes to your breathing, may mean that your skin colour changes slightly, for example the skin around the mouth may look blue. This is because your lungs are getting less oxygen.
You might also lose consciousness and fall to the ground. Once the seizure has stopped, you regain consciousness and your muscle tone goes back to normal.
Seeing someone have a seizure can be very distressing but remember that they often do not last for very long. Tonic seizures are generally short (less than a minute) and the person will recover from them quickly.
People with Lennox-Gastaut syndrome are more likely to have this type of seizure.
To help someone who is having a tonic seizure, follow these steps:
Call an ambulance if:
The person may have an emergency management or care plan. If they do, you should follow the instructions in their plan. Their plan may include giving them their prescribed emergency medication, but do not administer emergency medication unless you are trained to do so. If you have to call 999, stay on the line and follow the guidance of the call handler. Find out more about emergency medication.
Atonic seizures can be generalised (affecting both sides of the brain from the start) or focal (they start in one side of the brain).
Atonic is the opposite of tonic, so during an atonic seizure muscle tone is reduced, which causes you to suddenly flop forward and fall to the ground. This is sometimes called a ‘drop attack’. In babies, atonic seizures most often appear as a ‘head drop’.
During an atonic seizure, you may lose consciousness for a short time. But you usually recover quickly.
If you are at risk of atonic seizures, or they happen often, you may need to wear protective headgear, such as a helmet. This is because of your risk of injury from falling or losing consciousness.
People who have other seizure types, such as tonic or myoclonic seizures, may also have atonic seizures.
You told us what really helps when you're having a seizure, and we listened. This guidance is shaped by a powerful mix of lived experience and clinically informed expert advice, coming together to help others know what to do.
Even though these seizures only last a few seconds, someone having one still needs your help.
To help someone who is having an atonic seizure, follow these steps:
Call an ambulance if they’ve seriously injured themself.
The person may have an emergency management or care plan. If they do, you should follow the instructions in their plan. Their plan may include giving them their prescribed emergency medication, but do not administer emergency medication unless you are trained to do so. If you have to call 999, stay on the line and follow the guidance of the call handler. Find out more about emergency medication.
Last reviewed July 2025.
Next review due July 2028.
If you would like to find out more about how we produce our information, or the sources of evidence we use, please contact us at healthinfo@youngepilepsy.org.uk
Discover what an epileptic seizure is, how to identify a seizure in babies and infants, and about non-epileptic seizures and episodes.
Learn about the differences between focal and generalised seizures and how to identify each.
Learn about epileptic seizures in babies and infants, including types and signs, from birth to one year old.
Get guidance on how to help someone having a seizure, including when to call an ambulance and helping babies and infants.
Learn about common seizure triggers in children and young people, including poor sleep, missed medication, and flickering lights.
Learn about status epilepticus, prolonged seizures, and emergency medication for managing seizures lasting more than five minutes.
Young Epilepsy’s information about nocturnal seizure monitors and other equipment, apps and services for parents of children with epilepsy.
Learn about common seizure triggers in children and young people, including poor sleep, missed medication, and flickering lights.
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