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Autism and Epilepsy

By Professor Tony Attwood and Dr. Michelle Garnett

We know there is a link between autism and epilepsy. Studies have confirmed that up to 8% of intellectually able autistic children and over 20% of autistic children with an intellectual ability also have epilepsy (Amiet et al., 2008; Liu et al., 2022; Tuchman, 2017). There is also a correlation between the frequency of epileptic seizures and the degree of intellectual disability (Liu et al., 2022; Pacheva et al., 2019). Epilepsy can affect both speaking and non-speaking autistic individuals.

In this blog, we describe the various types of epilepsy that can be experienced by an autistic child or adult, strategies for seizure management, including medication and the behavioural and psychological effects of having epilepsy.

Onset of epilepsy

There are bimodal peaks for the onset of epilepsy, in the general and autistic population, namely infancy and puberty (Gillberg & Steffenberg, 1987). There is also an association between epilepsy and syndromic autism, which is autism associated with a medical condition such as Tuberous Sclerosis, Neurofibromatosis, mitochondrial disorders and Landau-Kleffner syndrome. We also recognise that epilepsy in childhood persists into adulthood in up to 80% of autistic individuals, with remission in about 16%.

What is epilepsy?

The term epilepsy is derived from the Greek word meaning ‘take hold’ or ‘seize’, hence the English term, seizure. During an epileptic seizure, nerve cells are caught in a reverberating cycle of repetitive firing. Excessive neuronal firing continues until excitatory neurotransmission is exhausted or the inhibitory networks extinguish it. Neurons that control muscles cause the muscles to contract, and neurons associated with other functions can lead to unusual sensations and altered levels of alertness and consciousness. We are all prone to seizures. It depends on our individual seizure threshold.

A range of circumstances can lower the seizure threshold, such as high body temperature (fever), low blood sugar, stress, lack of sleep, and antipsychotic medication. Hormonal changes during adolescence, particularly for girls, can profoundly affect seizure activity. Sometimes, seizurs are triggered by specific stimuli such as flashing lights and sudden noises, and for certain types of epilepsy, seizures occur more often during sleep. Seizures may also occur in clusters.
Epilepsy is not a disease or mental illness, and a diagnosis of epilepsy requires two seizures that occur at least 24 hours apart. A seizure usually lasts seconds to minutes. An electroencephalogram, or EEG, can record excessive and abnormal neuronal activity in the cortex of the brain, which can be part of the diagnostic process for epilepsy.

Types of epilepsy

Generalised Seizures affect the entire brain at once; these include tonic-clonic, myoclonic, atonic, and absences.

Partial seizures can be called focal or local and start from one part of the brain. Simple partial seizures (consciousness remains normal), complex partial seizures (consciousness altered), and the transition from focal to generalised seizures.

All types of seizures can occur in autistic individuals, but complex partial are the most common seizure type (Pacheva et al. (2019).

Generalised seizures

Tonic-clonic seizure

There are three stages in a tonic-clonic seizure.

  1. Aura: a preceding sensory experience which can be a particular smell, the sensation of tingling in hands, or the cognitive sensation of déjà vu (a feeling that something new has been experienced before) or jamai vu (the erroneous belief of having never experienced something that has been experienced). The recognition of experiencing an aura can be valuable in providing time to move to circumstances to avoid injury during the seizure, such as moving away from a table edge or going into the recovery position.
  2. Ictal stage this is is the seizure event. Usually, it starts with a loss of consciousness, followed by the Tonic stage, which involves stiffening of the extremities, and then the Clionic stage, which involves twitching movements, rhythmic jerks, clenching of teeth, and possible loss of bladder control. The person often turns blue as breathing stops in the tonic phase. The ictal stage usually lasts up to 5 minutes.
  3. Postictal state includes sleepiness, muscle weakness, confusion, and difficulty speaking. Often, the person does not remember what happened during this time. There can be abnormal behaviour, including psychosis (delusions and hallucinations), after a seizure, which is relatively common, occurring in 6-10% of people (Wheless, 2009). The person is likely to feel drowsy and depressed afterwards. A non-speaking autistic young man typed, “The seizures are really exhausting, and I need to sleep for hours afterwards”.

A tonic-clonic seizure used to be called a ‘grand mal’.

Strategies for managing a tonic-clonic seizure

  1. Please remember to stay calm. This is not easy for a parent whose son or daughter has lost consciousness.
  2. Then, check safety from physical injury, such as protecting the person’s head, perhaps with an item of clothing, and clearing the adjacent area.
  3. Do not try to stop the movements.
  4. Protect the airways, but do not put anything in the person’s mouth.
  5. Ensure the person is in the recovery position.
  6. Stay with the person until they recover.
  7. Call for medical assistance if the seizure lasts more than ten minutes.
  8. Prolonged or recurring seizures that last more than 20 minutes are called Status Epilepticus, and parents and carers may be trained in the administration of medication to end this expression of epilepsy.

Myoclonic seizures

These are brief, startle-like jerks and are often associated with drowsy states. A myoclonic seizure can occur when waking up.
Atonic seizures
They are sometimes called a ‘drop attack’ with a sudden loss of muscle tone and risk of falling and injury with no attempt to protect oneself. The person may wear a protective helmet if they frequently experience an atonic seizure.

Absence seizures

These are 3-30-second staring spells that used to be called a ‘petit mal’. There is a sudden halt in activity and appearing to ‘freeze’. The person’s eyes may roll up, stare or flicker with usually no confusion afterwards. Absence seizures are more likely in children than adults.

Partial seizures

There are simple partial seizures with abnormal sensations, such as seeing spots or feeling fear, and Complex partial seizures with a well-defined aura followed by a confused ‘trance’. Partial seizures used to be called Temporal or Frontal Lobe seizures.

A partial seizure may start with automatisms, such as involuntary movements such as eye blinking and ‘fluttering’ and actions such as lip smacking, fumbling, and finger-picking movements. These can be signs that a partial seizure is imminent.

The seizure can lead to experiencing intense feelings of fear or panic and include complicated motor automatisms, such as vigorous movements, kicking, hitting, and being aggressive to others or deliberately injuring themselves.

As clinicians, we have supported many non-speaking autistic clients who have been referred due to extremely agitated behaviour. Our analysis of the antecedents and potential function of the agitated behaviour may not show any consistent or distinct patterns of motivation or function from the individual’s perspective, current and past circumstances, or quality of support. The extremely agitated behaviour appears to occur quickly and is unresponsive to behaviour management strategies. Those who know the person may say that this behaviour is out of character. When extremely agitated, they cannot be distracted or encouraged to end the agitation, which can involve the destruction of property or considerable self-harm. We have recognised that the sudden intensity and ineffectiveness of appropriate response strategies could indicate that the autistic person is experiencing a partial seizure, and we recommend an assessment by a neurologist.

Unfortunately, a partial seizure is often not recorded on an EEG. The false negative rate can be up to 70%, although a repeat EEG reduces this to 30%. Thus, an EEG recording in the normal range does not automatically rule out experiencing partial seizures. However, the neurologist will explore the nature of the agitated behaviour to identify any preceding automatisms, and it can be helpful for parents or carers to record videos of the agitated behaviour on a mobile phone to indicate the degree of consciousness. We have found that medication for epilepsy can be very effective in reducing the frequency, intensity and duration of agitated behaviour due to a partial seizure.


Anti-epileptic medication is divided into narrow-spectrum medications, such as carbamazepine, and broad-spectrum medications, such as lamotrigine, based on the seizure type. The primary effect of anticonvulsant medication is on the inhibitory neurotransmitter GABA. Medication is usually daily and has no significant effect on cognitive functioning.

A study of autistic research participants’ responses to antiepileptic medication found that 58% were seizure-free on medication, and a further 27% had more than a 50% reduction of seizures. There was therapeutic resistance in 15%, and consideration may be given to prescribing more than one antiepileptic medication (Pacheva et al., 2019).

It can take up to a month for the medication to have a positive effect, and regular blood tests will need to be undertaken to confirm whether the anticonvulsant is within the therapeutic range. There is a concept of a ‘window of opportunity’—not too little or too much medication. Medication may be discontinued for children who have been seizure-free for about two years and about five years for adults.

Psychological effects of epilepsy

Having seizures witnessed by family members, friends and the general public can lead to low self-esteem, social withdrawal and internalising problems such as depression. The autistic person may need psychological support from family and perhaps a psychologist.

There is also the effect on parents, as witnessing a seizure can be frightening, being unsure when the seizure will end, and worrying about what they can do during and after the seizure. Parents need to be compassionate but not overprotective. They may also be concerned about the long-term effects of epilepsy but can be reassured that repeated seizures do not cause brain damage.

Where to from here?

On Friday, the 28th of June, Michelle and Tony will present a full-day course on Understanding and Supporting Non-speaking Autism. The course will equip participants with an understanding of life as experienced by a non-speaking autistic person, the reasons for specific behavioural and emotional reactions and the creation of an individualised plan to enhance the quality of life and well-being.
Participants in the course will learn practical strategies to encourage speech, the value of alternative and augmentative communication systems, how to acquire new abilities and coping mechanisms for accommodating changes in routines and expectations, sensory sensitivity, and social engagement, conditions that co-occur with autism including epilepsy and how to express and regulate intense emotions constructively.



Amiet et al. (2008). Epilepsy in autism is associated with intellectual disability and gender. Biological Psychiatry 64, 577–582.

Gillberg and Steffenberg (1987). Outcomes and prognostic factors in infantile autism and similar conditions Journal of Autism and Developmental

Liu et al. (2022). Prevalence of epilepsy in autism spectrum disorders: A systematic review and meta-analysis Autism 26.

Panayiotopoulos CP (2010). A clinical guide to epileptic syndromes and their treatment based on the ILAE classifications and practice parameter guidelines (Rev. 2nd ed.). London: Springer.

Pacheva et al. (2019). Epilepsy in Children with Autism Spectrum Disorder. children 6, 15; doi: 10.3390/children6020015

Tuchman (2017) What is the relationship between Autism Spectrum Disorders and Epilepsy? Seminars in Pediatric Neurology

Tuchman and Rapin (2002). Epilepsy in Autism. Lancet Neurol. 2002;1(6)
Wheless (2009). Advanced therapy in epilepsy. Shelton, Conn.: People’s Medical Pub. House. p. 443.