20-30%
Epilepsy prevalence in autism
Amiet et al., 2019 — meta-analysis
~40%
Epilepsy prevalence in autism with ID
Amiet et al., 2008; Viscidi et al., 2013
~1%
General population epilepsy prevalence
Epilepsy Ontario, 2024
20-60%
EEG abnormalities in autism (without clinical seizures)
Spence & Schneider, 2009 — Pediatric Research
A 2019 meta-analysis by Amiet et al. reported a pooled epilepsy prevalence of 21.4% in autistic individuals. Risk factors for epilepsy in autism include co-occurring intellectual disability (odds ratio 3.7), female sex, and regression in early development. The risk persists across the lifespan, with seizure onset occurring at any age.
Common seizure types in autistic individuals include focal seizures (which may be subtle and mistaken for stimming or inattention), absence seizures (brief staring episodes), and generalized tonic-clonic seizures. Subclinical epileptiform activity detected on EEG is also common in autistic individuals without clinical seizures, though the clinical significance of this finding remains debated.
Parents should watch for regression in skills, new onset of staring spells, unexplained falls, nighttime convulsive movements, or sudden behavioural deterioration — all potential indicators of seizure activity.
Anti-seizure medications (ASMs) are the primary treatment. In autistic individuals, medication selection must consider cognitive and behavioural side effects. Levetiracetam is frequently used as first-line because of its favourable cognitive profile, though it can exacerbate irritability in some autistic individuals. Valproate, lamotrigine, and clobazam are other commonly used options.
Ontario epilepsy resources include: the Epilepsy Program at SickKids (Toronto), the Epilepsy Monitoring Unit at McMaster Children's Hospital (Hamilton), London Health Sciences Centre's Epilepsy Program, and CHEO's Neurology Division (Ottawa). Epilepsy Ontario provides education, support groups, and navigation assistance across the province.
When epilepsy co-occurs with autism, intervention planning should account for seizure medication effects on attention and behaviour, seizure safety during therapy sessions, and the potential impact of uncontrolled seizures on developmental progress. Communicate seizure action plans to all therapists and educators involved in the child's care.
Amiet, C. et al.
Epilepsy in Autism is Associated with Intellectual Disability and Gender: Evidence from a Meta-Analysis. Biological Psychiatry, 2008; 64(7):577-582
Viscidi, E.W. et al.
Clinical Characteristics of Children with ASD and Co-Occurring Epilepsy. PLoS ONE, 2013; 8(7):e67797
Commitment to Accuracy: Our data is verified against official government reports (FAO, MCCSS), peer-reviewed scientific literature, and accessible public records. Last updated: March 24, 2026.
Verified Facts
1 in 50, According to the 2019 Canadian Health Survey on Children and Youth, about children and youth aged 1 to 17 in Canada had an autism diagnosis
88,175, children are registered in the Ontario Autism Program
WHO recommends accessible, community-based early interventions for children with autism — timely evidence-based psychosocial interventions improve communication and social engagement
23.4%, Only 20,666 children have active funding agreements () — less than one in four