You want the numbers, and you want to know which ones to trust. This page keeps only figures we could open at the source during our review, or that survived our March 2026 fact-check. Every number carries its source and year. If a number you have seen elsewhere is missing, it is because we could not verify it, not because we forgot it.
How to read prevalence numbers
Nearly every autism statistic is diagnosed prevalence: how many children the system has identified, not how many are autistic. Recorded rates reflect the people identified by the studies’ methods. A change in a recorded rate does not, by itself, establish its cause. 1, 3
Canada
| Figure | Value | Source, year |
|---|---|---|
| Children and youth aged 1 to 17 with an autism diagnosis | 1 in 50 (2.0%) | Canadian Health Survey on Children and Youth (CHSCY), 2019, published by the Public Health Agency of Canada |
| Same measure, later cycle | 3.0% | CHSCY 2023, reported on Health Infobase Canada |
| By sex, 2019 | Males 1 in 32 (3.1%); females 1 in 125 (0.8%) | CHSCY 2019 |
| By sex, 2023 | Males 4.3%; females 1.5% | CHSCY 2023, Health Infobase |
| By age group, 2019 | Ages 1 to 4: 1.1%; ages 5 to 11: 2.5%; ages 12 to 17: 1.9% | CHSCY 2019 |
| Median age at diagnosis | 3.7 years | CHSCY 2019 |
| Diagnosed before age 5 | 53.7% of diagnosed children | CHSCY 2019 |
| Autistic children with at least one other long-term condition | 68.7% | CHSCY 2019 |
| Autistic children also diagnosed with ADHD | 36.5% | CHSCY 2019 |
| Autistic children aged 5 to 17 with a learning disability | 48.1% | CHSCY 2019 |
| Autistic children aged 5 to 17 with an anxiety disorder | 22.5% | CHSCY 2019 |
The low figure for ages 1 to 4 is not because fewer toddlers are autistic. It is because many have not been diagnosed yet. That gap is the subject of the early signs and waiting pages. 1
Quebec
| Figure | Value | Source, year |
|---|---|---|
| Crude prevalence, ages 1 to 17 | 1.7% (confidence interval 1.2 to 2.2) | CHSCY 2019, provincial table |
| Prevalence, ages 1 to 17, administrative data | About 1.2% of ages 1 to 17 in 2014-15, after a steady rise over the decade | Diallo et al., Canadian Journal of Psychiatry, 2018 |
| Annual incidence, under 18 | 19 per 10,000 in 2014-15 | Diallo et al., 2018 |
| Boys versus girls, incidence | About 4 times higher in boys | Diallo et al., 2018 |
| Regional variation | About 3-fold across regions, Montreal metropolitan area highest | Diallo et al., 2018 |
The Quebec study used health-insurance and hospital records. Differences in recorded rates do not, by themselves, establish why regions differ. 3
The sex ratio, corrected
The old rule of thumb is four boys for every girl. A 2017 meta-analysis found that pooling all studies gives about 4.2 to 1, but the higher-quality studies, which screened whole populations rather than counting clinic referrals, gave about 3.3 to 1. The authors concluded the true ratio is closer to 3 to 1 and that girls are being missed. 4 The 2019 Canadian survey ratio of 3.9 to 1 is a diagnosed ratio and fits that picture. See girls, quiet kids and masking.
ADHD in Canada
A 2022 review of Canadian studies found one estimate across five provinces of 8.6% diagnosed ADHD among children and youth, and 2.9% among adults, with wide variation by age, sex, province and year. 5 We do not show a Quebec-specific ADHD figure because the one in circulation could not be traced to a page we could open. Overlap between autism and ADHD is common; the 36.5% figure above is the Canadian survey's own.
The wider world, for context only
The World Health Organization's fact sheet estimates that in 2021 about 1 in 127 people worldwide were autistic. 6 International numbers vary widely with how, and whether, children are assessed; they are not a benchmark for Quebec.
Wait times and cost in Montreal
These are not statistics in the epidemiological sense, but parents search for them alongside the numbers above. Autisme Montréal reports that public hospital waiting lists for an autism evaluation range between 6 and 24 months, and that private evaluations cost between $1,600 and $4,200. 7 These are dynamic; the assessment page explains the trade-off, and you should confirm current figures on Autisme Montréal's page before deciding.
What we removed
Our March 2026 fact-check found several widely shared figures were wrong or misattributed: a "2 times more boys" ADHD claim that was actually 1.8 to 1, a CDC data brief cited for adults that was about children, and a percentage attributed to a journal article that was not in the article. Details are on the methodology and corrections page. The lesson we drew is on every page of this site: fewer numbers, each with a door you can open.
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Sources
- Autism spectrum disorder: highlights from the 2019 Canadian Health Survey on Children and Youth (2022) ↩1 ↩2
- Prevalence: chronic conditions in childhood (2019)
- Prevalence and correlates of autism spectrum disorders in Quebec (2018) ↩1 ↩2
- What is the male-to-female ratio in autism spectrum disorder? A systematic review and meta-analysis (2017) ↩1
- A review of Canadian diagnosed ADHD prevalence and incidence estimates published in the past decade (2022) ↩1
- Autism fact sheet (2025) ↩1
- How to get a diagnosis (2026) ↩1