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Early Detection Guide
Recognize the early signs of autism in children aged 12-36 months. Evidence-based developmental milestones, red flags by age, and guidance for Ontario parents on when and how to seek assessment.
In brief
General information only, not a diagnosis, treatment plan, crisis service, or individual estimate. Confirm your next step with the linked source or a qualified professional.
Clinical research (American Academy of Pediatrics; Hyman et al., Pediatrics 2020) identifies the period from birth to age 6 as the brain’s peak neuroplasticity window. The World Health Organization separately states that timely access to early evidence-based psychosocial interventions can improve autistic children’s ability to communicate and interact socially.
Every month of delayed therapy during this developmental window can have lifelong impacts. Recognizing early signs and seeking assessment promptly gives your child the best chance for optimal development.
90% of brain development occurs before age 6. Early intervention capitalizes on this rapid growth period.
Ontario public autism assessments commonly take one to two years (varies by region). Private assessments can start this process in 2-4 months.
Children who receive early intervention show greater gains in language, social skills, and adaptive behavior.
These are warning signs that warrant professional assessment. Having one or more signs does not mean your child has autism, but it does mean you should discuss concerns with your pediatrician.
Regression refers to loss of previously acquired skills. About 20-30% of autistic children show regression, typically between 15-24 months.
If your child was using words and stopped, was socially engaged and withdrew, or lost other skills, contact your pediatrician immediately. Regression always warrants prompt assessment.
Track your child’s development across these key domains. The Concern column indicates when you should discuss with your pediatrician.
| Age | Expected Skill | Concern If... |
|---|---|---|
| 6-9 mo | Smiles responsively to familiar faces | No social smile |
| 9-12 mo | Uses gestures like reaching or waving | No gestures |
| 12-15 mo | Points to show interest, shares enjoyment | No pointing or sharing |
| 18-24 mo | Engages in simple pretend play | No pretend play |
| 24-36 mo | Plays cooperatively with other children | Plays alone only |
| Age | Expected Skill | Concern If... |
|---|---|---|
| 6-9 mo | Babbles with different sounds (ba, da, ma) | Quiet, no babbling |
| 12 mo | Says 1-2 words with meaning | No words |
| 18 mo | Says 10+ words, starts two-word phrases | Fewer than 10 words |
| 24 mo | Uses 50+ words, two-word phrases | No two-word phrases |
| 36 mo | Speaks in sentences, asks questions | Only echoes words |
| Age | Expected Skill | Concern If... |
|---|---|---|
| 9-12 mo | Looks at objects when you point | No joint attention |
| 12-18 mo | Imitates actions (waving, clapping) | No imitation |
| 18-24 mo | Follows simple one-step instructions | Does not understand |
| 24-36 mo | Sorts shapes, completes simple puzzles | No interest in toys |
| 24-36 mo | Shows interest in other children | Ignores other children |
The M-CHAT is a standard 20-question screening tool used at 18 and 24 months during well-child visits. It asks about social communication, joint attention, and repetitive behaviors.
Note: About 5% of children screen positive on M-CHAT. Of those, about 50% receive an autism diagnosis. The other half may have other developmental concerns or no diagnosis at all. A positive screen means further assessment is warranted.
Follow these steps if you are concerned about your child’s development. You are your child’s best advocate — if something feels wrong, pursue answers.
Write down specific behaviors, when you first noticed them, and how often they occur. Include videos if possible. This documentation is valuable for assessments.
Schedule an appointment with your child's doctor. Be specific about your concerns. Request a referral for autism assessment. In Ontario, you can self-refer to some regional centres.
The Modified Checklist for Autism in Toddlers (M-CHAT) is a standard screening tool. Your doctor may use it, or you can complete it online. Positive screening does not mean autism - it means further assessment is needed.
Ask about: (1) a public hospital-based autism assessment clinic, or (2) a regional Children's Treatment Centre. Intake, referral requirements, and capacity vary, so ask the current team what happens next.
If a private route is an option for your family, ask providers for current intake, credentials, assessment scope, report requirements, and a complete written quote. Earlier assessment does not guarantee a particular service or outcome.
Once you receive an autism diagnosis, call Access OAP at 1-833-425-2445 immediately to register.
Your child’s position on the OAP waitlist is based on the registration date, not the diagnosis date. Every day matters.
Central intake for Ontario Autism Program. Call to register after diagnosis.
Provides public autism assessments, early intervention services, and family support.
Parent support, information, and advocacy across all Ontario regions.
Find qualified psychologists for private autism assessment in your area.
Community services directory for autism resources and support in your area.
Use our printable milestone tracker to document your child’s development and prepare productive conversations with your pediatrician. Early tracking supports early intervention.
Print this checklist to track your child’s development. Bring to pediatrician appointments to discuss concerns.
Parents know their children best. If you are concerned about development, do not wait. Early assessment leads to earlier intervention, and early intervention leads to better outcomes.
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Learn more about supporting your child's development while you wait.
When should parents seek autism assessment?
VerifiedClinical guidelines recommend autism screening at 18 and 24 months during routine check-ups, with referral for full assessment if red flags appear. [AAP] In Ontario, early identification matters critically because every month of diagnostic delay pushes children further from the early intervention window (ages 0-4) that research shows maximizes outcomes.
Source: American Academy of Pediatrics [AAP] · Open source record
Can autistic students get an educational assistant (EA)?
VerifiedSchools may assign EAs based on IEP needs, but 47% of families report insufficient supports. EA availability varies by board and often fails to match clinical needs, leaving many autistic students without necessary classroom support.
Source: Ontario Education Act & OAC · Open source record
What is IPRC and why does it matter?
VerifiedThe Identification, Placement and Review Committee (IPRC) is a formal school board process that officially identifies students as "exceptional" under Ontario education law. [Education Act] Requesting an IPRC can provide additional resources and protections, though many parents are unaware this formal identification process exists or that they can request it.
Source: Ontario Education Act · Open source record
Sources on this page
Key claims are paired with their source, evidence tier, and verification date so readers can inspect the public record directly.
Evidence supports autism screening and intervention commencing in the first 2 years of life — earlier identification directly enables earlier intervention during the highest neural plasticity window
1 in 50
According to the 2019 Canadian Health Survey on Children and Youth, about 1 in 50 children and youth aged 1 to 17 in Canada had an autism diagnosis
WHO recommends accessible, community-based early interventions for children with autism. Timely evidence-based psychosocial interventions improve communication and social engagement
See authorship, freshness, trust signals, and ways to stay current.
Founder & Autism Advocate