Autism is a wide spectrum, and one autistic child looks very different from another. But certain patterns in the first two to three years tend to come up in children who are later diagnosed, and recognising them early matters. The "wait and see" approach that used to be standard delays support during the most plastic stretch of brain development — and in the UK it now means joining a multi-year NHS waiting list later rather than sooner.
If you've noticed something — about how your child communicates, plays, or responds to you — this article will tell you what's worth raising and how to raise it. Mild concern is a perfectly good reason to talk to your health visitor or GP.
Healthbooq helps parents track their child's development with milestone guidance and clear pointers on when professional assessment is appropriate.
What autism is
Autism is a neurodevelopmental condition, not an illness or a behaviour problem. The diagnostic criteria (DSM-5 and ICD-11) require differences in two areas: social communication and interaction, and restricted or repetitive patterns of behaviour, interests, or activities.
Autism is strongly genetic — twin studies put heritability around 60–90%. It is not caused by vaccines (large studies repeatedly confirm no link, e.g. Hviid et al. 2019 in Annals of Internal Medicine, with a sample of 657,000 children), parenting style, or childcare arrangements. UK prevalence is roughly 1–2% of the population.
The earliest signs: joint attention and shared social communication
The cluster of behaviours that most reliably predicts later diagnosis falls under "joint attention" — the ability to share attention with another person about something in the environment. Most neurotypically developing children, by around 12 months, are doing the following:
- Pointing to share interest — protodeclarative pointing, "look at that!" — not just to request something.
- Following someone else's point — turning to look at what an adult is pointing at.
- Showing objects — bringing you a toy to show, not just to give.
- Responding consistently to their name. Not always (toddlers ignore their parents) — but turning to look at least most of the time.
- Waving and using a few simple gestures.
Reduced or absent versions of these by 12–14 months are among the strongest early markers. Pointing in particular has been called one of the single most reliable early signs — autistic children, on average, point less and later than neurotypical peers.
Pretend play typically starts around 12–18 months — feeding a teddy, using a banana as a phone, putting a doll in a pram. Absent or very limited pretend play by 18–24 months is another consistent indicator.
Eye contact is more nuanced than the stereotype. Some autistic children make plenty of eye contact in some contexts. What's more telling is whether eye contact is used to share something — to check in with you, to share a moment of delight, to coordinate attention — or whether it's missing in those moments.
Language patterns
Some autistic children have early language that looks typical and then plateaus or regresses — words appearing and then disappearing, or no new words for months. Rough benchmarks:
- By 18 months: at least 6–10 words
- By 24 months: at least 50 words and starting two-word combinations ("more milk," "Daddy gone")
- By 30 months: 200+ words and short sentences
A child below those thresholds — assuming hearing has been checked, which it should be — warrants assessment. Speech delay is not always autism (it can be a language disorder, hearing impairment, or simple late talking), but it's a reason to see your health visitor.
Echolalia — repeating phrases from TV or others, sometimes weeks after hearing them — is common in autism, but on its own it isn't diagnostic. Toddlers repeat what they hear. What matters is whether the child also has flexible, communicative language, or whether scripted repetition is most of what they produce.
Repetitive behaviours and sensory differences
Hand-flapping, spinning, rocking, tiptoeing — many neurotypical toddlers do all of these sometimes, especially when excited. They become a flag when they are frequent, prolonged, and combined with other features.
More specific patterns worth noting:
- Intense distress at small environmental changes that wouldn't bother most peers — a different route to nursery, a rearranged living room, the wrong cup.
- Very narrow food acceptance with strong texture or category preferences — only beige food, only one specific brand of chicken nuggets, gagging at unfamiliar textures (more than typical "fussy eating").
- Obvious sensory sensitivity — covering ears at moderate sounds (vacuum, hand dryer), strong aversion to certain clothing textures (socks with seams, labels), or the opposite — seeking intense sensory input, crashing into things, very high pain tolerance.
- Lining up objects in long sequences, repeatedly, or playing with parts of toys (spinning the wheels of a car for ten minutes) rather than the toy as a whole.
Regression
Loss of previously acquired language or social skills, usually between 15 and 24 months, is reported in around 20–30% of autistic children. Words that were used regularly disappear, or a child stops responding to their name when they used to. Regression at this age is uncommon enough in non-autistic children that it should always prompt prompt referral — within weeks, not months.
What to do if you're concerned
Talk to your health visitor or GP. The MCHAT-R/F (Modified Checklist for Autism in Toddlers, Revised with Follow-up) is a validated screening tool used by professionals; it's free online and you can complete it yourself for an initial sense of whether your concerns warrant referral, but it's a screen, not a diagnosis.
If you raise concerns and are told "let's wait and see" but you're still worried after a few months, escalate. NICE guidance (NG142) says referral should not be refused on grounds of age, verbal ability, or because the child doesn't show concerning features in every setting. You can ask for the reasoning to be put in your child's notes.
NHS autism assessment waits in the UK now often run over a year. While you wait, you can usually access:
- Speech and language therapy referral (often a separate, shorter wait)
- Health visitor developmental support
- Local authority early-help services (Portage in some areas — home-based developmental support for under-5s)
- Local Tier 2 SEND support through nursery if your child is in childcare
Don't wait for the diagnosis to start the support. Early intervention works because of the developmental window, not because of the paperwork.
Key Takeaways
The earliest signs of autism are usually visible in the second year of life and cluster around social communication: pointing to share interest, following someone's pointing finger, responding to their own name, showing objects to others, and pretend play. Reduced or absent versions of these by 12–18 months are the most reliable early markers. Loss of previously acquired language or social skills (regression, usually 15–24 months) happens in roughly 20–30% of autistic children and warrants prompt referral. Don't wait and see — earlier referral means earlier access to speech and language therapy, occupational therapy, and developmental support.
