Early signs of autism or ADHD in toddlers
You have probably been up late reading checklists, finding your child in some of them and not others, and feeling no clearer. This page will not tell you whether your child is autistic. It will tell you what is genuinely worth noticing, what is just being two, and what to do next.
In short
- Patterns matter, single behaviours don’t. Nearly every “sign’ on its own is also just normal toddler behaviour.
- Autism can often be recognised from around 18 months to 2 years, though many children are identified much later.
- ADHD is rarely diagnosed under 5. At three, inattention and impulsiveness are the job description.
- You do not need a diagnosis to get support. Support and diagnosis are two separate queues — join both.
- Waiting lists are long. Referring early costs you nothing if you turn out to be wrong.
- Trust the pattern you can describe, not the checklist you can tick.
This is information, not a diagnosis — and it cannot be one.
Autism and ADHD are diagnosed by specialist multidisciplinary teams over multiple appointments, using structured assessments and information from several settings. No article, checklist or online quiz can do that, and anything claiming otherwise should be closed. Use this to decide whether to ask for an assessment — nothing more.
Why checklists mislead
Take almost any item from an autism checklist. Lines up toys. Doesn’t always answer to their name. Hates the seam in their socks. Watches the same film forty times.
Every one of those describes an enormous number of children who are not autistic. Which is why reading a list and counting your hits tells you very little, and why you can come away from an evening of searching feeling both convinced and unconvinced.
What clinicians actually look at is different. They look for a pattern across several areas at once, present most of the time, in more than one place, and having a real effect on daily life.
A more useful question than “does he do X?”
Ask instead: “How does my child let me know they want something? How do they show me something they’re pleased about? What happens when the plan changes?” Those questions get at communication, shared attention and flexibility — which is what actually matters. Your answers will also be far more useful to a professional than a ticked list.
What early autism can look like
Grouped the way professionals tend to think about it. Person-first or identity-first language varies — many autistic adults prefer “autistic child” to “child with autism”, and it is worth asking families what they prefer.
Social communication and shared attention
- Rarely pointing at things simply to show you — pointing to request, but not to share.
- Not often following your point or your gaze to look at what you are looking at.
- Limited back-and-forth: fewer of the little exchanges of expression, sound and gesture that make up early conversation.
- Not consistently responding to their name by around 12–18 months, when hearing has been checked.
- Eye contact that is fleeting or used differently — though plenty of autistic children do make eye contact.
- Little pretend play by around 2–3 — not feeding the teddy, not making the brick be a phone.
Of everything on this page, shared attention is the one clinicians weight most heavily. A child who brings you a beetle to look at purely because they want you to see the beetle is doing something socially sophisticated.
Repetitive behaviour, routines and sensory differences
- Strong need for sameness, and distress at small changes — a different route, a different cup.
- Lining up, ordering or sorting objects, often intensely and for long stretches.
- Repetitive movement — hand flapping, toe walking, spinning, rocking — particularly when excited or overwhelmed.
- Very intense interests, narrower and more absorbing than usual for their age.
- Sensory differences in either direction: covering ears at hand dryers, hating labels or textures, or seeking out spinning, pressure and crashing.
- Eating a very restricted range of foods, often by texture or colour rather than taste.
The one to act on quickly
If your child had skills and lost them — used words and stopped, used to wave or point and no longer does — contact your GP or health visitor promptly rather than waiting. Regression is uncommon and always warrants a proper look.
What is just being a toddler
Worth saying plainly, because these send a lot of parents into a spiral at midnight.
Not, on their own, signs of anything
- Tantrums — even enormous ones. Two-year-olds have huge feelings and no brakes. That is the developmental stage, not a symptom.
- Ignoring you. Especially when absorbed, or when what you have said is unwelcome.
- Lining things up. Sorting and ordering is a normal way of exploring how the world works.
- Watching the same thing on repeat. Repetition is how small children learn.
- Fussy eating. Extremely common between 2 and 4.
- Toe walking. Common in under-3s and usually resolves. Worth mentioning if it persists or is the only way they walk.
- Being shy, intense, busy, or a late talker. All within ordinary variation.
The difference is rarely the behaviour itself. It is how much of it there is, how many areas it spans, how long it has gone on, and whether it is getting in your child’s way.
ADHD, and why nobody will diagnose it yet
ADHD is very seldom diagnosed before school age, and there are good reasons for that.
The diagnostic criteria require that difficulties are beyond what is normal for the child’s developmental stage, present in more than one setting, and causing real impairment. At three, being inattentive, impulsive and physically relentless is the normal developmental stage. There is no reliable way to separate an under-five with ADHD from an under-five who is simply three.
Most children are picked up once school makes new demands — sitting still, sustained attention, waiting a turn — which is why referrals cluster around ages 5 to 8.
That said, some things are worth recording now, so that you have a history if it becomes relevant:
- Activity levels far beyond other children the same age, consistently, in every setting.
- Impulsiveness that repeatedly leads to danger despite constant reminders — running into roads, climbing regardless of height.
- Sleeping much less than typical for their age, over a long period.
- Nursery or childminder raising it independently of you.
Two things at once
Autism and ADHD very often occur together, and their early signs overlap. If you are wondering about both, say so at the referral. Ask for a neurodevelopmental assessment rather than naming one condition — it keeps the door open.
Why it gets missed — especially in girls
Autistic girls are diagnosed later than boys, on average, and many not until adolescence or adulthood. The reasons are worth knowing.
- Masking. Some children work very hard to copy what other children do. It looks like coping. It is exhausting, and it hides the difficulty.
- The all-day meltdown gap. A child can hold it together at nursery and fall apart the moment they get home. Staff then report no concerns, and you are quietly disbelieved.
- Interests that look ordinary. An intense interest in horses or a particular book attracts less attention than an intense interest in washing machines — even when it functions identically.
- Sociability. Many autistic children very much want friends. Wanting friendship does not rule anything out; the difficulty is often in the mechanics of it.
If home and nursery see different children
That difference is data, not a contradiction — and it is one of the most commonly missed signals. Say it explicitly at any appointment: “She copes at nursery and melts down for two hours every day when she gets home.” Do not let it be smoothed over.
What to do next
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Write down what you actually see
For two weeks, jot down real examples with dates. Not “struggles with change” but “Tuesday: cried for 40 minutes because we drove a different way to nursery.” Specific examples are what move a referral along.
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Get hearing checked
Always. A child who cannot hear you reliably can look like a child who is not responding. Glue ear is common, treatable, and comes and goes.
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Talk to your health visitor or GP
Ask directly for a referral for a neurodevelopmental assessment. Take your notes. If you are told to wait and see and you are not satisfied, you can ask again — and you can ask for the reason to be recorded.
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Talk to your nursery or childminder
Ask what they see, and ask them to write it down. A setting’s observations carry real weight because they see your child alongside thirty others the same age. Ask about their SENCo and whether they can involve the council’s Area SENCo.
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Ask about speech and language too
If communication is part of your concern, a speech and language referral can often be made in parallel — and frequently moves faster. See our guide on a two-year-old who isn’t talking yet.
Getting support before any diagnosis
Assessment waits are frequently measured in years. The single most useful thing to understand is this: support does not require a diagnosis.
- Your setting’s duty starts now. Under the Equality Act 2010 they must make reasonable adjustments for a disabled child, diagnosis or not. Our reasonable adjustments letter puts that in writing.
- SEN support starts now. Settings should be running the assess–plan–do–review cycle without waiting for anyone.
- An EHC needs assessment does not require a diagnosis either. The test is need, not label. See getting an EHC needs assessment for an under-5.
- Check DLA. Disability Living Allowance can be claimed for a child needing substantially more care than others their age — again, no diagnosis required. It can also unlock funded childcare and the Disability Access Fund.
- Find your council’s Local Offer for what exists near you.
If your head is a mess about this
Most parents arrive here having felt several things at once: worry, guilt about the worry, guilt about wanting an answer, and a fear of being the parent who went looking for a label.
Worth saying plainly. Seeking an assessment does not create anything. It is not a self-fulfilling prophecy, and it is not giving up on your child. It is asking someone who knows what they are looking at to look.
Most parents come out of it either reassured, or holding something practical they can act on. And children who get the right support early — before school, while the world is still small and forgiving — generally do better than those who get it after years of everyone hoping.
You know something
Parents are often wrong about what is going on. They are much less often wrong that something is. If you have read this far, that is worth taking seriously — not as a diagnosis, but as a reason to make the phone call.