Getting your child assessed for autism is, for most families, a long and bumpy process. It usually starts with you noticing something — a lack of pointing at 14 months, a regression in words at 18, a pattern of meltdowns at the school gate at 3 — and it ends, eventually, with a multi-disciplinary team telling you whether the diagnostic criteria are met.
Knowing what the process actually involves takes some of the fog out of it. This article walks through the early signs that typically prompt referral, how the NHS pathway works in England, what an ADOS-2 looks like in practice, and what happens after a diagnosis.
Healthbooq helps parents understand developmental concerns in early childhood, including the signs, the referral pathway, and what an autism assessment involves.
What autism is
Autism spectrum disorder (ASD, or just autism — many autistic people prefer the simpler term) is a neurodevelopmental condition. The diagnostic criteria in DSM-5 and ICD-11 require differences in two domains: social communication and interaction, plus restricted or repetitive patterns of behaviour, interests, or activities. The presentation varies enormously — one autistic child may be non-speaking with significant support needs, another may be a chatty 4-year-old who scripts dialogue from their favourite show and falls apart at supermarket lights.
Autism is strongly genetic. Heritability estimates from twin studies sit around 60–90%. Environmental factors that have been ruled out by repeated, large-scale studies include: vaccines (definitively, repeatedly — see Hviid et al. 2019, Annals of Internal Medicine, n=657,000), parenting style, and diet. Differences in brain development are present from very early in life, though they may not be observable until the social demands on the child outpace their capacity.
Early signs that prompt referral
The signs that lead to assessment in the first few years are mostly social-communication ones. By 12–18 months, most neurotypical children are:
- Pointing to share interest ("look at that!" — protodeclarative pointing), not just to request
- Following someone else's pointing finger and looking where it directs
- Responding consistently to their own name
- Showing objects to people to share enjoyment
- Waving and using a few gestures
- Using around 6–10 words by 18 months, around 50 by 24 months with some two-word combinations
Reduced or absent versions of these patterns are the most reliable early markers. The 18-month Healthy Child Programme review in the UK is specifically looking for them.
The other cluster is restricted or repetitive behaviour: deep distress at small routine changes, intense narrow interests, repetitive movements (hand-flapping, rocking, lining objects up), and unusual sensory responses (covering ears at moderate noise, refusing whole categories of food by texture).
Regression — the loss of previously acquired language or social skills, usually between 15 and 24 months — is a flag that warrants prompt referral. It happens in roughly 20–30% of autistic children and is uncommon enough in non-autistic development to take seriously.
The referral pathway in England
Referral can be initiated by a GP, health visitor, paediatrician, nursery, or school SENCO. Parents can ask any of these to make the referral — you don't need to wait for a professional to suggest it.
NICE guidance (NG142, 2017) is explicit that referral should not be refused on grounds of age, verbal ability, or because the child does not show concerning features in every setting. If you've been told "let's wait and see" and you're still worried after a few months, escalate. Health visitors can refer directly in most areas; if your GP is reluctant, ask for a written reason in your child's notes.
NHS waits for assessment have lengthened sharply in the last few years. National data from 2023 showed average waits of well over a year in many areas; some are over two. This is a real and painful gap. Private assessment through a recognised provider (multi-disciplinary, ADOS-2-based) typically costs £1,500–£3,000 and produces a diagnosis that the NHS and most schools accept. Some families pursue both routes simultaneously: NHS for the long-term care pathway, private for an earlier diagnosis.
What the assessment actually involves
A good early-childhood autism assessment is multi-disciplinary. Typically that means a developmental paediatrician or child psychiatrist, a speech and language therapist, and a clinical or educational psychologist. They combine information from several sources:
- Detailed developmental history with parents — pregnancy, birth, early milestones, current concerns, family history. Often using a structured interview like the ADI-R (Autism Diagnostic Interview-Revised) for older children, or a less formal version with toddlers.
- Direct observation of the child — usually using the ADOS-2 (Autism Diagnostic Observation Schedule, second edition). This is a structured 45-minute play session with specific activities designed to draw out social communication and repetitive behaviours. Modules are matched to age and language level — Toddler Module for 12–30 months without speech, Module 1 for verbal age <30 months, Module 2 for fluent phrases, Module 3 for fluent speech, Module 4 for adolescents/adults.
- Reports from nursery or preschool — often via questionnaire (SCQ, SDQ) plus narrative observations.
- Cognitive, language, and adaptive functioning assessment — to understand the broader profile and identify co-occurring conditions.
Diagnosis is made using DSM-5 or ICD-11 criteria. The ADOS-2 alone is not the diagnosis; it's one piece of evidence the team weighs alongside developmental history and clinical judgement. A child who scores below the cut-off on the ADOS-2 can still be diagnosed if the broader picture supports it (this happens fairly often with autistic girls who mask in unfamiliar settings).
Reliable diagnosis is possible from around 18–24 months in clear cases, though many children are diagnosed later.
After the diagnosis
A diagnosis opens doors that were closed before:
- Therapy services — speech and language therapy, occupational therapy (often for sensory needs), early-intervention programmes.
- Educational support — SEND support in mainstream school, with an EHC (Education, Health and Care) plan if needs are more significant. EHC assessment is a parental right to request; the local authority must respond within 6 weeks.
- Benefits — Disability Living Allowance for children under 16; the rate depends on care and mobility needs. Carer's Allowance for parents who provide 35+ hours/week of care, with eligibility rules around income.
- Specialist placements if mainstream isn't right.
It also gives you a frame. Many parents describe a complicated mix of grief, relief, and clarity after the appointment. The grief is often about the version of childhood you'd been picturing; the relief is about finally having a name for what you've been seeing; the clarity is about now knowing what to do.
The National Autistic Society (autism.org.uk) is the main UK resource — guidance for families, school advocacy support, and a helpline. Local autism parent support groups, often run via local authorities or charities, are worth seeking out early.
Key Takeaways
Autism diagnosis in early childhood is done by a multi-disciplinary team — usually a developmental paediatrician or psychiatrist, a speech and language therapist, and a clinical or educational psychologist. They combine standardised observational tools (most often the ADOS-2) with detailed developmental history and reports from nursery or preschool. NHS waits in the UK currently average over a year in many areas; private assessment is faster but typically costs £1,500–£3,000. Earlier diagnosis means earlier access to speech and language therapy, occupational therapy, and educational support — and better outcomes on average. Reliable diagnosis is possible from around 18–24 months.
