Early detection of ASD is the single most important prognostic factor. Intervention in the first two years of life, when neuroplasticity is at its peak, can significantly modify the developmental trajectory. No single sign is diagnostic of ASD, but a pattern of signs always justifies professional consultation.
ASD / Autism
Early signs of ASD: when and how to detect autism
Warning signs in babies: 0-12 months
The earliest warning signs relate to early social development: reduced or absent social smile (2-3 months), limited eye contact, scarce joint attention, reduced response to own name (9-10 months) and little imitation. Loss of previously acquired skills (regression) is always a red flag requiring immediate referral, regardless of age.
Warning signs at 12-24 months: the key period
| Expected milestone | Typical age | Warning sign |
|---|---|---|
| Pointing to request | 12 months | Does not point |
| Pointing to share | 12-14 months | Does not share attention |
| First meaningful words | 12-18 months | Absence of communicative words |
| Two-word phrases | 24 months | Absent or very limited |
Signs at 2-5 years: when the social context expands
With the start of nursery school (2-3 years), educators and families often detect the first significant differences: preference for solitary play, ritualistic behaviours and resistance to change, intense and restricted interests, stereotyped motor behaviours (hand-flapping, rocking), sensory hypersensitivity and difficulty understanding others' emotions.
What to do if you notice warning signs?
The first step is to consult your GP or paediatrician. If there are indicators, they will refer to specialised services: early intervention services, child neurology or psychiatry for formal diagnosis, and child neuropsychology for functional profile assessment. A tool like NeuroClarify can help organise observations and prepare the first specialist consultation.
Frequently asked questions
Language delay at 18 months can have many causes. The presence or absence of other signs (eye contact, joint attention, imitation) helps determine whether ASD risk is elevated. The first step is a paediatrician visit with full developmental assessment.
ASD can be reliably diagnosed from 18-24 months by experienced specialists. In high-functioning ASD (Level 1), the diagnosis may not be established until age 5-8 or even adolescence.
Want personalised guidance?
Take our free assessment and get a personalised neuropsychological profile in about 15 minutes.
Start free assessment