Autism spectrum disorder is diagnosed on the basis of persistent differences in social communication and interaction, combined with restricted or repetitive behaviours or interests. The range of presentation is wide — it is a spectrum in the genuine sense — but certain patterns of development in the first two to three years of life are associated with later diagnosis, and recognising them allows earlier access to assessment and support.
For parents who have noticed something that concerns them, understanding what the early signs of autism look like — and what the referral pathway is — is more useful than either dismissal or alarm.
Healthbooq supports parents in monitoring their child's developmental progress with age-appropriate milestone tracking and guidance on when professional assessment is indicated.
What Autism Spectrum Disorder Is
ASD is a neurodevelopmental condition characterised by two core domains of difference: social communication and interaction (difficulty with back-and-forth conversation, sharing of interests, non-verbal communication including eye contact, gesture, and facial expression; difficulty developing and maintaining relationships); and restricted, repetitive patterns of behaviour, interests, or activities (repetitive movements, insistence on sameness, highly specific interests, unusual sensory responses).
ASD is not caused by parenting style, vaccines, or early childcare. It is a neurodevelopmental difference with a strong genetic component. The prevalence in the UK is estimated at around one to two percent of the population.
The Earliest Signs: Joint Attention and Social Communication
The earliest observable signs of autism typically involve social communication, and specifically a cluster of behaviours around joint attention — the capacity to share attention with another person about something in the shared environment.
By twelve months, most neurotypically developing children are pointing to show things to others (protodeclarative pointing — "look at that!"), following a pointing gesture to look at what is being indicated, showing objects to people to share interest in them, and responding consistently to their own name. Absent or significantly reduced pointing, following a point, and name response by twelve months are among the earliest signs that warrant attention.
Pretend play — using objects symbolically (a banana as a phone, a block as a car) — typically begins around twelve to eighteen months. Absent or very limited pretend play by eighteen months is another early indicator.
Eye contact in autism is often described as reduced, but it is more nuanced than this: some children with autism use eye contact in some contexts, and its presence does not rule out autism. More relevant is the degree to which the child uses eye contact as part of social communication — to share attention, express emotion, or check in with a caregiver.
Language and Communication Signs
Many children who are later diagnosed with autism have early language development that is apparently typical, followed by a plateau or regression — words appearing and then disappearing, or very limited word use relative to age. By eighteen months most children should have at least six to ten words; by twenty-four months, at least fifty words and some two-word combinations. An absence of these, in a child who does not have a hearing problem, warrants assessment.
Some children with autism have strong rote language — repeating phrases or sentences heard on television or from others (echolalia) — without yet using language flexibly for genuine communication. Echolalia is not itself a sign of autism but is a pattern worth noting alongside other features.
Repetitive Behaviours and Sensory Differences
Repetitive movements — hand-flapping, spinning, rocking — are often cited as early signs. Many young children engage in repetitive movements without having autism, so these should be considered in the context of other features rather than in isolation. More specific concerns include intense distress at environmental changes that would not bother most children, a very narrow range of accepted foods with strong texture or category preferences, or significant sensory sensitivity (covering ears at moderate noise levels, strong aversion to touch).
How to Raise Concerns
Concerns about autism should be raised with a health visitor or GP, who can refer for a developmental assessment. The MCHAT-R (Modified Checklist for Autism in Toddlers) is a validated screening tool used by professionals. Early identification and access to support — speech and language therapy, developmental support, occupational therapy where relevant — makes a meaningful difference to outcomes.
Key Takeaways
Autism spectrum disorder (ASD) is characterised by differences in social communication and interaction, alongside restricted or repetitive patterns of behaviour or interests. The earliest signs are typically observable in the second year of life and relate to social communication — joint attention, pointing, eye contact, response to name, and pretend play. Early identification leads to earlier access to support, which has meaningful benefits for developmental outcomes. Concerns should be raised with a GP or health visitor for referral; waiting to 'see how things develop' delays access to assessment and support.
