At what Age Is Autism Diagnosed? Early Signs and Expert Guidelines : Dr Nadeem Ghayas

November 7, 2025

Autism can often be noticed and diagnosed around 18 months to 3 years of age. Some children show signs earlier, but doctors usually make a clear diagnosis after the age of two. This is because, by that time, a child’s speech, behavior, and social skills become easier to observe.

In many cases, doctors and parents start to see signs before a child turns 2 — like not responding to their name, avoiding eye contact, or not showing interest in playing with others. However, every child grows differently, so doctors prefer to watch a child’s behavior over time before confirming autism.

For children who have milder symptoms, autism might not be noticed until they start school, when teachers or parents see that the child struggles with social skills, communication, or following routines.

Experts such as the American Academy of Pediatrics (AAP) and the Centers for Disease Control and Prevention (CDC) recommend that all children be screened for autism at 18 months and again at 24 months during regular doctor visits. This helps in finding autism early so that special help (called early intervention) can begin, which improves the child’s development.

References:

American Academy of Pediatrics (AAP), “Identification, Evaluation, and Management of Children with Autism Spectrum Disorder,” Pediatrics Journal, 2020.

Centers for Disease Control and Prevention (CDC), “Screening and Diagnosis of Autism Spectrum Disorder,” 2024.

National Institute of Mental Health (NIMH), “Autism Spectrum Disorder,”  2023