What is the average age of autism diagnosis?

• A. 18 months
• B. 24 months
• C. 48 months (4 years)
• D. 60 months

Answer: (C)

The key idea is that while autism signs often emerge in the first two years, the typical age at which a formal diagnosis is made in clinical practice is around four years old. Universal screening tools can flag concerns as early as 18–24 months, but a definitive diagnosis generally requires comprehensive assessment over time and observation across multiple contexts, using standardized criteria. This means many children are diagnosed around preschool age, when their social communication deficits and repetitive behaviors are clearer and can be evaluated with reliable tools. So, 48 months (4 years) best reflects the common age at diagnosis. The earlier ages reflect screening windows, not the point at which diagnosis is usually confirmed, and 60 months is later than average.