Autism symptoms vary according to age at diagnosis

The US population study of more than 2500 eight-year-olds with autism showed that the children with poor non-verbal communication, imaginary play, repetitive motor behaviours and inflexible routines were more likely to be diagnosed at a younger age.

Conversely, those children with deficits in conversational ability, idiosyncratic speech and relating to peers were more likely to be diagnosed at a later age.

The median age at diagnosis of autism spectrum disorder decreased from 8.2 years of age in children with seven behavioural features to 3.8 years in children