At what age can autism spectrum disorder be reliably diagnosed?

Classic autism can be reliably diagnosed after 16 months of age. However, advancements in screening methods have enabled the detection of the condition as early as 12 months of age.12

Diagnosis is conducted through a combination of medical history, behavioral observations, and screening for developmental delays. During regular medical checkups, clinicians screen for the absence of specific behaviors, such as eye contact, pointing, and pretend play, often utilizing parent-completed questionnaires. If a child is identified as being at risk for autism spectrum disorder, they undergo a comprehensive medical evaluation, which may include assessments of hearing and vision, genetic testing, and neurological and psychological examinations.12