According to DSM-5 criteria, autism spectrum disorder is characterized by persistent deficits in social communication and interaction, along with restricted, repetitive patterns of behavior, interests, or activities. At what age must symptoms be present for an ASD diagnosis to be made?

## DSM-5 Diagnostic Criteria for Autism Spectrum Disorder ### Onset Requirement **Key Point:** According to DSM-5, symptoms must be present in the *early developmental period*, but they do not need to be fully manifest from birth. Symptoms often become apparent when social demands exceed the child's limited capacities. **High-Yield:** The DSM-5 criterion specifies "symptoms must be present in the early developmental period (but may not fully manifest until social demands exceed limited capacities)." This is a critical distinction from earlier DSM-IV criteria. ### Clinical Pearl Many children with ASD, particularly those with average or above-average intelligence (previously called Asperger syndrome), may not show obvious symptoms until they enter school or social settings where peer interaction becomes more complex and demanding. Parents often report that symptoms became noticeable around age 2–3 years when language delay or social withdrawal became apparent. ### Timing Clarification - **Early developmental period** = typically first 2–3 years of life - Symptoms may be masked by high intelligence or supportive environments - Diagnosis can be made at any age once criteria are met, but onset must be in early development **Mnemonic:** **EDP-ASD** — Early Developmental Period for Autism Spectrum Disorder onset.