A 3-year-old boy is brought for evaluation because his parents are concerned about his development. He does not respond to his name being called, avoids eye contact, has not developed any words, prefers lining up toys over imaginative play, and becomes intensely distressed if his daily routine changes. He was a quiet infant who did not babble. Hearing is normal on audiology testing. What is the most likely diagnosis?

• A Intellectual disability
• B Childhood schizophrenia
• C Autism spectrum disorder ✓
• D Selective mutism

Explanation

Autism spectrum disorder (ASD) is characterized by persistent deficits in social communication and interaction (absent joint attention, failure to respond to name, limited eye contact, language delay) AND restricted, repetitive patterns of behavior (insistence on sameness, stereotyped play, rigid routines). Symptoms must be present in early development, though they may not fully manifest until social demands exceed capacity. ASD encompasses former diagnoses of autistic disorder, Asperger's, and PDD-NOS. Childhood schizophrenia is rare below age 13. Intellectual disability may co-occur but does not explain the social-communication profile.

Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.

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Written and medically reviewed by the StethoPrep medical team.