Korean Clinical Guideline for Autism Spectrum Disorder - Clinical Features, Course, Epidemiology, and Cause

Autism spectrum disorder (ASD) is a heterogeneous developmental disorder characterized by impairments in two core areas: 1) social communication and interaction and 2) restricted and repetitive patterns of behaviors and interests. In general, ASD is known to be a lifelong disorder. Follow-up studies from childhood to adulthood have reported that the severity of the key symptoms ASD decreases over time. However, chronic health problems including mental health occur in many patients with ASD. The prevalence of ASD has increased from around 0.04% in the 1970s to 2.8% at present. The average age of diagnosis in developed countries is 38-120 months of age. Recent evidence suggests that biological factors which include genetic, congenital, immunological, neuroanatomical, biochemical, and environmental ones are important in causing autism. Until now, early signs and various risk factors of ASD have been suggested.