Essentials of Autism Spectrum Disorders - Hardcoverby Draco Oldman (Editor) Autism spectrum disorder (ASD) refers to a type of disorder that appears in early childhood and is distinguished by qualitative abnormalities in social interactions. The disorder can also be characterized by impaired communication skills and restricted repetitive behaviors, activities and interests. As autism is a spectrum disorder, each autistic individual has a unique set of abilities and difficulties. The manner in which