Pervasive developmental disorders (PDD) — now known as autism spectrum disorder (ASD) — refers to a group of conditions that affect average development. It may appear as a delay in development of ...

Autism spectrum disorder, or ASD, is the clinical name for the condition most people refer to as autism. Autism is defined as "a complex developmental condition that affects communication, social ...

People with autism spectrum disorder may meet similar diagnostic criteria, but the way their symptoms present in daily life can be very different. If you’re concerned about your autistic teen’s ...