Autism spectrum disorder (ASD) is a neurodevelopmental disorder defined by persistent deficits in social communication and social interaction, accompanied by restricted, repetitive patterns of behavior, interests, or activities.

The signs of ASD are usually evident in early childhood. Though it is still considered a lifelong diagnosis, with appropriate early intervention, individuals with ASD can lead productive, inclusive, and fulfilling lives. Many children with ASD do well in school, participate in activities they enjoy, go on to college, and are employed in adulthood. For most parents and professionals, ASD can be a very puzzling and complex disorder. Though a great deal of its mystery has yet to be uncovered, we know much more about it than we did 10 years ago. Just as our understanding has evolved over the years, so has the way we define, diagnose, and treat ASD.