A group of developmental disabilities relating to how the brain processes information. Three main types are:

• Autistic disorder (classic autism): Includes significant language delays, social and communication challenges, unusual behaviors and interests.

• Asperger syndrome: Usually milder symptoms. May have social challenges, unusual behaviors or interests, but not language or intellectual disability.

• Pervasive developmental disorder—not otherwise specified (atypical autism): Usually have fewer and milder symptoms that might cause only social and communication challenges.

Source: U.S. Centers for Disease Control and Prevention