What Are the Types of Autism Spectrum Disorders?

Autism spectrum disorders include social, communication, and behavioral challenges. These problems can be mild, severe, or somewhere in between.

Early diagnosis is important, because early treatment can make a big difference.

What Conditions Are Considered Spectrum Disorders?

Until recently, experts talked about different types of autism, such as autistic disorder, Asperger’s syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS). But now they are all called “autism spectrum disorders.”

If you still hear people use some of the older terms, you’ll want to know what they mean:

Asperger's syndrome. This is on the milder end of the autism spectrum. A person with Asperger's may be very intelligent and able to handle her daily life. She may be really focused on topics that interest her and discuss them nonstop. But she has a much harder time socially.

Pervasive developmental disorder, not otherwise specified (PDD-NOS). This mouthful of a diagnosis included most children whose autism was more severe than Asperger's syndrome, but not as severe as autistic disorder.

Autistic disorder. This older term is further along the autism spectrum than Asperger’s and PDD-NOS. It includes the same types of symptoms, but at a more intense level.

Childhood disintegrative disorder. This was the rarest and most severe part of the spectrum. It described children who develop normally and then quickly lose many social, language, and mental skills, usually between ages 2 and 4. Often, these children also developed a seizure disorder.

Is Rett Syndrome an ASD?

Children with Rett syndrome often have behaviors similar to autism, and experts used to group it among spectrum disorders. But now that it’s known to be caused by a genetic mutation, it’s no longer considered an ASD.

WebMD Medical Reference Reviewed by Roy Benaroch, MD on November 19, 2016

Sources

SOURCES:

National Institute of Mental Health: "Autism Spectrum Disorders."

National Institute of Neurological Disorders and Stroke: "Asperger Syndrome Fact Sheet."

Journal of the American Academy of Child & Adolescent Psychiatry: “Specifying PDD-NOS: A Comparison of PDD-NOS, Asperger Syndrome, and Autism.”

Psychiatric Clinics of North America: “The autistic spectrum: subgroups, boundaries, and treatment.”

Spectrum: “Reclassification of Rett syndrome diagnosis stirs concerns.”

Rettsyndrome.org: “What is Rett Syndrome?”

Autism Speaks: “Asperger Syndrome,” “About Autism: Why Was My Child Diagnosed with Autism? And What Does It Mean?”

Centers for Disease Control: “Facts About ASD.”

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