Autism Classification

Autism is a term commonly used to pertain to all disorders under the Autism Spectrum Disorder Umbrella. This misconception about autism often leads to stereotyping. As of 2010, there are 5 classifications of autism: Autistic disorder, Asperger Syndrome, Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS), Childhood Disintegrative Disorder (CDD) and Rett Syndrome (NICHD, 2010).

Archive correction — October 12, 2026: the five-category, mild-to-severe ranking below is not the current diagnostic framework. DSM-5 brought autistic disorder, Asperger’s disorder, childhood disintegrative disorder and PDD-NOS into one autism spectrum disorder diagnosis. Rett syndrome is a separate neurological and developmental condition, not a severe form of autism. The original text is retained as a historical record, not as current diagnostic guidance.

Autistic Disorder

Autistic Disorder is commonly called “classic autism.” It is a neurological and developmental disorder that is typically seen during the first three years of life. Individuals diagnosed with this disorder normally manifest developmental delays in communication, social and behavior skills. They often display characteristics that set them apart from others such as the difficulty in engaging in social relationships and an obsession with behavior patterns.

Asperger Syndrome

Asperger Syndrome is identified as the mildest of all disorders under the ASD umbrella, specifically because the symptoms present in this disorder are more manageable and individuals with Asperger’s usually have a better prognosis with the help of constant and proper therapies. People with Asperger Syndrome often do not have significant language delay compared to others in the spectrum. They have the urge to engage in social interactions but may lack the ability to appropriately initiate one. They also manifest a difficulty in motor coordination such as walking, running or anything that involves refined motor skills.

Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS)

This disorder under the ASD umbrella classifies individuals that exhibit some symptoms, but not all, that are associated with classic autism. Their symptoms are usually not enough to completely classify them under a specific disorder set by the experts. Some symptoms may be mild and some symptoms may be worse than others in the spectrum.

Childhood Disintegrative Disorder (CDD)

In CDD, a child develops typically for at least the first two years and then, before age 10 (most often between ages 3 and 4), loses skills already learned. Then over the course of months children start to manifest a variety of problems such as language regression, motor and social skills.

Rett’s Syndrome

Rett syndrome is a separate genetic neurological condition, almost always in girls, caused in most cases by changes in the MECP2 gene. It is not a form of autism, though young children with Rett syndrome can go through a period that looks like autism. It manifests symptoms such as loss of motor and communication skills after a period of normal development. Children affected by this disorder often lose their ability to speak even though they have normally used speech and language skills normally in the past. They often engage in stereotype hand movements such as wringing and clapping (NICHD, 2010).

Autism Spectrum Disorders mean that no two individuals diagnosed with autism will manifest the same exact symptoms and have the same level of severity. Common autism symptoms such as communication, social and behavioral difficulties will be present in all types of autism but will differ in the manner and severity.

References:

National Institute of Child Health and Human Development. nichd.nih.gov. Ausitm Spectrum Disorders. Retrieved May 11, 2011 from http://www.nichd.nih.gov/health/topics/asd.cfm

US National Library of Medicine and National Institute of Health. nlm.nih.gov. Childhood Disintegrative Disoder. Retrieved May 11, 2011 from http://www.nlm.nih.gov/medlineplus/ency/article/001535.htm

National Institute of Child Health and Human Development. nichd.nih.gov. Rett Syndrome. Retrieved May 11, 2011 from http://www.nichd.nih.gov/health/topics/rett_syndrome.cfm

Copyright © by Special Learning Inc. All right reserved.

No part of this article may be reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles and reviews. For information, contact Special Learning Inc., at: contact@special-learning.com