What is ASD?
ASD is a complex neurological and developmental disorder that begins early in life and affects how a person acts and interacts with others, communicates, and learns. ASD affects the structure and function of the brain and nervous system. Because it affects development, ASD is called a developmental disorder. ASD can last throughout a person's life.
People with this disorder have problems with:1
- Communication and interaction with other people
- Restricted interests and repetitive behaviors
Different people with autism can have different symptoms. For this reason, autism is known as a spectrum disorder—which means that there is a range of similar features in different people with the disorder.1 This website uses "ASD" and "autism" to mean the same thing.
In giving a diagnosis of ASD, a health care provider will also specify whether the person also has:1
- Intellectual problems, including problems with reasoning or memory
- Language problems, such as problems learning to speak
- Another medical or genetic condition that is related to or contributes to autism, such as seizures or Fragile X syndrome
In May 2013, a new version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the common manual health care providers use to diagnose different mental health conditions, was released. The DSM-5 made significant changes to how autism is classified.
Now: Under the DSM-5, someone with more severe autism symptoms and someone with less severe autism symptoms both have the same disorder: ASD.
Then: In the previous version of the DSM, ASD was a category and there were four types of autism within the category. These were:2
Autistic disorder ("classic" autism)
- Asperger syndrome. This ASD usually involved milder symptoms, mostly related to social behaviors.
- Childhood disintegrative disorder. A child diagnosed with this condition would develop normally for several months or years, then would lose skills related to language, movement and coordination, and other brain functions.
- Pervasive developmental disorder not otherwise specified (PDD-NOS, or "atypical" autism). PDD-NOS included some, but not all, of the features of classic autism or Asperger syndrome.
Health care providers no longer use these terms to describe someone with ASD.
- Diagnostic and Statistical Manual of Mental Disorders, 5th Edition. (2013). American Psychiatric Association: Washington, DC. [top]
- Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Text Revision. (2000). American Psychiatric Association: Washington, DC. [top]