Autism spectrum disorder
A spectrum of developmental disorders that includes autism, asperger syndrome, and rett syndrome. Signs and symptoms include poor communication skills, defective social interactions, and repetitive behaviors.
Autism spectrum disorder (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:
- 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. 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:
- Intellectual problems, including problems with reasoning or memory
- Language problems, such as problems with speech
- Another medical or genetic condition that is related to or contributes to autism, such as seizures or Fragile X syndrome
In May 2013, a revised version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the guidelines health care providers use to diagnose different mental health conditions, was released. The DSM-5 made significant changes to how autism is classified and diagnosed.
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 autistic disorder ("classic" autism), Asperger syndrome (which usually involved milder symptoms, mostly related to social behaviors), childhood disintegrative disorder (in which a child would develop normally for several months or years, then would lose skills related to language, movement and coordination, and other brain functions), and pervasive developmental disorder not otherwise specified (PDD-NOS, or "atypical" autism, which 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.
What are the symptoms of autism?
The symptoms of one person with autism can be very different from the symptoms of another person with autism. Health care providers think of autism as a spectrum disorder—which means that there is a range of similar features in different people with the disorder.
One person with autism may have mild symptoms, while another may have more serious symptoms, but they both have autism spectrum disorder (ASD).
Despite the range of possible symptoms, there are certain actions and behaviors that are common in ASD and could signal that a child is on the autism spectrum. Parents and caregivers who notice these "red flags" should speak to their child's health care provider about autism and screening the child for ASD.
In general, the main signs and symptoms of ASD relate to:
- Communication and interactions with other people
- Routines or repetitive behaviors, sometimes called stereotyped (pronounced STER-ee-uh-tahypt) behaviors
Health care providers organize some noticeable symptoms of autism into "red flags" to help parents and caregivers know what to look for as children grow and develop. These red flags are listed below.
Red Flags for ASD
- Does not respond to his/her name by 12 months of age
- Cannot explain what he/she wants
- Doesn't follow directions
- Seems to hear sometimes, but not other times
- Doesn't point or wave "bye-bye"
- Used to say a few words or babble, but now does not
- Doesn't smile when smiled at
- Has poor eye contact
- Seems to prefer to play alone
- Gets things for him/herself only
- Is very independent for his/her age
- Seems to be in his/her "own world"
- Seems to tune people out
- Is not interested in other children
- Doesn't point out interesting objects by 14 months of age
- Doesn't like to play "peek-a-boo"
- Doesn't try to attract his/her parent's attention
- Gets "stuck" doing the same things over and over and can't move on to other things
- Shows unusual attachments to toys, objects, or routines (for example, always holding a string or having to put on socks before pants)
- Spends a lot of time lining things up or putting things in a certain order
- Repeats words or phrases (sometimes called echolalia [pronounced ek-oh-LEY-lee-uh])
You can find age-specific milestones on the Centers for Disease Control and Prevention website Learn the Signs. Act Early. If your child does not meet developmental milestones, talk to his or her health care provider about screening for ASD.
Note about these red flags:
- Some of these red flags apply only at certain ages, so consider what is typical for other children your child's age.
- Some red flags are more strongly associated with autism than others.
- If your child shows any red flags for autism, talk to his or her health care provider.
When do children usually show symptoms of autism?
The behavioral symptoms of autism spectrum disorder (ASD) often appear early in development.1 Many children show symptoms of autism by 12 months to 18 months of age or earlier. Some early signs of autism include:
- Problems with eye contact
- No response to his or her name
- Problems following another person's gaze or pointed finger to an object (or "joint attention")
- Poor skills in pretend play and imitation
- Problems with nonverbal communication
Many parents are not aware of these "early" signs of autism and don't start thinking about autism until their children do not start talking at a typical age.
Most children with autism are not diagnosed until after age 3, even though health care providers can often see developmental problems before that age.
Research shows that early detection and early intervention greatly improve outcomes,10 so it's important to look for these symptoms when a child is as young as possible.
Some children with autism regress, meaning they stop using language, play, or social skills that they've already learned. This regression may happen between ages year and 2 years. It might happen earlier for some social behaviors, such as looking at faces and sharing a smile. Researchers don't know why some children regress into autism or which children are likely to regress.
There also may be early biological signs of ASD. Recent studies have shown that:
- People with autism have unique brain activity, structures, and connections even at very young ages.
- There are differences in brain growth in ASD as early as 6 months of age.
What causes autism?
Scientists don't know exactly what causes autism spectrum disorder (ASD).
Autism was first described in the 1940s, but very little was known about it until the last few decades. Even today, there is a great deal that we don't know about autism.
Because the disorder is so complex and no two people with autism are exactly alike, there are probably many causes for autism. It is also likely that there is not a single cause for autism, but rather that it results from a combination of causes.
Scientists are studying some of the following as possible causes of or contributors to ASD.
Genes: Bits of DNA that carry instructions for "building" your body.
Chromosomes: Packages of DNA and genes in the cells of the body.
A great deal of evidence supports the idea that genes are one of the main causes of or a major contributor to ASD. More than 100 genes on different chromosomes may be involved in causing ASD, to different degrees.
Many people with autism have slight changes, called mutations, in many of these genes. However, the link between genetic mutations and autism is complex:
- Most people with autism have different mutations and combinations of mutations. Not everyone with autism has changes in every gene that scientists have linked to ASD.
- Many people without autism or autism symptoms also have some of these genetic mutations that scientists have linked to autism.
This evidence means that different genetic mutations probably play different roles in ASD. For example, certain mutations or combinations of mutations might:
- Cause specific symptoms of ASD
- Control how mild or severe those symptoms are
- Increase susceptibility to autism. This means someone with one of these gene mutations is at greater risk for autism than someone without the mutation.
If someone is susceptible to ASD because of genetic mutations, then certain situations might cause autism in that person.
For instance, an infection or contact with chemicals in the environment could cause autism in someone who is susceptible because of genetic mutations.1 However, someone who is genetically susceptible might not get an ASD even if he or she has the same experiences.
Researchers are also looking into biological factors other than genes that might be involved in ASD. Some of these include:
- Problems with brain connections
- Problems with growth or overgrowth in certain areas of the brain
- Problems with metabolism (the body's energy production system)
- Problems in the body's immune system, which protects against infections.
What are the treatments for autism?
There is currently no one standard treatment for autism spectrum disorder (ASD).
Many people with ASD benefit from treatment, no matter how old they are when they are diagnosed. People of all ages, at all levels of ability, can often improve after well-designed interventions.
But there are many ways to help minimize the symptoms and maximize abilities. People who have ASD have the best chance of using all of their abilities and skills if they receive appropriate therapies and interventions.
The most effective therapies and interventions are often different for each person. However, most people with ASD respond best to highly structured and specialized programs.1 In some cases, treatment can help people with autism to function at near-normal levels.
Research shows that early diagnosis and interventions, such as during preschool or before, are more likely to have major positive effects on symptoms and later skills. Read more about early interventions for autism.
Because there can be overlap in symptoms between ASD and other disorders, such as attention deficit hyperactivity disorder (ADHD),2 it's important that treatment focus on a person's specific needs, rather than the diagnostic label.
Select the links for more information on each type of treatment for ASD.
- Behavioral management therapy
- Cognitive behavior therapy
- Early intervention
- Educational and school-based therapies
- Joint attention therapy
- Medication treatment
- Nutritional therapy
- Occupational therapy
- Parent-mediated therapy
- Physical therapy
- Social skills training
- Speech-language therapy
If you have a question about treatment, talk to a health care provider who specializes in caring for people with ASD.