Overview
Autism spectrum disorder is a condition related to brain development that affects how people see others and socialize with them. This causes problems in communication and getting along with others socially. The condition also includes limited and repeated patterns of behavior. The term "spectrum" in autism spectrum disorder refers to the wide range of symptoms and the severity of these symptoms.
Autism spectrum disorder includes conditions that were once thought to be separate — autism, Asperger's syndrome, childhood disintegrative disorder and a form of widespread developmental disorder that isn't specified.
Autism spectrum disorder begins in early childhood. Over time, it can cause difficulty functioning in society. For example, people with autism spectrum disorder may have problems being social or when in school or at work. Often children show symptoms of autism within the first year of life. A small number of children with the condition appear to develop as expected in the first year. Then between 18 and 24 months of age, they may lose some skills and develop autism symptoms.
There is no cure for autism spectrum disorder. But getting treatment early, during the preschool years, can make a big difference in the lives of many children with the condition.
Symptoms
Some children show signs of autism spectrum disorder in early infancy, such as less eye contact, not responding to their names or not being interested in caregivers. Other children may not develop as expected for the first few months or years of life. Then they suddenly become withdrawn or aggressive or lose the language skills they had before. Signs usually are seen by ages 2 to 3 years old.
Some people in the mild range on the autism spectrum may have more symptoms that aren't noticed early on. They may not be diagnosed until middle to late childhood, when there is a greater need to communicate and be social. Sometimes a diagnosis is made for the first time in adulthood, though symptoms were likely present during childhood.
Each child with autism spectrum disorder is likely to have a unique pattern of behavior that depends on whether symptoms are mild, moderate or severe.
Some children with autism spectrum disorder have trouble learning, and some have signs of lower than usual intelligence. Other children with the condition have usual to high intelligence. These children learn quickly but have trouble communicating, applying what they know in everyday life and adjusting to social situations.
Because each child can have a unique mix of symptoms, sometimes it can be hard to tell how severe the condition is. It's generally based on how severe the symptoms are and how much those symptoms affect a child being able to function.
Below are some common signs shown by people who have autism spectrum disorder.
Social communication and interaction
People with autism spectrum disorder may have problems getting along with others and communicating. They may have a mix of these and other symptoms:
- Don't respond to their name, or they don't seem to hear at times.
- Don't want to be cuddled or held and prefer to play alone, retreating into their own worlds.
- Have poor eye contact and have no expression on their faces.
- Don't speak or have delayed speech or lose the ability to say words or sentences as they could before.
- Can't start a conversation or keep one going, or only start one to make requests or label items.
- Speak with an unusual tone or rhythm and may use a singsong voice or robotlike speech.
- Repeat words or phrases word for word but don't know how to use them.
- Don't seem to understand simple questions or directions.
- Don't show emotions or feelings and don't seem to be aware of how others feel.
- Don't point at or bring objects to share interest.
- Are passive, aggressive or disruptive when interacting with others.
- Have a hard time figuring out what it means when people have different looks on their faces, position their bodies differently or speak in different tones of voice.
Patterns of behavior
People with autism spectrum disorder may have limited, repetitive patterns of behavior, interests or activities, including a mix of these and other signs:
- Make the same movement over and over again, such as rocking, spinning or hand-flapping.
- Do activities where they could hurt themselves, such as biting or head-banging.
- Create specific routines or rituals and become upset at even small changes.
- Aren't coordinated and may be clumsy, or they move in patterns that aren't usual, such as walking on toes.
- Have unusual, stiff or exaggerated body language.
- Are fascinated by details of an object, such as the spinning wheels of a toy car, but they don't know what the object is for or how it works.
- Are sensitive to light, sound or touch but may not be affected by pain or temperature.
- Don't mimic others or take part in make-believe play.
- Fixate on an object or activity with unusual intensity or focus.
- Prefer specific foods, such as eating only a few foods or not wanting to eat foods with certain textures.
As they get older, some children with autism spectrum disorder interact more with others and show fewer disturbances in behavior. Some, usually those with the least severe problems, eventually may lead typical or nearly typical lives. But others continue to have trouble with language or social skills. And the teenage years can bring more behavioral and emotional challenges.
When to see a doctor
Babies develop at their own pace, and many don't follow exact timelines found in some parenting books. But children with autism spectrum disorder usually show some signs of delayed development before they're 3 years old. Signs of autism spectrum disorder often appear early in development when there are obvious delays in language skills and social interactions.
If you're concerned about your child's development or think that your child may have autism spectrum disorder, talk with a healthcare professional about your concerns. Your healthcare professional may recommend developmental tests to figure out if your child has delays in learning, thinking, language or social skills that point to autism spectrum disorder or another type of developmental condition.
Causes
Autism spectrum disorder has no single known cause. Since the condition is complex and symptoms and severity vary, there could be many causes. Both genetics and the environment may play a role.
- Genetics. Several genes seem to be involved in autism spectrum disorder. For some children, autism spectrum disorder can be related to a genetic condition, such as Rett syndrome or fragile X syndrome. For other children, genetic changes, also known as mutations, may raise the risk of autism spectrum disorder. Still other genes may affect the way that the brain develops or brain cells communicate. Or those genes may affect how severe symptoms are. While some genetic changes seem to be inherited, others aren't.
- Environmental factors. Researchers are exploring whether factors such as viral infections, medicines, complications during pregnancy or air pollutants play a role in causing autism spectrum disorder.
No link between vaccines and autism spectrum disorder
One of the greatest controversies in autism spectrum disorder centers on whether there is a link between the condition and childhood vaccines. Many well-done research studies show no link between autism spectrum disorder and any vaccines. In fact, the original study that started the debate years ago was retracted due to poor design and questionable research methods.
When your child doesn't get vaccines, your child and other children could catch and spread viruses that cause serious diseases. These diseases include whooping cough, also known as pertussis, as well as measles, mumps and others.
Risk factors
The number of children diagnosed with autism spectrum disorder is rising. It isn't clear whether this is due to better ways to diagnose and report the condition, a real increase in the number of children with the condition, or both.
Autism spectrum disorder affects children of all races and nationalities. But certain factors raise a child's risk, including:
- Your child's sex. Boys are about four times more likely to be diagnosed with autism spectrum disorder than girls are. While boys may get autism spectrum disorder more often than girls, it's possible that some girls aren't diagnosed.
- Family history. Families who have one child with autism spectrum disorder have a higher risk of having another child with the condition. Sometimes parents or relatives of a child with autism spectrum disorder may have minor problems being social or communicating, or they may show certain behaviors typical of the condition.
- Other conditions. Children with certain medical conditions have a higher risk of autism spectrum disorder or symptoms similar to autism. Examples include fragile X syndrome, an inherited condition that causes intellectual disability; tuberous sclerosis, a condition in which benign tumors develop in the brain; and Rett syndrome, a genetic condition that almost always occurs in girls and causes slowing of head growth, intellectual disability and loss of purposeful hand use.
- Early birth. Babies born before 26 weeks of a parent's pregnancy may have a higher risk of autism spectrum disorder.
- Parents' ages. There may be a connection between children born to older parents and autism spectrum disorder. But more research is needed to show this link.
Complications
Because people with autism spectrum disorder often have a hard time interacting socially, communicating or behaving, this can lead to problems with:
- School and learning.
- Getting a job.
- Not being able to live on their own.
- Being isolated socially.
- Stress within the family.
- Being a victim and being bullied.
Prevention
There's no known way to prevent autism spectrum disorder. But many studies have been done to see if taking folic acid and other vitamins before and during pregnancy can lower the risk of having a baby with autism spectrum disorder. A review of studies on what are known as prenatal vitamins shows no clear answer. This is due to the quality of the research. More high-quality studies are needed.
Getting diagnosed and treated early is most helpful in improving behavior, skills and language development. But getting treatment is helpful at any age. Though children usually don't outgrow autism spectrum disorder symptoms, they may learn to function well.