Autism Spectrum Disorder (ASD): The Basics
Learn the basics about autism spectrum disorder (ASD): what it is, signs and symptoms, strengths and abilities, risk factors, diagnosing ASD, the value of early intervention, and treatment and therapies that can help children and their families.
This article is adapted from information on the National Institute of Mental Health and the National Institute of Child Health and Human Development websites.
What is autism spectrum disorder?
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.
Children 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 children with the disorder.
Children with ASD often have these characteristics:
- Ongoing social problems that include difficulty communicating and interacting with others
- Repetitive behaviors as well as limited interests or activities
- Symptoms that typically are recognized in the first two years of life
- Symptoms that hurt the individual’s ability to function socially, at school or work, or other areas of life
Some children are mildly impaired by their symptoms, while others are severely disabled. Treatments and services can improve a person’s symptoms and ability to function. Families with concerns should talk to their pediatrician about what they’ve observed and the possibility of ASD screening.
According to the Centers for Disease Control and Prevention (CDC) about 1 in 59 children has been identified with some form of ASD.
What is the difference between Asperger syndrome and ASD?
In the past, Asperger syndrome and Autistic Disorder were separate disorders. They were listed as subcategories within the diagnosis of “Pervasive Developmental Disorders.” However, this separation has changed.
In the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Health Disorders, 5th Edition (DSM-5), children and adults with very severe symptoms of autism and people with milder symptoms who were previously diagnosed with Asperger syndrome now are considered to have the same diagnosis of Autism Spectrum Disorder.
However, if your child has already been diagnosed with Asperger syndrome, he or she should not have to be re-evaluated by a health care provider to receive a diagnosis of ASD.
Some people with the milder form of autism once known as Asperger syndrome consider the diagnostic label to be a part of their identity. There is nothing wrong with continuing to use this term to describe oneself or to identify with a peer group, even though the official diagnostic term has changed.
Signs and symptoms
ASD symptoms can vary greatly from person to person depending on the severity of the disorder. Symptoms may even go unrecognized for young children who have mild ASD or less debilitating handicaps.
Very early indicators include:
- no babbling or pointing by age 1
- no single words by age 16 months or two-word phrases by age 2
- no response to name
- loss of language or social skills previously acquired
- poor eye contact
- excessive lining up of toys or objects
- no smiling or social responsiveness
Later indicators include:
- impaired ability to make friends with peers
- impaired ability to initiate or sustain a conversation with others
- absence or impairment of imaginative and social play
- repetitive or unusual use of language
- abnormally intense or focused interest preoccupation with certain objects or subjects
- inflexible adherence to specific routines or rituals
Children with ASD may have other difficulties, such as being very sensitive to light, noise, clothing, or temperature. They may also experience sleep problems, digestion problems, and irritability.
Strengths and abilities
ASD is unique in that it is common for children with ASD to have many strengths and abilities in addition to challenges.
Strengths and abilities may include:
- Having above-average intelligence — the CDC reports that 46% of ASD children have above average intelligence
- Being able to learn things in detail and remember information for long periods of time
- Being strong visual and auditory learners
- Excelling in math, science, music, or art
Scientists don’t know the exact causes of ASD, but research suggests that genes and environment play important roles.
Risk factors include:
- Gender — boys are more likely to be diagnosed with ASD than girls
- Having a sibling with ASD
- Having older parents (a mother who was 35 or older, and/or a father who was 40 or older when the baby was born)
- Genetics — about 20% of children with ASD also have certain genetic conditions. Those conditions include Down syndrome, fragile X syndrome, and tuberous sclerosis among others.
In recent years, the number of children identified with ASD has increased. Experts disagree about whether this shows a true increase in ASD since the guidelines for diagnosis have changed in recent years as well. Also, many more parents and doctors now know about the disorder, so parents are more likely to have their children screened, and more doctors are able to properly diagnose ASD, even in adulthood.
Doctors diagnose ASD by looking at a child’s behavior and development. Young children with ASD can usually be reliably diagnosed by age two.
Older children and adolescents should be evaluated for ASD when a parent or teacher raises concerns based on watching the child socialize, communicate, and play.
Diagnosis in young children is often a two-stage process
Stage 1: General Developmental Screening During Well-Child Checkups
Every child should receive well-child check-ups with a pediatrician or an early childhood health care provider. The CDC recommends specific ASD screening be done at the 18- and 24-month visits.
Earlier screening might be needed if a child is at high risk for ASD or developmental problems. Those at high risk include children who:
- Have a sister, brother, or other family member with ASD
- Have some ASD behaviors
- Were born premature, or early, and at a low birth weight
Parents’ experiences and concerns are very important in the screening process for young children. Sometimes the doctor will ask parents questions about the child’s behaviors and combine this information with his or her observations of the child.
Children who show some developmental problems during this screening process will be referred for another stage of evaluation.
Stage 2: Additional Evaluation
This evaluation is with a team of doctors and other health professionals with a wide range of specialties who are experienced in diagnosing ASD. This team may include:
- A developmental pediatrician: a doctor who has special training in child development
- A child psychologist and/or child psychiatrist: a doctor who knows about brain development and behavior
- A speech-language pathologist: a health professional who has special training in communication difficulties.
The evaluation may assess:
- Cognitive level or thinking skills
- Language abilities
- Age-appropriate skills needed to complete daily activities independently, such as eating, dressing, and toileting
Because ASD is a complex disorder that sometimes occurs along with other illnesses or learning disorders, the comprehensive evaluation may include:
- Blood tests
- Hearing test
The outcome of the evaluation will result in recommendations to help plan for treatment.
Diagnosis in older children and adolescents
Older children whose ASD symptoms are noticed after starting school are often first recognized and evaluated by the school’s special education team. The school’s team may refer these children to a health care professional.
Parents may talk with a pediatrician about their child’s social difficulties including problems with subtle communication. These subtle communication issues may include understanding tone of voice, facial expressions, or body language. Older children may have trouble understanding figures of speech, humor, or sarcasm. Parents may also find that their child has trouble forming friendships with peers. The pediatrician can refer the child for further evaluation and treatment.
Early intervention for autism
Research shows that early diagnosis of and interventions for autism are more likely to have major long-term positive effects on symptoms and later skills. Autism spectrum disorder (ASD) can sometimes be diagnosed in children before they are 2 years of age. Some children with ASD whose development seems normal up to that point begin to regress just before or sometime during age 2 years.
Early intervention programs often include:
- Family training
- Speech therapy
- Hearing impairment services
- Physical therapy
- Nutrition services
Early interventions occur at or before preschool age, as early as 2 or 3 years of age. In this period, a young child's brain is still forming, meaning it is more "plastic" or changeable than at older ages. Because of this plasticity, treatments have a better chance of being effective in the longer term. Early interventions not only give children the best start possible, but also the best chance of developing to their full potential. The sooner a child gets help, the greater the chance for learning and progress. In fact, recent guidelines suggest starting an integrated developmental and behavioral intervention as soon as ASD is diagnosed or seriously suspected.
With early intervention, between 3% and 25% of children with autism make so much progress that they are no longer on the autism spectrum when they are older. Many of the children who later go off the spectrum have some things in common:
- Diagnosis and treatment at younger ages
- A higher intelligence quotient (IQ, a measure of thinking ability) than the average child with autism
- Better language and motor skills
Goals of early intervention
Early intervention programs help children gain the basic skills that they usually learn in the first 2 years of life, such as:
- Physical skills
- Thinking skills
- Communication skills
- Social skills
- Emotional skills
Find an early intervention program in your state
Each state has its own early intervention program for children from birth to age 2 years who are diagnosed with developmental delays or disabilities, including ASD. These programs are specified by Part C of Public Law 108-77: Individuals with Disabilities Education Improvement Act (IDEA). Some states also provide services for children who are at risk for developmental delays and disabilities.
To learn more about early intervention services:
Treatments and therapies
Early treatment for ASD and proper care can reduce children's difficulties while helping them learn new skills and make the most of their strengths.
The very wide range of issues facing those “on the spectrum” means that there is no single best treatment for ASD. Working closely with a doctor or health care professional is an important part of finding the right treatment program. There are many treatment options, social services, programs, and other resources that can help.
Because there can be overlap in symptoms between ASD and other disorders, such as attention deficit hyperactivity disorder (ADHD), it’s important that treatment focus on a child’s specific needs, rather than the diagnostic label.
Here are some basic tips:
- Keep a detailed notebook. Record conversations and meetings with health care providers and teachers. This information helps when its time to make decisions.
- Record doctors' reports and evaluations in the notebook. This information may help a child qualify for special programs.
- Contact the local health department, school, or autism advocacy groups to learn about their special programs.
- Talk with a pediatrician, school official, or physician to find a local autism expert who can help develop an intervention plan and find other local resources.
- Find an autism support group. Sharing information and experiences can help individuals with ASD and/or their caregivers learn about options, make decisions, and reduce stress.
A doctor may use medication to treat some difficulties that are common with ASD. With medication, a child with ASD may have fewer problems with:
- Repetitive behavior
- Attention problems
- Anxiety and depression
Learn more about the different types of treatment for ASD
More information from the National Institute of Child Health and Human Development (NICHD):
If you have a question about treatment, talk to a health care provider who specializes in caring for children with ASD.