Autism spectrum disorder (ASD) is a developmental disorder that affects communication and behavior. Although autism can be diagnosed at any age, it is said to be a “developmental disorder” because symptoms generally appear in the first two years of life.
Difficulty with communication and interaction with other people
Restricted interests and repetitive behaviors
Symptoms that hurt the person’s ability to function properly in school, work, and other areas of life
Autism is known as a “spectrum” disorder because there is wide variation in the type and severity of symptoms people experience. ASD occurs in all ethnic, racial, and economic groups. Although ASD can be a lifelong disorder, treatments and services can improve a person’s symptoms and ability to function. The American Academy of Pediatrics recommends that all children be screened for autism. All caregivers should talk to their doctor about ASD screening or evaluation.
Signs and Symptoms of ASD
People with ASD have difficulty with social communication and interaction, restricted interests, and repetitive behaviors. The list below gives some examples of the types of behaviors that are seen in people diagnosed with ASD. Not all people with ASD will show all behaviors, but most will show several.
Social communication / interaction behaviors may include:
Making little or inconsistent eye contact
Tending not to look at or listen to people
Rarely sharing enjoyment of objects or activities by pointing or showing things to others
Failing to, or being slow to, respond to someone calling their name or to other verbal attempts to gain attention
Having difficulties with the back and forth of conversation
Often talking at length about a favorite subject without noticing that others are not interested or without giving others a chance to respond
Having facial expressions, movements, and gestures that do not match what is being said
Having an unusual tone of voice that may sound sing-song or flat and robot-like
Having trouble understanding another person’s point of view or being unable to predict or understand other people’s actions
Restrictive / repetitive behaviors may include:
Repeating certain behaviors or having unusual behaviors. For example, repeating words or phrases, a behavior called echolalia
Having a lasting intense interest in certain topics, such as numbers, details, or facts
Having overly focused interests, such as with moving objects or parts of objects
Getting upset by slight changes in a routine
Being more or less sensitive than other people to sensory input, such as light, noise, clothing, or temperature
People with ASD may also experience sleep problems and irritability. Although people with ASD experience many challenges, they may also have many strengths, including:
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
Causes and Risk Factors
While scientists don’t know the exact causes of ASD, research suggests that genes can act together with influences from the environment to affect development in ways that lead to ASD. Although scientists are still trying to understand why some people develop ASD and others don’t, some risk factors include:
Having a sibling with ASD
Having older parents
Having certain genetic conditions—people with conditions such as Down syndrome, fragile X syndrome, and Rett syndrome are more likely than others to have ASD
Very low birth weight
Doctors diagnose ASD by looking at a person’s behavior and development. ASD can usually be reliably diagnosed by the age of two. It is important for those with concerns to seek out assessment as soon as possible so that a diagnosis can be made, and treatment can begin.
Diagnosis in Young Children
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 American Academy of Pediatrics recommends that all children be screened for developmental delays at their 9-, 18-, and 24- or 30-month well-child visits and specifically for autism at their 18- and 24-month well-child visits. Additional 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 family member with ASD, have some ASD behaviors, have older parents, have certain genetic conditions, or who were born at a very 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 those answers with information from ASD screening tools, and with his or her observations of the child. Read more about screening instruments on the Centers for Disease Control and Prevention (CDC) website.
Children who show developmental problems during this screening process will be referred for a second stage of evaluation.
Stage 2: Additional Evaluation
This second evaluation is with a team of doctors and other health professionals 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 has specialized training in brain development and behavior
A neuropsychologist—a doctor who focuses on evaluating, diagnosing, and treating neurological, medical, and neurodevelopmental disorders
A speech-language pathologist—a health professional who has special training in communication difficulties
The evaluation may assess:
Cognitive level or thinking skills
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:
The outcome of the evaluation will result in a formal diagnosis and recommendations for treatment.