Learn About Autism Spectrum Disorder

Click on the tabs to expand facts about Autism Spectrum Disorders (ASDs).

Autism is the fastest growing developmental disability in the United States.

Autism spectrum disorder (ASD) is a developmental disability  that can cause significant social, communication and behavioral challenges. There is often nothing about how people with ASD look that sets them apart from other people, but people with ASD may communicate, interact, behave, and learn in ways that are different from most other people. The learning, thinking, and problem-solving abilities of people with ASD can range from gifted to severely challenged. Some people with ASD need a lot of help in their daily lives; others need less.

A diagnosis of ASD now includes several conditions that used to be diagnosed separately: autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), and Asperger syndrome. These conditions are now all called autism spectrum disorder.

— Centers for Disease Control

There is no known cause for autism, which is the primary reason we research. When we do know what causes autism, we will be able to better determine cures and treatments for autism-related symptoms.

We do know that brain scans of people with autism show differences in shape and structure compared to neurotypical people. This is why investigating how these differences appear through neurobiology and anatomy research (like what we do here at TARF) is so important.

Researchers share a number of theories, including links among genetics and environment.

Genetic Vulnerability

Some researchers have found that many families tend to have a pattern of autism or related disabilities, which supports the theory that ASDs may have a genetic basis. We have not found a specific gene that causes autism, but researchers are looking for irregular parts of genes that may be more succeptible to autism, and clusters of unstable genes that may interfere with brain development and “trigger” autism under certain conditions.

Still other researchers are investigating problems during pregnancy or delivery as well as environmental factors such as viral infections, metabolic imbalances and exposure to chemicals.

Environmental Factors

Environmental toxins (like mercury) are more prevalent than in the past, which research indicates may be contributing to the increasing prevalence of autism.

Individuals with autism (or those at-risk) may be especially vulnerable to such toxins, as their ability to metabolize and detoxify these exposures might be compromised.

The Bottom Line

Apart from differences in the brain, we do not have any definite answer for what causes autism and researchers are working everyday to understand the relationships between anatomy, heredity, genetics, medical problems, and environmental factors in causing autism spectrum disorders.

People with ASD often have problems with social, emotional, and communication skills. They might repeat certain behaviors and might not want change in their daily activities. Many people with ASD also have different ways of learning, paying attention, or reacting to things. Signs of ASD begin during early childhood and typically last throughout a person’s life.

Children or adults with ASD might:

  • not point at objects to show interest (for example, not point at an airplane flying over)
  • not look at objects when another person points at them
  • have trouble relating to others or not have an interest in other people at all
  • avoid eye contact and want to be alone
  • have trouble understanding other people’s feelings or talking about their own feelings
  • prefer not to be held or cuddled, or might cuddle only when they want to
  • appear to be unaware when people talk to them, but respond to other sounds
  • be very interested in people, but not know how to talk, play, or relate to them
  • repeat or echo words or phrases said to them, or repeat words or phrases in place of normal language
  • have trouble expressing their needs using typical words or motions
  • not play “pretend” games (for example, not pretend to “feed” a doll)
  • repeat actions over and over again
  • have trouble adapting when a routine changes
  • have unusual reactions to the way things smell, taste, look, feel, or sound
  • lose skills they once had (for example, stop saying words they were using)

— Centers for Disease Control


  • Each individual experiences the diagnosis differently.
  • There is no medical cure for autism.
  • Autism is the fastest growing developmental disability.
  • More kids will be diagnosed this year than pediatric AIDS, diabetes and cancer combined.


  • 1 in every 88 children has an autism spectrum disorder (1 in 54 in boys). New estimates suggest that 1 in 50 kids have an autism spectrum disorder now.
  • Autism is 4 times more prevalent in boys than girls.
  • 1 to 1.5 million people in the United States live with autism.
  • Families spend an average of $60,000 each year on autism treatment and therapies.
  • Average cost of autism over the lifespan is $3.2 million dollars.
  • The National Institute of Health set a funding budget of $30.86 billion dollars in 2012. Autism research received $169 million of this, which totals one-half of a percent (0.55%) of funding.

Autism Spectrum Disorders (ASDs) are not simple to diagnose, so it is extremely important to obtain a diagnosis from a qualified professional. Currently, there are no medical tests (like a blood test) that can detect autism, so professionals look at the child’s behavior and development to make a diagnosis.

Professionals equipped to diagnose ASDs include: developmental pediatricians, child neurologists, child psychologists or child psychiatrists. Parents often choose to consult with multiple professionals. You can read about the unique ways each professional can help you on our Early Intervention Services page.

A universal criterion to diagnose ASD does not yet exist and approaches may differ depending on the expert’s area of specialization. Physicians’ diagnoses usually rely on a combination of clinical observation, parental history and application of the DSM-IV criteria published by the American Psychiatric Association.

Elements you can expect to see covered in a physician’s evaluation include: medical, family and social history, physical exam, neurodevelopmental testing, reviews of outside clinical/academic records, and lab testing.

ASD can sometimes be detected at 18 months or younger. By age 2, a diagnosis by an experienced professional can be considered very reliable. However, many children do not receive a final diagnosis until they are much older, and this delay means that children with ASD might not get the early help they need.

If you think your child may have an Autism Spectrum Disorder:

Step 1:  Schedule an appointment with his/her primary care physician.

Explain that you would like to have your child evaluated for an Autism Spectrum Disorder, so that the receptionist can allocate an appropriate appointment time for you with the doctor.

Step 2: Understand that if your child does receive an autism diagnosis, Early Intervention Services can improve the prognosis of your child significantly.

Plan to be receptive of your physician’s advice and proactive toward helping your child get the services, if any, he/she needs to succeed.

Helpful Links

  • Identifying Language Delays: Describes the expected language milestones for developing babies and the signs of a possible language delay, which may be indicators of autism
  • Parent Manual: Outlines the basics of Evidence-Based Practice in autism, the different options for treatment, and facts about autism. Also provides research findings on autism and additional resources for families
  • Research Basics: A comprehensive outline of research findings in autism and a guide for understanding and utilizing research.
  • New Diagnosis, Now What?: A guide for parents trying to make sense of a new autism diagnosis. Provides information on the different treatment forms available, including lists of services the children and their families are legally entitled to.
theautismresearchfoundationLearn About Autism Spectrum Disorder