About Autism

What is Autism?

Autism, or autism spectrum disorder ASD, refers to a range of conditions characterized by challenges with social skills, repetitive behaviors, speech and nonverbal communication, as well as by unique strengths and differences. We now know that there is not one autism but many types, caused by different combinations of genetic and environmental influences. The term “spectrum” reflects the wide variation in challenges and strengths possessed by each person with autism. Autism’s most-obvious signs tend to appear between 2 and 3 years of age. In some cases, it can be diagnosed as early as 18 months. Some developmental delays associated with autism can be identified and addressed even earlier. Autism Speaks urges parents with concerns to seek evaluation without delay, as early intervention can improve outcomes.

Possible signs of autism at any age


1
Avoids eye contact and prefers to be alone
2
Struggles with understanding other people’s feelings
3
Remains nonverbal or has delayed language development
4
Repeats words or phrases over and over (echolalia)
5
Gets upset by minor changes in routine or surroundings
6
Has unusual and often intense reactions to sounds, smells, tastes, textures, lights and/or colors
7
Performs repetitive behaviors such as flapping, rocking or spinning
8
Has highly restricted interests
We know that there’s no one cause of autism. Research suggests that autism develops from a combination of genetic and nongenetic, or environmental, influences. These influences appear to increase the risk that a child will develop autism. However, it’s important to keep in mind that increased risk is not the same as cause. For example, some gene changes associated with autism can also be found in people who don’t have the disorder. Similarly, not everyone exposed to an environmental risk factor for autism will develop the disorder. In fact, most will not.

What causes Autism?

Research tells us that autism tends to run in families. Changes in certain genes increase the risk that a child will develop autism. If a parent carries one or more of these gene changes, they may get passed to a child (even if the parent does not have autism). Other times, these genetic changes arise spontaneously in an early embryo or the sperm and/or egg that combine to create the embryo. Again, the majority of these gene changes do not cause autism by themselves. They simply increase risk for the disorder.
Research also shows that certain environmental influences may further increase – or reduce – autism risk in people who are genetically predisposed to the disorder. Importantly, the increase or decrease in risk appears to be small for any one of these risk factors:
Increased risk:
  • Advanced parent age (either parent)
  • Pregnancy and birth complications (e.g. extreme prematurity [before 26 weeks], low birth weight, multiple pregnancies [twin, triplet, etc.])
  • Pregnancies spaced less than one year apart
Decreased risk:
  • Prenatal vitamins containing folic acid, before and at conception and through pregnancy
No effect on risk:
  • Vaccines Each family has a unique experience with an autism diagnosis, and for some it corresponds with the timing of their child’s vaccinations. At the same time, scientists have conducted extensive research over the last two decades to determine whether there is any link between childhood vaccinations and autism. The results of this research is clear: Vaccines do not cause autism. The American Academy of Pediatrics has compiled a comprehensive list of this research. You can view and download the list here.
How do these genetic and nongenetic influences give rise to autism? Most appear to affect crucial aspects of early brain development. Some appear to affect how brain nerve cells, or neurons, communicate with each other. Others appear to affect how entire regions of the brain communicate with each other. Research continues to explore these differences with an eye to developing treatments and supports that can improve quality of life.