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.

Signs and Symptoms

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

There is currently no cure for ASD. However, research shows that early intervention treatment services can improve a child’s development. Early intervention services help children from birth to 3 years old (36 months) learn important skills. Services can include therapy to help the child talk, walk, and interact with others. Therefore, it is important to talk to your child’s doctor as soon as possible if you think your child has ASD or other developmental problem.

Even if your child has not been diagnosed with an ASD, he or she may be eligible for early intervention treatment services. The Individuals with Disabilities Education Act (IDEA)  says that children under the age of 3 years (36 months) who are at risk of having developmental delays may be eligible for services. These services are provided through an early intervention system in your state. Through this system, you can ask for an evaluation.

In addition, treatment for particular symptoms, such as speech therapy for language delays, often does not need to wait for a formal ASD diagnosis.

Causes and Risk Factors

We do not know all of the causes of ASD. However, we have learned that there are likely many causes for multiple types of ASD. There may be many different factors that make a child more likely to have an ASD, including environmental, biologic and genetic factors.

• Most scientists agree that genes are one of the risk factors that can make a person more likely to develop ASD.
• Children who have a sibling with ASD are at a higher risk of also having ASD. 
• ASD tends to occur more often in people who have certain genetic or chromosomal conditions, such as fragile X syndrome  or tuberous sclerosis.
• When taken during pregnancy, the prescription drugs valproic acid and thalidomide have been linked with a higher risk of ASD.
• There is some evidence that the critical period for developing ASD occurs before, during, and immediately after birth. 
• Children born to older parents are at greater risk for having ASD.