Autism Spectrum Disorder (ASD) refers to a group of developmental disabilities – including classic autism, Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), and Asperger’s Syndrome – that affect a person’s ability to understand what they see, hear, and otherwise sense. It is a brain disorder that impacts communication, social interaction, and behavior.

Individuals with ASD typically have difficulty understanding verbal and nonverbal communication and learning appropriate ways of relating to other people, objects, and events. No two people with ASD are the same. As its name implies, ASD is a spectrum disorder that affects individuals differently and with varying degrees of severity. Additionally, ASD is often found in combination with other disabilities.
 

What Causes ASD?

Although it was first identified in 1943, to this day no one knows exactly what causes ASD. However, research to discover its cause is ongoing. Many researchers believe that there is a strong genetic component. Some research suggests a physical problem that affects the parts of the brain that process language and information; other research points to an imbalance of brain chemicals. A variety of possible external or environmental triggers are also being studied. It is possible that ASD is caused by a combination of several factors.
 

Signs and Symptoms

People with ASD may have problems with social, behavioral, and communication skills. They might repeat behaviors and might not understand change in their daily activities. Many people with ASD also have different ways of learning, paying attention, or reacting to things.

A person with ASD might:

• have severe language deficits or differences;
• talk about or show interest in a restricted range of topics;
• not point at objects to show interest (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 other people talk to them but respond to other sounds;
• repeat or echo words or phrases said to them, or repeat words or phrases in place of normal language (echolalia);
• have trouble expressing their needs using typical words or motions;
• laugh, cry, or show distress for no apparent reason;
• 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;
• be oversensitive or under-sensitive to pain; and
• lose skills they once had (for instance, stop saying words they were once using).