People on the autism spectrum have problems in three areas: social interaction, communicating with others, and behavioral challenges. Autism is referred to as an autism spectrum disorder (ASD) because people with autism have varying degrees of disability.
Each person with autism is different. They range from those with "classic" or "Kanner's" autism who have very little social or communication skills with severe behavioral problems, to those with Asperger;s syndrome who have difficulty socializing with others, but can hold jobs and maintain an independent life.
In the last 15 years autism has become the most commonly diagnosed childhood developmental disorder. According to the Centers for Disease Control Prevention in 2009, autism spectrum disorders now affect 1 in every 68 children in the United States. Statistics from the U.S. Department of Education and other government agencies indicate that autism diagnoses are increasing at the rate of 10% to 17% each year.
Autism can affect anyone, and is not based on ethnic, racial, or social backgrounds. The numbers of people diagnosed with autism is the same all around the world. Boys are four times more likely to have it than girls.
Because autism affects a person's development in several different areas (social, communication, behavior) it's important to have several interventions to address these challenges. Using a combination of therapies his is called a mosaic approach. It is not uncommon for a child with autism to receive behavioral therapy, speech therapy, occupational therapy, or any other combination of therapies at the same time.