The brain disorder autism begins in early childhood and persists throughout adulthood affecting three crucial areas of development: verbal and nonverbal communication, social interaction, and creative or imaginative play.

Autism is the most common of a group of conditions called pervasive developmental disorders (PDDs). PDDs involve delays in many areas of childhood development. The first signs of autism are usually noticed by the age of three. Many individuals who are autistic also develop epilepsy, a brain disorder that causes convulsive seizures, as they approach adulthood. Other characteristics may include repetitive and ritualistic behaviors, hand flapping, spinning or running in circles, excessive fears, self-injury such as head banging or biting, aggression, insensitivity to pain, temper tantrums, and sleeping and eating disturbances. Autistic individuals live a normal life span, but most require lifelong care and supervision.

Leo Kanner first identified autism in 1943 when he described 11 self-absorbed children who had "autistic disturbances of affect contact." At first, autism was thought to be an attachment disorder resulting from poor parenting. This has been proved to be a myth. While the cause remains a mystery, most specialists now view autism as a brain disorder that makes it difficult for the person to process and respond to the world. Autism has been observed in several members of the same families. Therefore, many scientists believe that, at least in some individuals, autism may be genetic. Scientists have identified some genes as playing a possible role in the development of autism.

Some report that the Lindamood-Bell-Autism Learning Processes are helpful in treating persons with autism.