Symptoms of the condition are evident either from birth or may begin appear after a period of normal development, but definitely by the time the child is two and a half years old. Autism is known as a 'spectrum disorder,' because the severity of symptoms ranges from a mild learning and social disability to a severe impairment, with multiple problems and highly unusual behavior. The disorder may occur alone, or with accompanying problems such as mental retardation or seizures. Autism is not a rare disorder, being the third most common developmental disorder, more common than Down's Syndrome . Typically, about 20 in a population of 10,000 people will be autistic or have autistic symptoms.
Autism is found throughout the world, in families of all economic, social, and racial backgrounds.
Doctors, politicians, and rickshaw drivers alike all have autistic children. A child with high functioning autism may have a normal or high I.Q., be able to attend a regular school and hold a job later in life. However, this person may have difficulty expressing himself and may not know how to mix with other people. Moderately and more seriously affected children with autism will vary tremendously. Some autistic children do not ever develop speech, while others may develop speech but still have difficulty using language to communicate.