Autism spectrum disorder

According to the Autism speaks: "Autism, or autism spectrum disorder (ASD), refers to a broad range of conditions characterized by challenges with social skills, repetitive behaviors, speech and nonverbal communication". As this is a spectrum, this can include conditions that have been previously categorized separately, notably: autism, Apserger's syndrome and childhood disintegrative disorder. 

Children who are affected by ASD have trouble communicating and interacting with others. They may not respond to their names or even look at other people. In severe cases, they may become aggressive or injure themselves. Adults who are affected by ASD can have difficulty functioning socially, but are more likely to be viewed as subclinically autistic. ASD cannot be cured, but there are many resources dedicated to helping those who are affected live a more "normal" life. 

Autism usually appears by age 3, mostly in boys. Studies in the USA and in the UK have established an incidence of about one autistic (psychotic) child per 2,500 births. Since true autism in this sense seems to represent about ten percent of children loosely called autistic, then around one child in 25,000 could be a realistic estimate of classical autism (including mild or subliminal or sub-clinical autism).

Autism rates reported to authorities in California nearly quadrupled between 1980 and 1994, to 208 cases per 100,000 children.

A 1997 study estimated that 80% of the 400,000 autistic people in the USA were also mentally retarded, while a few had IQ's in the genius range.