The impairment in communication is also marked and sustained and affects both verbal and nonverbal skills. There may be delay in, or total lack of, the development of spoken language. In individuals who do speak, there may be marked impairment in the ability to initiate or sustain a conversation with others or a stereotyped and repetitive use of language or idiosyncratic language. There may also be a lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level. A disturbance in the comprehension of language may be evidenced by an inability to understand simple questions, directions, or jokes.
Imaginative play is often absent or markedly impaired.
These individuals also tend not to engage in the simple imitation games or routines of infancy or early childhood or do so only out of context or in a mechanical way. The disturbance is not better accounted by Rett's Disorder or Childhood Disintegrative Disorder. Recent studies estimate that as many as 14 children out of 10,000 may have autism or a related condition. About 125,000 Americans are affected by these disorders, and nearly 4,000 families across the country have two or more children with autism. Three times as many boys as girls have autism.