Pervasive developmental disorders are characterized by disordered thinking and difficulty understanding and using language, understanding the feelings of others, or more generally, understanding the world around them. Such disorders are often associated with severe learning difficulties and impaired intelligence. The most common pervasive developmental disorders are autism, Asperger's disorder and Rett's disorder.
Autism, the most common of the pervasive developmental disorders, is characterized by severely compromised ability to engage in, and by a lack of interest in, social interactions. It has roots in both structural brain abnormalities and genetic predispositions, according to family studies and studies of brain anatomy. Because autism is a severe, chronic developmental disorder, which results in significant lifelong disability, the goal of treatment is to promote the child’s social and language development and minimize behaviors that interfere with the child’s functioning and learning. Intensive, sustained special education programs and behavior therapy early in life can increase the ability of the child with autism to acquire language and ability to learn. Special education programs in highly structured environments appear to help the child acquire self-care, social, and job skills.
The search for genes that predispose to autism is considered an extremely high research priority for the National Institute of Mental Health (NIMH, 1998). Although the reported association between autism and obstetrical hazard may be due to genetic factors, there is evidence that several different causes of toxic or infectious damage to the central nervous system during early development also may contribute to autism. Autism has been reported in children with fetal alcohol syndrome, in children who were infected with rubella during pregnancy, and in children whose mothers took a variety of medications that are known to damage the fetus.