CLINICAL DESCRIPTION OF THE PERVASIVE DEVELOPMENTAL DISORDERS
Autism (also sometimes called Infantile Autism, Early Infantile Autism, Autistic Disorder, or Kanner's syndrome) was first described by Dr. Leo Kanner in 1943, who reported on eleven children who exhibited an apparently congenital lack of interest in other people. In contrast, these children were highly interested in unusual aspects of the inanimate environment. For several decades after the initial description of autism, research on this and related conditions was impeded by a lack of consensus on aspects of syndrome definition, as well as by assumptions of continuity between these conditions and severe forms of mental illness in adults, particularly schizophrenia. The idea that autism was the earliest form of schizophrenia reflected an awareness of the severity of both conditions, the then-current extremely broad views of schizophrenia, and Kanner's use of the word autism, which had previously been used to describe the self-centered quality of thinking in schizophrenia, not a relative absence of social relatedness. It took many years before researchers and clinicians could be sure that autism and schizophrenia were indeed different conditions. As part of this confusion, some early clinicians thought that perhaps autism could be caused by negative experience; we now know that this is not in fact the case. Autism is associated with various kinds of neurobiological symptoms, which range from the persistence of unusual reflexes, the high rates of seizure disorder in persons with autism (25 percent in most cases), and increased frequency of the condition in identical twins. Autism has its origins in the first weeks or months of life. It is characterized by marked problems in social interaction (autism), as well as by delayed and deviant communication development (speech is absent in about 50 percent of cases) and various other behaviors which are usually subsumed in the term 'insistence on sameness.' Such behaviors include stereotyped motor behaviors (hand flapping, body rocking), insistence on sameness and resistance to change. Both categorical and dimensional approaches to diagnosis have been used, as for instance in the DSM-IV Worldwide Field Trial. Many individuals with autism exhibit mental retardation on the basis of their full-scale (or averaged) IQ score; however, unlike most people with primary mental retardation, those with autism often have marked scatter in their development, so that some aspects of the IQ, particularly nonverbal skills, may be within the normal range. Autism is sometimes observed along with other medical and psychiatric conditions such as Fragile X syndrome.