In the five decades since autism was first described, much has changed in the diagnosis and treatment of the syndrome, observes B. J. Freeman, Ph.D., professor of medical psychology at the UCLA Neuropsychiatric Institute and Hospital. The definition is based on assumptions and facts that contradict some previously held beliefs about autism. The diagnosis of the disorder is based on the presence or absence of a triad of symptoms in communication skills, social skills and restricted repertoire of interest. Like all syndromes, autism is assumed to be composed of many subtypes, each with different etiologies and possible treatments. Anything that can cause damage to the parts of the brain that produce these symptoms is called autism.
Autism is a spectrum disorder .
In the triad of symptoms, there are many possible combinations. For example, you can have a very high IQ and be severely socially impaired. Autism is a developmental diagnosis. Expression of the symptoms varies with both the chronological age, mental age and developmental level of the person. Symptoms may fluctuate, abate, change and even disappear, but once autistic, that person is always autistic.