Autism Spectrum Disorders (ASD) are diagnosed on the basis of observation of behaviors and abilities. There is no specific medical test (like a blood test, CT scan or X-ray) that can diagnose autism. Under the current diagnostic system, listed in the Diagnostic and Statistical Manual IV-R (DSM-IV-R), www.cdc.gov/ncbddd/autism/hcp.dsm.html. ASDs fall under the broad category of Pervasive Developmental Disorders or PDD. Under this category, there are five different diagnoses: Asperger’s Syndrome, Classic Autism, Pervasive Developmental Disorder – Not Otherwise Specified, Rett’s Disorder and Childhood Disintegrative Disorder. Generally speaking, only the first three (Asperger’s, Classic Autism and PDD-NOS) are considered Autism Spectrum Disorders.
In order to receive a diagnosis, a person must exhibit deficiencies in each of three areas of functioning: social, communication and behavior. Differences in the level of deficiency in these three areas will result in different autism diagnoses.
All three of these domains are broad categories. For example, issues in communication can range from people with no or limited verbal language or communication skills to persons who have lots of language with large vocabularies but have difficulty in communicating their needs and desires to others. It is often helpful to picture ASD as a spectrum disorder, remembering that each person is unique and each person’s autism is unique. While it is important to obtain a correct diagnosis, it is more important to understand how autism presents itself within a specific person.