ABSTRACT
Autistic disorder is listed as one of five pervasive developmental disorders including autistic disorder, Retts disorder, childhood disintegrative disorder, Aspergers disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS). PDD-NOS is the diagnostic label typically reserved for children who show similar, severe social and communication deficits as in autism, or who demonstrate stereotypic behaviors and limited interests, but who may not have exhibited the behaviors by age three or who do not formally meet all criteria in all categories. Recent empirical findings suggest that many behavioral symptoms of autism can be detected within the first year of life, rather than in the third or fourth year. The Checklist for Autism in Toddlers (CHAT) is a popular tool among clinicians and researchers. It comprises fourteen different items that include elements of parental and clinical observation. The Childhood Autism Rating Scale (CARS) is a 15-item screening instrument designed to be completed by a trained observer or clinician.
