Early diagnosis of children with autism spectrum disorders

Research focusing on early development in children with Autism Spectrum Disorders (ASD) has been of particular interest in recent years. A greater understanding of the accuracy of early diagnosis, as well as the developmental pathways that are observed in young children with ASD, is of both theoretical and practical importance. In accordance with these concerns, this review addresses questions about three topics: the reliability of early diagnosis, the validity of using narrow versus broad diagnostic categories, and trajectories of development in children with ASD. Findings from two prospective longitudinal studies are reviewed. The first investigation included children referred for ASD at age 2 who were followed for one year. The second study followed children referred for ASD at age 2 until age 9. Results suggested that early diagnoses can be made reliably, that there is no empirical evidence for using narrowly defined diagnostic categories within ASD and that trajectories of development showed considerable heterogeneity. (C) 2006 Association for Research in Nervous and Mental Disease. Published by Elsevier B.V. All rights reserved.