The classification of autism, Asperger's syndrome, and pervasive developmental disorder

The current classification of the pervasive developmental disorders (PDDs) as conceptualized in both the DSM-IV and ICD-10 is deeply unsatisfying to many parents, front-line clinicians, and academic researchers. Is the diagnostic validity of the various disorders simply lacking empirical data for full substantiation, or does the overall conceptualization of the category have more fundamental problems, not reflecting the "true" nature of the phenomena? This paper argues the latter hypothesis. I review the historical development of the classification of PDD, summarize recent empirical data on issues of reliability and validity, and suggest a new approach to classification and understanding.