The fifth edition of the diagnostic and statistical manual of mental disorders (DSM-5) (APA in diagnostic and statistical manual of mental disorders, Author, Washington, 2013) has decided to merge the subtypes of pervasive developmental disorders into a single category of autism spectrum disorder (ASD) on the assumption that they cannot be…

The classification of autism spectrum disorders (ASDs) is a topic of debate among clinicians and researchers with many questioning the validity of the distinction among subtypes. This manuscript examines the validity of three ASD subtypes (Autism, Asperger's, and PDDNOS) by reviewing 22 studies published between 1994 and 2006. We reviewed studies…

This paper reviews 20 studies that investigated the internal or external validity of various subtypes of autistic spectrum disorders. At least three groups could be distinguished from autism on clinical grounds: an Asperger syndrome subtype, and two atypical subtypes characterized by either low intelligence quotient or high intelligence quotient.…

This review summarizes subject selection and diagnostic procedures documented in 142 empirical articles published between 1993 and 1997. Although most researchers reported use of standard diagnostic criteria in classifying subjects, numerous studies did not report diagnostic methods and there was often a lack of specification of inclusion and…

This review of studies of early onset schizophrenia examines the nosological similarity between adult and early onset schizophrenia, differential diagnosis, treatment, and the extent to which children and adolescents diagnosed as having schizophrenia using adult criteria have the characteristic adult correlates. The paper discusses gender…

The reliability, validity, and clinical utility of the Asperger Syndrome Diagnostic Scale in the diagnosis of pervasive developmental disorders are reviewed. While the measure holds promise as a research tool, there appears little evidence that it can distinguish among the variety of types of pervasive developmental disorders, or diagnose Asperger…