Neural network technology was compared with simultaneous and stepwise linear discriminant analysis in terms of their ability to classify and predict persons (n=138) as having autism or mental retardation. The neural network methodology was superior in both classifying groups and in generalizing to new cases that were not part of the training…

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 paper reviews whether Rett syndrome is a subtype of pervasive developmental disorders (PDD). The paper analyzes internal and external diagnostic validity and discusses whether Rett syndrome is a neurological disorder or a mental disorder. The paper concludes that data support the idea of classifying Rett syndrome as a subtype of PDD.…

This paper presents evidence regarding the validity of the diagnostic concept of "autistic-like" childhood disintegrative disorder, also known as Heller syndrome or as disintegrative psychosis. Its inclusion in the DSM-IV (Diagnostic and Statistical Manual) is supported, and proposed criteria and narrative description are provided.…

This study compared DSM-III-R (Diagnostic and Statistical Manual III, Revised), Childhood Autism Rating Scale, and clinical diagnoses of 138 admissions to a program for diagnosis and treatment of autistic and related communication-handicapped individuals. Results indicated generally high agreement on the diagnosis of autism, with DSM-III-R…

This paper assesses to what extent the ICD-10 (International Classification of Diseases) criteria differ from other diagnostic systems for Asperger syndrome. The paper concludes that the variety of criteria in use makes interpretation of research findings difficult and that the ICD-10 criteria are the most stringent and closest to Hans Asperger's…

This paper compared clinicians' diagnosis and DSM-III (Diagnostic and Statistical Manual), DSM-III-R (Revised), and ICD-10 (International Classification of Diseases) diagnoses of 52 individuals with autism and 62 nonautistic, developmentally disordered individuals. The DSM-III-R system overdiagnosed the presence of autism, and ICD-10 closely…

This essay notes the complexities inherent in classifying pervasive developmental disorders (PDD), especially when a single classification scheme is to be used for clinical, research, and administrative purposes. The paper considers principles of classification, symptomatology, the neuropsychiatric interface, the value of a multiaxial approach,…

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…

Forty parents of children with autism or pervasive developmental disorder completed the Wing Subgroups Questionnaire, developed for subclassifying children into one of L. Wing's three hypothesized subgroups. Results indicated that the questionnaire has adequate external criterion-referenced validity, with similar subgroup ratings made by…

Autism Behavior Checklists were completed for 52 autistic individuals (ages 2-31) and 62 nonautistic individuals, and data were analyzed using signal detection methodology. A single item (looks "through" people) combined with one of five other items discriminated as well as the sum scores, and further combinations did not improve…

The Autism Behavior Checklist was completed for 67 autistic and 56 mentally retarded and learning-disabled children (ages 6-15). The checklist was effective in classifying children when using either the full scale or only the more highly weighted items. Results did not support a single unidimensional scale or subdividing the checklist into five…