Recent worldwide epidemiological surveys of autism conducted in 37 countries are reviewed; the median prevalence of autism is 0.97% in 26 high-income countries. Methodological advances and remaining challenges in designing and executing surveys are discussed, including the effects on prevalence of variable case definitions and nosography, of…

Our study examines the Diagnostic and Statistical Manual--Fifth Edition (DSM-5) and Diagnostic and Statistical Manual--Fourth Edition, Text Revision (DSM-IV-TR) when applied concurrently against the best estimate clinical diagnoses for 110 children (5.1-19.6 years old) referred for diagnostic assessments of Autism Spectrum Disorder (ASD) in a…

A number of changes were made to pervasive developmental disorders (PDDs) in the recently released diagnostic and statistical manual of mental disorders (APA, "Diagnostic and statistical manual of mental disorders," American Psychiatric Publishing, Arlington, VA, 2013). Of the 210 participants in the present study who met DSM-IV-TR…

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…

To identify factors associated with valid Autism Spectrum Disorder (ASD) diagnoses from electronic sources in large healthcare systems. We examined 1,272 charts from ASD diagnosed youth <18 years old. Expert reviewers classified diagnoses as confirmed, probable, possible, ruled out, or not enough information. A total of 845 were classified with…

There is a need for brief screening instruments for autistic spectrum disorders (ASD) that can be used by frontline healthcare professionals to aid in the decision as to whether an individual should be referred for a full diagnostic assessment. In this study we evaluated the ability of a short form of the autism spectrum quotient (AQ)…

This study examined changes in the administrative prevalence of autism spectrum disorders (ASD) in Utah children from 2002 to 2008 by record source (school and health), age (four, six, and eight), and special education classification. Prevalence increased 100% with 1 in 77 children aged eight identified with ASD by 2008. Across study years and age…

Three levels of investigation underlie all biologically based attempts at classification of behaviorally defined developmental and psychiatric disorders: Level A, pseudo-categorical classification of mostly dimensional descriptions of behaviors and their disorders included in the 2013 American Psychiatric Association's Fifth Edition of the…

The purpose of this study was to assess the validity of the diagnosis of childhood autism in the Danish Psychiatric Central Register (DPCR) by reviewing medical records from 499 of 504 total children with childhood autism born 1990-1999. Based on review of abstracted behaviors recorded in case records from child psychiatric hospitals, case status…

To test the effects of providing relational cues at encoding and/or retrieval on multi-trial, multi-list free recall in adults with high-functioning autism spectrum disorder (ASD), 16 adults with ASD and 16 matched typical adults learned a first followed by a second categorised list of 24 words. Category labels were provided at encoding,…

The current study used a factorial comparison experimental design to investigate conflicting findings on prototype effects shown by children with autism (Klinger and Dawson, "Dev Psychopathol" 13:111-124, 2001; Molesworth et al., "J Child Psychol Psychiatry" 46:661-672, 2005). The aim was to see whether children with high-functioning autism could…

The revised ADOS algorithms, proposed by Gotham et al. (J Autism Dev Disord 37:613-627, 2007), were investigated in an independent sample of 558 Dutch children (modules 1, 2 and 3). The revised algorithms lead to better balanced sensitivity and specificity for modules 2 and 3, without losing efficiency of the classification. Including the…

Fourteen children with autism spectrum disorders (ASD) and fourteen age-matched typically-developing (TD) controls were tested on an adapted version of the Twenty Questions Task (Mosher and Hornsby in Studies in cognitive growth. Wiley, New York, pp 86-102, "1966") to examine effects of content, executive and verbal IQ factors on category use in…

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…

There has been little evidence to support the hypothesis that diagnostic substitution may contribute to increases in the administrative prevalence of autism. We examined trends in assignment of special education codes to British Columbia (BC) school children who had an autism code in at least 1 year between 1996 and 2004, inclusive. The proportion…