Autism spectrum disorders according to DSM-IV-TR and comparison with DSM-5 draft criteria: an epidemiological study

The latest definitions of autism spectrum disorders (ASDs) were specified in DSM-IV-TR in 2000. DSM-5 criteria are planned for 2013. Here, we estimated the prevalence of ASDs and autism according to DSM-IV-TR, clarified confusion concerning diagnostic criteria, and evaluated DSM-5 draft criteria for ASD posted by the American Psychiatry Association (APA) in February 2010.

This was an epidemiological study of 5,484 eight-year-old children in Finland, 4,422 (81%) of them rated via the Autism Spectrum Screening Questionnaire by parents and/or teachers, and 110 examined by using a structured interview, semi-structured observation, IQ measurement, school-day observation, and patient records. Diagnoses were assigned according to DSM-IV-TR criteria and DSM-5 draft criteria in children with a full-scale IQ (FSIQ) ≥50. Patient records were evaluated in children with an FSIQ <50 to discover diagnoses of ASDs.

The prevalence of ASDs was 8.4 in 1,000 and that of autism 4.1 in 1,000 according to DSM-IV-TR. Of the subjects with ASDs and autism, 65% and 61% were high-functioning (FSIQ ≥70), respectively. The prevalence of pervasive developmental disorder not otherwise specified was not estimated because of inconsistency in DSM-IV-TR criteria. DSM-5 draft criteria were shown to be less sensitive in regard to identification of subjects with ASDs, particularly those with Asperger's syndrome and some high-functioning subjects with autism.

DSM-IV-TR helps with the definition of ASDs only up to a point. We suggest modifications to five details of DSM-5 draft criteria posted by the APA in February 2010. Completing revision of DSM criteria for ASDs is a challenging task.