(HealthDay News)  — Use of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria is likely to lower prevalence estimates for autism spectrum disorders (ASDs), according to a study published online Jan. 22 in JAMA Psychiatry.

Matthew J. Maenner, PhD, from the University of Wisconsin-Madison, and colleagues conducted a cross-sectional, population-based ASD surveillance, based on clinician review of coded behaviors documented in children’s medical and educational evaluations. The study included 644,883 8-year-old children, living in 14 geographically defined areas in the United States participating in the Autism and Developmental Disabilities Monitoring (ADDM) Network in 2006 or 2008, of whom 6,577 met surveillance ASD case status based on the DSM-IV-TR.

The researchers found that 81.2 percent of those classified by the ADDM Network as having ASD according to the DSM-IV-TR criteria met the ASD DSM-5 criteria. The percentage was similar for boys and girls, and was significantly higher for those with (86.6%) vs. those without (72.5%) intellectual disability (P<0.001). Three hundred four children met DSM-5 criteria for ASD but not current ADDM Network ASD case status. Using DSM-5 criteria, the prevalence of ASD would have been 10.0 per 1,000 in 2008, compared with the reported prevalence of 11.3 based on DSM-IV-TR criteria.

“Autism spectrum disorder prevalence estimates will likely be lower under DSM-5 than under DSM-IV-TR diagnostic criteria, although this effect could be tempered by future adaptation of diagnostic practices and documentation of behaviors to fit the new criteria,” the authors write.

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