Stringent DSM-5 criteria may affect prevalence rates of autism spectrum disorders



Despite similarities in behavior, some children diagnosed with autism spectrum disorders under the DSM-IV-TR could lose their diagnosis as a result of the new manual’s stricter diagnostic criteria.

A recent study shows that 46.7% of toddlers diagnosed with autism spectrum disorders (ASDs) under the DSM-IV-TR (the previous version of the diagnosis manual) will no longer meet autism spectrum criteria under the DSM-5. The new version of the go-to psychiatric manual imposes a rigorous set of criteria for diagnosis, requiring more total symptoms to be met in the areas of social/communication deficits and repetitive/restrictive behaviors than did the DSM-IV-TR.

"The definition of autism has evolved over the years, with previous modifications of the DSM criteria resulting in marked effects on prevalence rates," wrote study author Lindsey W. Williams of Louisiana State University, Baton Rouge. This change is important to note, she said, because DSM-based diagnoses are "widely used by insurance and service providers to qualify individuals for services."

Autism spectrum disorders are characterized by three general defining factors: social skills deficits, communication impairments, and repetitive/restricted behaviors. Services used to treat autism may include early intensive behavioral intervention (EIBI), speech therapy, physical therapy, and occupational therapy.

This study evaluated challenging behaviors in 3,339 toddlers aged 17 months to 37 months. Children were divided into three groups: DSM-5, DSM-IV-TR only, and atypically developing/non-ASD. The DSM-5 toddlers met DSM-IV-TR criteria for autism, and maintained this diagnosis under the new DSM-5 requirements. The second group did not meet the new criteria but did meet ASD criteria under the DSM-IV-TR. The last group consisted of children who did not meet ASD criteria under either version of the DSM but did have some symptoms of atypical or delayed development.

Investigators made diagnoses using a series of evaluation tools for autism, including the DSM-5; DSM-IV-TR; Modified Checklist for Autism in Toddlers (M-CHAT); Battelle developmental inventory, second edition (BDI-2); and the Baby and Infant Screen for Children with aUtism Traits (BISCUIT). "Challenging behavior types" were categorized as aggressive/destructive behaviors, stereotyped behaviors, and self-injurious behaviors.

The study found that the three groups did not significantly differ based on sex or race. The results, in accordance with prior research, show that 46.7% of children diagnosed on the autism spectrum under DSM-IV-TR criteria will no longer meet the requirements for ASD under the DSM-5.

Significant differences were found among all groups with regard to challenging behaviors, with a large effect size found between the atypically developing (non-ASD) and severe ASD DSM-5 groups. In a comparison of the DSM-IV-TR and DSM-5 groups, medium effect sizes were found for aggressive destructive behaviors and self-injurious behaviors, and large effect sizes were found for stereotyped and total problem behaviors. A comparison of the DSM-IV-TR group with the atypically developing group found medium effect sizes across all behavior types.

Children with the most severe symptoms and challenging behaviors probably will be able to retain their ASD diagnosis under the DSM-5, but the investigators expressed concern about the decreased sensitivity of the new requirements, stating that "individuals who no longer qualify for an ASD diagnosis ... will nonetheless continue to have significant behavioral issues warranting behavioral intervention," especially because the DSM-IV-TR group more closely resembled the DSM-5 group in this study.

It is unclear how the new diagnostic criteria will affect access to therapies for children who no longer meet ASD criteria, but they said that "it is imperative that a loss of ASD diagnosis does not disqualify individuals from receiving important behavioral interventions," wrote Ms. Williams, a doctoral student in the clinical psychology program at the university.

The investigators had no financial disclosures to report.

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