Autism Speaks is funding a three-year research project to assess the effect of proposed revisions to the criteria used to diagnose autism. These revisions concern the newest edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM-5).
The new study is among 22 Autism Speaks research grants announced last week. It builds on a recently funded project aimed at improving autism screening and estimates of prevalence. The aim of the study is to assess the impact of the DSM-5 criteria on the diagnosis and prevalence estimates of autism spectrum disorder (ASD).
Psychologist Laura Carpenter, Ph.D., of the Medical University of South Carolina, will lead the study with co-investigator Lydia King, Ph.D. It will be one of the first to compare the current DSM-IV criteria for autism to the proposed DSM-5 criteria during actual evaluation of children.
“Study after study is being published critiquing the DSM-5 criteria, but all of those studies are retrospective, using past records,” Dr. Carpenter explains. In other words, researchers applied the proposed new definition of ASD to case files of children previously diagnosed using DSM-IV criteria. They assessed whether the children would have kept their ASD diagnosis under the new criteria. However, old case files only record those symptoms that make up the DSM-IV criteria and often fail to note sensory behaviors and other symptoms included in the new DSM-5 checklist.
The new study will be conducted at one of the sites currently used by the Centers of Disease Control and Prevention (CDC) to estimate prevalence of ASD. This will provide important information regarding how the changes in diagnostic criteria might influence prevalence estimates. The study will include about 8,000 South Carolina schoolchildren born in 2004 and enrolled in the South Carolina Children’s Educational Surveillance Study (SUCCESS). The researchers will send an autism-screening questionnaire to their parents. From the responses, children identified as “at risk” will be invited to receive a full assessment. Dr. Carpenter’s team will use both the current DSM-IV criteria and the proposed DSM-5 criteria in their evaluations.
“The goal is to gain a better understanding of how the changes may impact certain groups of individuals,” Dr. Carpenter says. “It will give us good information about which kids will be more likely to be identified under the new criteria.”
If approved later this year, the new criteria will take effect when the DSM-5 publishes in May 2013. The South Carolina results will not be available before then. However, the DSM-5 criteria will be continually evaluated and modified. Thus, the results of this study can influence how the new criteria are used and may guide future DSM revisions.
“Autism Speaks represents hundreds of thousands of individuals and families affected by autism,” says Chief Science Officer Geri Dawson, Ph.D. “As such, we recognize the need for updating diagnostic criteria to reflect new scientific understanding. However, it’s crucial that we ensure that any revisions do not exclude individuals who have ASD and are in need of services. This is why we’re funding this important research.” (Also see Dr. Dawson’s related letters to the Autism Speaks community.)
This new study is an expansion of a research project that Autism Speaks funded last year. Likewise led by Drs. Carpenter and King, that project is investigating whether direct screening of schoolchildren improves identification of those with ASD. If so, such direct screening may increase the estimated prevalence of ASD in the United States (currently 1 in 88).
At present, the Centers for Disease Control and Prevention (CDC) estimates prevalence by reviewing physician and school records of children who have been evaluated for developmental difficulties. This method has allowed for prevalence estimates in very large populations. However, it’s not known how these results compare to studies that directly assess children, rather than relying on their records. A previous Autism Speaks funded study of direct screening found an unexpectedly high prevalence of 1 in 38 among South Korean schoolchildren.
“Our goal is to apply a population screening and assessment methodology and compare it to the CDC methodology to get the most accurate prevalence data,” says Dr. Carpenter. Both arms of the South Carolina project “are intimately related,” she adds. “The prevalence of ASD depends on how ASD is defined. If the definition changes, then prevalence is clearly going to be impacted in some way. I think it’s going to provide some really important information for helping understand autism prevalence.”
Over the last year, Autism Speaks has remained actively engaged in assessing the effects of the proposed DSM-5 changes, and continues to take a proactive role in ensuring that the revision will not exclude children or adults who need autism-related therapies and services. (See our full coverage of the proposed DSM-5 revisions here.)
To find out more about these and other studies funded by Autism Speaks, please explore our Grant Search. This research is made possible by the generosity and passion of Autism Speaks’ community of families, donors and volunteers.