Author Interviews, Autism, JAMA / 03.11.2014
Rise In Autism Rates Largely Due to Changes in Diagnostic Criteria
MedicalResearch.com Interview with:
Stefan Nygaard Hansen PhD Student, MSc Stat
Section for Biostatistics
Department of Public Health
Aarhus University Denmark
Medical Research: What are the main findings of the study?
Response: The main finding of our study is that 60% of the observed increase in autism prevalence among children born 1980-1991 in Denmark can be explained by changes in the way diagnoses are established and changes in the subsequent registration to national health registries.
In 1994, the diagnostic criteria used by clinicians to establish psychiatric diagnoses was changed. This meant the recognition of autism as a spectrum of disorders but it also meant changes in the specific symptoms that form the basis of the autism diagnosis. In 1995, the national health registries in Denmark, which are often used in Danish health research, began to also include diagnoses given in connection with outpatient consultations whereas before 1995 only diagnoses given in connection with hospitalization was reported to the registries. This could mean that we after 1995 see more of the mild autism diagnoses since they may not require hospitalization.
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