Differences across counties in the registered prevalence of autism, ADHD, epilepsy and cerebral palsy in Norway.

BACKGROUND In 2012, we published an overview of the prevalence of developmental disorders and neurological diseases in children in Norway, which was unknown at the time. In this article we will compare diagnostics and treatment across counties and institutions. MATERIAL AND METHOD The prevalence across counties of autism spectrum disorders, ADHD, epilepsy and cerebral palsy in children aged 0-12 was estimated with the aid of data from the Norwegian Patient Register for the years 2008-11. RESULTS In the age group 6-12 years, nationwide prevalence amounted to 0.6% for autism spectrum disorders, 2.0% for ADHD, 0.9% for epilepsy and 0.3% for cerebral palsy. In total, 5.0% of all twelve-year-olds were registered with one or more of these diagnoses. The prevalence of autism spectrum disorders and ADHD varied between the counties, from 0.3% to 1.5% for autism spectrum disorders and from 1.1% to 3.5% for ADHD. For epilepsy and cerebral palsy there was little variation between the counties. Diagnostics and treatment of these four conditions are spread over 29 somatic hospitals and 102 units for child and youth psychiatry. INTERPRETATION The variations across counties in the prevalence of autism spectrum disorders and ADHD are most likely due to variations in diagnostic practices. We ask whether it is appropriate to spread the provision of treatment across such a high number of institutions.