Time Trends in Diagnostics and Clinical Features of Young Children Referred on Suspicion of Autism: A Population-Based Clinical Cohort Study, 2000-2010.

The present study aimed to explore clinical trends in the period 2000-2010, along with discriminating clinical factors for autism spectrum disorder (ASD), in young children suspected of ASD. The following trends were observed: (1) a rise in referrals including an increase in referrals among language-abled children, (2) an increase in children assigned an ASD diagnosis after assessment, and (3) a decrease in Autism Diagnostic Observation Schedule total score. The distribution of ASD subtypes and IQ level did not change. Results suggest that a higher proportion of children with less severe autism symptoms were referred and diagnosed. Further, restricted and repetitive behaviors seemed to be a key discriminating factor when distinguishing between ASD and no-ASD children with a discordant symptom profile.