The Rising Prevalence of Autism: A Prospective Longitudinal Study in the Faroe Islands

We have followed up a 2002 population study of autism prevalence in 15–24-year olds in the Faroe Islands. The rate of ASD grew significantly from 0.56% in 2002 to 0.94% in 2009. Although these results are within the range of typical findings from other studies, there were some interesting details. There were—in addition to 43 originally diagnosed cases in 2002—24 newly discovered cases in 2009 and nearly half of them were females. It is possible that unfamiliarity with the clinical presentation of autism in females have played a significant role in this context. There was diagnostic stability for the overall category of ASD over time in the group diagnosed in childhood (7—16) years, but considerable variability as regards diagnostic sub-groupings.