%0 Comparative Study
%T Autism With and Without Regression: A Two-Year Prospective Longitudinal Study in Two Population-Derived Swedish Cohorts.
%A Thompson L
%A Gillberg C
%A Landberg S
%A Kantzer AK
%A Miniscalco C
%A Barnevik Olsson M
%A Eriksson MA
%A Fernell E
%J J Autism Dev Disord
%V 49
%N 6
%D Jun 2019
%M 30734177
%F 4.345
%R 10.1007/s10803-018-03871-4
%X Two community-based cohorts of children with autism spectrum disorder, examined using similar assessment protocols, were pooled (n = 301) and subdivided according to history of regression. Those with regression (n = 62), 20.5% of the combined cohort, were contrasted with those without regression (n = 241) at first assessment (age range 19-60 months) and at 2-year follow-up on a range of measures. The regression group was significantly more functionally impaired, with regard to intellectual function (p < .001), language development (p < .001), and to severity of autism (p < .01) at both T1 and T2. Only 14 (23.3%) had a clearly identified underlying etiology [24 (18.6%) in the non-regressive group]. There were no significant differences between those who had regressed 'from normal' and those who had regressed 'from low' functioning.