Autism With and Without Regression: A Two-Year Prospective Longitudinal Study in Two Population-Derived Swedish Cohorts

J Autism Dev Disord. 2019 Jun;49(6):2281-2290. doi: 10.1007/s10803-018-03871-4.


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.

Keywords: ASD; Autism; Developmental language disorder; Intellectual developmental disorder; Non-regressive autism; Regressive autism.

Publication types

  • Comparative Study

MeSH terms

  • Autism Spectrum Disorder / diagnosis
  • Autism Spectrum Disorder / epidemiology*
  • Autism Spectrum Disorder / psychology*
  • Child
  • Child, Preschool
  • Cohort Studies
  • Female
  • Follow-Up Studies
  • Humans
  • Language Development*
  • Longitudinal Studies
  • Male
  • Population Surveillance* / methods
  • Prospective Studies
  • Regression, Psychology*
  • Sweden / epidemiology