title: Epidemiological surveys of autism and other pervasive developmental disorders: an update.
abstract: This paper was commissioned by the committee on the Effectiveness of Early Education in Autism of the National Research Council (NRC). It provides a review of epidemiological studies of pervasive developmental disorders (PDD) which updates a previously published article (The epidemiology of autism: a review. Psychological Medicine 1999; 29: 769-786). The design, sample characteristics of 32 surveys published between 1966 and 2001 are described. Recent surveys suggest that the rate for all forms of PDDs are around 30/10,000 but more recent surveys suggest that the estimate might be as high as 60/10,000. The rate for Asperger disorder is not well established, and a conservative figure is 2.5/10,000. Childhood disintegrative disorder is extremely rare with a pooled estimate across studies of 0.2/10,000. A detailed discussion of the possible interpretations of trends over time in prevalence rates is provided. There is evidence that changes in case definition and improved awareness explain much of the upward trend of rates in recent decades. However, available epidemiological surveys do not provide an adequate test of the hypothesis of a changing incidence of PDDs.
authors.affiliation: McGill University, Department of Psychiatry, The Montreal Children's Hospital, 4018 St. Catherine St. W., Montreal, QC H3Z 1P2, Canada. eric.fombonne@mcgill.ca
authors.forename: Eric
authors.initials: E
authors.lastname: Fombonne
mesh_terms: D000293:Adolescent; D001321:Autistic Disorder / Q000453:epidemiology*; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000453:epidemiology*; D002675:Child, Preschool; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D018479:Early Intervention, Educational / Q000706:statistics & numerical data; D005260:Female; D006301:Health Services Needs and Demand / Q000706:statistics & numerical data; D006306:Health Surveys; D006801:Humans; D007223:Infant; D008297:Male