Pervasive Developmental Disorders in Preschool Children: Confirmation of High Prevalence

The rate of reported pervasive developmental disorders has increased, and the authors found a rate of 62.6 per 10,000 in a previous study of preschoolers in Stafford, U.K. They conducted another survey in 2002 to estimate the prevalence in children in a later birth cohort and to compare it to previous findings from the same area. METHOD: Screening for developmental problems included 10,903 children ages 4.0 to 6.0 years who were living in a Midlands town on the survey date. Children with symptoms suggestive of pervasive developmental disorders were intensively assessed by a multidisciplinary team using standardized diagnostic interviews, psychometric tests, and medical workups.

Sixty-four children (85.9% boys) were diagnosed with pervasive developmental disorders. The prevalence was 58.7 per 10,000, with a 95% confidence interval (CI) of 45.2-74.9, for all pervasive developmental disorders, 22.0 per 10,000 (95% CI=14.1-32.7) for autistic disorder, and 36.7 per 10,000 (95% CI=26.2-49.9) for other variants. These rates were not significantly different from the previous rates. The mean age at diagnosis was 37.8 months, and 53.1% of the children were originally referred by health visitors. Of the 64 children with pervasive developmental disorders, 29.8% had mental retardation, but this rate varied by disorder subtype. Few children had associated medical conditions.