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Objective: 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. Results: 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. Conclusions: The rate of pervasive developmental disorders is higher than reported 15 years ago. The rate in this study is comparable to that in previous birth cohorts from the same area and surveyed with the same methods, suggesting a stable incidence.

Objective: Neurodevelopmental impairments have been associated with early-onset schizophrenia, early-onset bipolar disorder, and childhood-onset affective disorder. The authors investigated whether delayed childhood motor skills predicted persistent anxiety in adolescence among 6,850 subjects from a national 1958 U.K. birth cohort. Method: This historic cohort study used data from the National Child Development Study that was collected when its subjects were 7, 11, and 16 years old. Results: Boys with poor motor skills had more than threefold the odds of maternally rated anxiety at the ages of 11 and 16, but no effect was observed for girls. Conclusions: Childhood motor impairment was strongly associated with persistent anxiety among male, but not among female, adolescents. The effect modification by sex was greater than expected, as was the effect size for boys. Both findings warrant replication and further examination.

Objective: This project focused on the development of the definition of autism for DSM-IV. Method: Multiple sites were involved in obtaining information regarding 977 patients with the following clinician-assigned diagnoses: autism (N = 454), other pervasive developmental disorders (N = 240), and other disorders (N = 283). A standard coding system was used, and the raters (N = 125) had a range of experience in the diagnosis of autism. Patterns of agreement among existing diagnostic systems were examined, as was the rationale for inclusion of other disorders within the class of pervasive developmental disorders. Results: The DSM-III-R definition of autism was found to be overly broad. The proposed ICD-10 definition most closely approximated the clinicians' diagnoses. Inclusion of other disorders within pervasive developmental disorders appeared justified. Partly on the basis of these data, modifications in the ICD-10 definition were made; this and the DSM-IV definition are conceptually identical. Conclusions: The resulting convergence of the DSM-IV and ICD-10 systems should facilitate both research and clinical service.