Article

Epidemiology of Pervasive Developmental Disorders

Department of Psychiatry, Montreal Children's Hospital of the McGill University Health Centre, Montreal, Quebec, Canada.
Pediatric Research (Impact Factor: 2.31). 03/2009; 65(6):591-8. DOI: 10.1203/PDR.0b013e31819e7203
Source: PubMed

ABSTRACT

This article reviews the results of 43 studies published since 1966 that provided estimates for the prevalence of pervasive developmental disorders (PDDs), including autistic disorder, Asperger disorder, PDD not otherwise specified, and childhood disintegrative disorder. The prevalence of autistic disorder has increased in recent surveys and current estimates of prevalence are around 20/10,000, whereas the prevalence for PDD not otherwise specified is around 30/10,000 in recent surveys. Prevalence of Asperger disorder is much lower than that for autistic disorder and childhood disintegrative disorder is a very rare disorder with a prevalence of about 2/100,000. Combined all together, recent studies that have examined the whole spectrum of PDDs have consistently provided estimates in the 60-70/10,000 range, making PDD one of the most frequent childhood neurodevelopmental disorders. The meaning of the increase in prevalence in recent decades is reviewed. There is evidence that the broadening of the concept, the expansion of diagnostic criteria, the development of services, and improved awareness of the condition have played a major role in explaining this increase, although it cannot be ruled out that other factors might have also contributed to that trend.

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Available from: Eric Fombonne, Apr 01, 2015
    • "On the other hand, in a sample of 75 children with ASD drawn from the Special Needs and Autism Project (SNAP) cohort, Charman et al. (2011) reported a slightly higher prevalence of ID in ASD (55%) (Charman et al., 2011). Moreover, findings related to the occurrence of ID in autism consistently report that females with ASD have lower average cognitive ability than males, and the male to female ratio in ASD is highest when ID is not present (Fombonne, 2009; Nicholas et al., 2008; Bryson, Bradley, Thompson, & Wainwright, 2008). Finally, studies on the prevalence rates of comorbid ID in ASD in Italy are still lacking. "

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    • "ASD is a common condition with recent epidemiological studies in the United Kingdom Autism estimating prevalence at between 1% (Brugha et al., 2012) and 1.7% (Russell et al., 2014). Males are diagnosed approximately four times more often than females in childhood (Fombonne, 2005Fombonne, , 2009) although this ratio varies with IQ and is reportedly as low as 2:1 when ASD is comorbid with intellectual disability, and as high as 6–8:1 in high-functioning populations (Fombonne, 2005 ). The reason for the gender discrepancy is unclear. "
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