Prevalence of Autism in a US Metropolitan Area

Abstract

Individuals with autism have unusual social, communicative, and behavioral development and may have abnormalities in cognitive functioning, learning, attention, and sensory processing. Given the complex nature of autism and the spectrum of related disorders, current prevalence rates and whether rates have increased are highly debated topics.^1-5 Much of the descriptive epidemiology of autism comes from studies outside the United States (a summary of autism prevalence rates from epidemiologic studies is available from the authors). Autism prevalence rates from studies published before 1985 are 4 to 5 per 10 000 children for the broader autism spectrum and approximately 2 per 10 000 for the more narrowly defined condition termed classic autism.^6-12 Since 1985, non-US studies have reported higher rates of autism, ranging from a prevalence of 7 to 10 per 10 000 children for autistic disorder and an estimated prevalence for autism spectrum disorders 1.5 to 2.5 times higher.^7,13 A recent study conducted in the United Kingdom reported a prevalence rate of 16.8 per 10 000 children for autistic disorder and 62.6 per 10 000 for the entire autism spectrum.¹⁴