Epidemiology of Autism Spectrum Disorders

Abstract

AbstractEpidemiological surveys of autism spectrum disorders (ASDs) have been performed since the mid‐1960s. Methodological differences make between‐survey comparisons difficult to perform, thus making it difficult to evaluate actual prevalence of ASDs over time. Surveys from the 1990s show an increase in ASD diagnosis in most countries. Evidence suggests this rise does not indicate an actual increase in incidence (an epidemic). Instead, the upward trend is probably related to changes in concepts, definitions, services availability, and awareness of ASDs among general population and professionals. Correlates that can affect the accuracy of these survey figures include socioeconomic status, race/ethnicity, and immigrant status.