Autism

Autism, also called classic autism or autistic disorder, developmental disorder affecting physical, social, and language skills, with an onset of signs and symptoms typically before age three. The term autism (from the Greek autos, meaning “self”) was coined in 1911 by Swiss psychiatrist Eugen Bleuler, who used it to describe withdrawal into one’s inner world, a phenomenon he observed in individuals with schizophrenia. The use of the word autism to describe the condition as it is known today originated in 1943, when Austrian-born American psychiatrist Leo Kanner distinguished the disorder from schizophrenia.

Classic autism, Asperger syndrome, and pervasive developmental disorder not otherwise specified (PDD-NOS) are all included within an umbrella of disorders commonly referred to as autism spectrum disorders (ASDs). In contrast to classic autism, individuals with Asperger syndrome usually do not possess major cognitive difficulties, and their IQ is in the normal or even high range. In addition, they do not exhibit a delay in language acquisition. Individuals with PDD-NOS exhibit some but not all of the same signs and symptoms as classic autism.

The U.S. Centers for Disease Control (CDC) estimated that ASDs affect a range roughly between 1 in every 45 and 1 in every 68 children in the United States. In the United Kingdom a school-based population study published in 2009 estimated prevalence at about 1 in every 100 children. In both countries, males are affected four to five times more often than females.

While best estimates have been determined, the incidence of autism varies significantly between and within countries, which is partly due to differences in resources and the clinical definitions used for diagnosis. For example, in one region of the United Kingdom, roughly 1 in every 185 individuals was found to be affected by an ASD. However, in the same region of the country, classic autism was found to range in incidence between 1 in 250 and 1 in 400 individuals. In addition, there appears to have been a dramatic increase in the global incidence of autism between the mid-1900s and the early 2000s. However, it is not known whether there has been a true increase in the incidence of the disorder, since the increase could be due to the use of broader diagnostic criteria or other factors. In the United States, for example, the National Health Interview Survey (NHIS) is one of several different surveillance methods used to determine ASD prevalence. In 2014 changes in NHIS questions about ASD, including rewording and expansion for greater detail, were associated with a subsequent increase in parent-reported diagnoses of ASDs in children.