Here are some fast facts about autism.
April 2 is World Autism Day.
From the Centers for Disease Control and Prevention: Autism or autism spectrum disorders (ASDs) are a group of neurodevelopmental disorders, causing impaired communication skills and social skills. ASDs generally start before three years of age and last a lifetime, but early intervention plays a role in treatment and progress.
Types: From the American Psychiatric Association, Diagnostic and Statistical Manual (DSM V) There are several types of ASDs: Autistic Disorder, Asperger Disorder, Childhood Disintegrative Disorder, and Pervasive Developmental Disorder.
Possible characteristics: According to the American Academy of Pediatrics, "The main characteristics of autism are difficulties in social interaction, communication, and restrictive and repetitive interests and activities."
The National Autism Association on the "Signs of Autism."
Boys are five times more likely than girls to have ASDs.
ASDs can be found amongst all races, ethnicities, and socioeconomic groups.
Estimates: The CDC on "Determining How Many People Have ASDs."
World: Tens of millions worldwide are affected with ASD (Autism Speaks)
United States: 1 in 88 (11.3 per 1,000) children have autism, according to CDC estimates, but 1 in 50 school-aged children have autism, according to a CDC survey of parents.
Cost: Medical costs for children with an ASD are six times higher than medical costs for children without an ASD.
Possible connection to vaccines: The American Academy of Pediatrics and the Institute of Medicine note that there is no scientifically proven link between measles vaccination and autism, although the National Autism Association reports that it is caused by environmental factors.
2004 - The Institute of Medicine (IOM) of the National Academies examines the possibilities of an association between vaccines and autism in its immunization safety review and finds no causal relationship.
2012 - The IOM reconfirms its findings of a lack of causal relationship between vaccines and autism in the publication: "Adverse Effects of Vaccines: Evidence and Causality."
Timeline: Early 1900s - Autistic characteristics are studied as symptoms of schizophrenia.
October 1938 - Five-year-old Donald Gray Triplett of Mississippi is first examined by child psychiatrist Leo Kanner of Johns Hopkins Hospital and later becomes the first person diagnosed with autism symptoms.
1943 - Triplett is referred to as "Donald T." in the paper "Autistic Disturbances of Affective Contact," by Leo Kanner. The paper expounds on the idea that autism is related to lack of parental warmth; this is later dubbed the "refrigerator mother" theory.
1944 - Hans Asperger, an Austrian physician, publishes a paper about autistic syndrome. The paper gains wider recognition when it is translated into English in the early 1990s.
1964 - Bernard Rimland, a research psychologist, publishes "Infantile Autism: The Syndrome and Its Implications for a Neural Theory of Behavior," which contradicts the "refrigerator mother" hypothesis. The author of the foreword is child psychiatrist Leo Kanner.
1965 - Rimland founds the National Society for Autistic Children (now the Autism Society of America) which rejects the "refrigerator mother" theory.
1967 - Autism is classified as a syndrome of schizophrenia in the "International Statistical Classification of Diseases and Related Health Problems."
1967 - University of Chicago professor Bruno Bettelheim writes "The Empty Fortress: Infantile Autism and the Birth of the Self" in which he notes that parents are to blame for the autistic characteristics of their children. The term "refrigerator mother" is popularized again.
1967 - Bernard Rimland establishes the Autism Research Institute.
1969 - Leo Kanner, speaking at a meeting of the Autism Society of America, says he was misquoted in attributing the cause of autism exclusively to parents.