Autism Fast Facts

(CNN)Here are some things to know about autism.

April 2 is World Autism Day.

From the Centers for Disease Control and Prevention:
Autism or autism spectrum disorder (ASD) incorporates 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.

From the American Psychiatric Association, Diagnostic and Statistical Manual (DSM-5)

"Autism spectrum disorder: The criteria will incorporate several diagnoses from DSM-IV including autistic disorder, Asperger's disorder, childhood disintegrative disorder, and pervasive developmental disorder (not otherwise specified), into the diagnosis of autism spectrum disorder for DSM-5 to help more accurately and consistently diagnose children with autism."

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."

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: One in 68 U.S. children has an autism spectrum disorder (ASD), a 30% increase from 1 in 88 in 2012, according to a 2014 report released by the Centers for Disease Control and Prevention.

    Cost:
    Medical costs for children with an ASD are six times higher than medical costs for children without an ASD. Caring for a child with autism ranges from an estimated $3.5 million to $5 million over a lifetime, according to the Autism Society.

    Vaccines and Autism:
    The American Academy of Pediatrics and the Institute of Medicine note that there is no scientifically proven link between the measles vaccination and autism. The World Health Organization (WHO) notes that the 1998 study that raised public concern was flawed and has been retracted.

    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."

    April 21, 2015 - A study of more than 95,000 children found no link between vaccines and autism. The study was funded by the National Institute of Mental Health, National Institutes of Health, and the U.S. Department of Health and Human Services.

    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.

    1980 - Autism is classified separately from schizophrenia in the third edition of the "Diagnostic and Statistical Manual of Mental Disorders."

    1994 - Asperger's syndrome is added to the fourth edition of the "Diagnostic and Statistical Manual of Mental Disorders" as a pervasive developmental disorder.

    2001 - Thimerosal, a mercury-based preservative, is reduced or removed from childhood vaccines after years of discussion about a relationship between it and autism.

    May 14, 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.

    December 18, 2007 - The United Nations adopts a resolution declaring April 2 World Autism Awareness Day.

    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."

    2013 - Autism spectrum disorder is the new name used in the fifth edition of the "Diagnostic and Statistical Manual of Mental Disorders" to encompass "autistic disorder (autism), Asperger's disorder, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified."

    March 27, 2014 - One in 68 U.S. children has an autism spectrum disorder (ASD), a 30% increase from 1 in 88 two years earlier, according to a new report released by the Centers for Disease Control and Prevention.

    October 29, 2014 - The medical journal Nature reports that scientists have identified 60 genes with a greater than 90% chance of increasing a child's autism risk. Previous research has yielded only 11 genes that had been confirmed with this level of certainty.

    Websites:
    American Academy of Pediatrics: What Parents Should Know About Measles-Mumps-Rubella (MMR) Vaccine and Autism
    American Psychiatric Association: DSM-5 Implementation and Support
    Autism Research Institute

    Autism Society of America
    Autism Speaks
    Centers for Disease Control and Prevention: Autism Spectrum Disorders (ASDs)
    Institute of Medicine of the National Academies: Immunization Safety Review: Vaccines and Autism