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