The five historical and theoretical events are:

• Pioneer views of ASD prior to 1900s
• Clinicians and researchers associated autism spectrum disorder with "refrigerator mothers" and childhood schizophrenia
• The standardization of diagnostic criteria for ASD, including a discussion of Ivar Lovaas' intensive behavior therapy results
• The study published by Andrew Wakefield in 1998 suggesting that the measles-mumps-rubella (MMR) vaccine causes autism
• Revision of the DSM-5