The terminology of autism has changed a great deal over the past 100 years as researchers gained knowledge about the condition. The current diagnostic criteria, in place since the fifth edition of the Diagnosis and Statistical Manual of Mental Disorders (DSM-5) was published in 2013, reclassifies all previously distinct autism-related diagnoses under one umbrella, that of autism spectrum disorder (ASD). The word spectrum describes the wide variety of behaviors and other symptoms at differing severity levels in people with autism. ASD describes symptoms in two areas:

• Persistent deficits in social communication and social interaction
• Restricted, repetitive patterns of behavior, interests, or activities

The criteria also provide a basis for rating the severity of symptoms in both areas as 1 (requiring support), 2 (requiring substantial support), or 3 (requiring very substantial support).

Social (pragmatic) communication disorder (SCD) is a newer, separate diagnosis added in the DSM-5. SCD describes difficulties in social interaction, verbal and nonverbal communication, understanding of social situations, and pragmatics (language as used within different contexts). ASD must be ruled out before SCD can be diagnosed – no one would be diagnosed with both. Some people originally diagnosed in previous years with autism or another related condition might be diagnosed with SCD if tested again under the new criteria.

Older Classifications and Diagnoses

Autism spectrum disorder includes several conditions that were considered distinct diagnoses until 2013. The following classifications are no longer used:

• Asperger syndrome
• Pervasive developmental disorder not otherwise specified (PDD-NOS)
• Autistic disorder
• Childhood disintegrative syndrome
• Rett’s disorder

Timeline of Autism Classification

• 1908 – The word “autism,” from the Greek autos, meaning self, was first used by Swiss psychiatrist Eugen Bleuler to describe schizophrenic patients who were especially withdrawn into themselves.
• 1952 – In the DSM-I, autism is categorized under childhood schizophrenia. This classification was retained in the DSM-II, published in 1968.
• 1980 – “Infantile autism” was listed separately from childhood schizophrenia in the DSM-III.
• 1987 – “Autism disorder” replaced “infantile autism” in the DSM-III-R, a revised edition of the DSM-III.
• 1994 – Asperger syndrome, autistic disorder, childhood disintegrative syndrome, Rett's disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS) were listed under the umbrella term “pervasive development disorders” in the DSM-IV.
• 2013 – Autism spectrum disorder was added to the DSM-5 as an umbrella condition encompassing all previous separate autism-related diagnoses. Social (pragmatic) communication disorder (SCD) is introduced as a distinct diagnosis.

Condition Guide

• Autism – An Overview
• Autism – The Path to Diagnosis
• Behaviors and Other Symptoms of Autism
• Treatments for Autism