Diagnostic Terminology

The terminology, the words or terms we use to diagnose Autism Spectrum Disorder (ASD), is constantly changing. As assessment tools are developed, the set of described behaviours are defined in new ways. There have been many changes made to the diagnostic terminology over time, and while it is important to know the history, what is most important is meeting the needs of autistic people and their families.

In Canada and the United States, the Diagnostic and Statistical Manual of Mental Disorders (DSM) is widely used by clinicians and psychiatrists for the classification of mental disorders. In 2013, the American Psychiatric Association published the fifth edition of this manual (DSM–5). Whereas under the previous editions of the manual, patients could be diagnosed with Autistic Disorder, Asperger’s Disorder, Childhood Disintegrative Disorder, or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), DSM-5 now encompasses all four diagnoses under the umbrella of Autism Spectrum Disorder. Additionally, DSM-5 now groups communication and social interaction under a single domain.

Despite the changes to the diagnostic terminology, anyone who previously received a diagnosis of Autistic Disorder, Asperger’s Disorder, Childhood Disintegrative Disorder, or Pervasive Developmental Disorder Not Otherwise Specified should still meet the criteria for ASD in DSM-5.

Chart showing the difference between categories in the DSM 4 and DSM 5

Severity ratings are based on level of support required.

For more information about changes to the DSM-5 or the diagnostic criteria, please contact your local Region or your local Service Navigator.