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How Has the Definition and Diagnosis of Autism Changed Over Time?


Updated July 22, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

What Is the DSM?

The DSM (Diagnostic and Statistical Manual of Mental Disorders), is developed and updated on a regular basis by the American Psychiatric Association. The book is often called the “Bible” of mental health diagnoses, but this is a bit of a misnomer. Unlike the Bible, the DSM is not believed by anyone, including its writers, to be a reflection of unchanging truth. Instead, it is an ever-changing collection of diagnostic criteria for an ever-changing collection of diagnoses, written by a group of psychiatrists most of whom are Americans, and all of whom are the products of their own time and place.

At one time, homosexuality was included in the DSM as a psychiatric disorder; today it is gone, but “Caffeine Use Disorder” is a brand new diagnosis along with “hoarding,” and several other never-before-defined disorders. I say this to place the DSM-5 diagnostic criteria for the newly minted “Autism Spectrum Disorder” in context: it’s important to know that the DSM is (1) not a reflection of immutable medical wisdom; (2) in constant flux; (3) sometimes wrong.

So what makes the DSM so important? In the United States, and in many other parts of the world, diagnoses and medical codes laid out in the DSM provide a basis for offering treatments, services, and medical insurance. The DSM also provides a means by which researchers in the mental health field can identify a group of people to study. Since there is no biological test for most mental disorders, researchers, insurers, and schools are stuck with observation of symptoms coupled with descriptions of disorders – and they generally go by the DSM (though there is another international coding system, the ICD, which is less often used in the United States).

DSM III (1980)

Autism as a disorder was first described in the DSM in 1980, though its name was “Infantile Autism.” As you can see, while it is similar to what we now think of as autism, it REQUIRES severe deficits in language development, which would rule out anyone with what we now think of as Asperger syndrome:

  • A. Onset before 30 months of age
  • B. Pervasive lack of responsiveness to other people (autism)
  • C. Gross deficits in language development
  • D. If speech is present, peculiar speech patterns such as immediate and delayed echolalia, metaphorical language, pronominal reversal.
  • E. Bizarre responses to various aspects of the environment, e.g., resistance to change, peculiar interest in or attachments to animate or inanimate objects.
  • F. Absence of delusions, hallucinations, loosening of associations, and incoherence as in Schizophrenia.
The term “autistic disorder” appeared in the DSM III-R, in 1987, with a long list of very specific criteria. Even then, though, there was no “autism spectrum,” nor were there high or low functioning designations.

DSM-IV (1994)

So when did the now-familiar diagnoses of Asperger syndrome and PDD-NOS (Pervasive Developmental Disorder Not Otherwise Specified) make it to the DSM? Incredibly, neither appeared until the DSM IV was published – in 1994!

Asperger syndrome and PDD-NOS, which described less severe or less clearly defined versions of autism, were expected to describe only a very small group of individuals who didn’t quite fit into the criteria described for full blown autism. There were no distinct boundaries between different diagnoses, but it was assumed that most people diagnosed with autism would fit the “classic” mold.

Much to the surprise of members of the committee who created the DSM IV and its later version the DSM IV-TR, the number of children with PDD-NOS and Asperger syndrome diagnoses ballooned after 1994. Numbers rose so quickly that autism was termed an “epidemic,” and major institutions were founded to cope with the huge rise in people with a once-rare diagnosis.

DSM-5 (2013)

In May 2013, the new DSM-5 was published. This version of the DSM creates a single Autism Spectrum, which includes not only people with “classic” autism (as per pre-1994 versions of the DSM) but also people with higher functioning autism.

Now, the symptoms of autistic disorder, Asperger syndrome, and PDD-NOS are now grouped together under the umbrella diagnosis of Autism Spectrum Disorder (ASD). To distinguish among the different “flavors” of autism, however, clinicians have the option of adding a functional level and specific descriptive language to your individual diagnosis. Here are the general diagnostic features for Autism Spectrum Disorder (you’ll find further details about the diagnostic features, levels, and specifiers in the DSM-5 in other articles):

  • A.Persistent deficits in social communication and social interaction across multiple contexts
  • B.Restricted, repetitive patterns of behavior, interests, or activities
  • C.Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life).
  • D.Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.
  • E.These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.


R. Grinker. Unstrange Minds Website, C. 2007.

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC.

DSM–III (1980) 3rd ed.
DSM–III–R (1987) 3rd ed., revised
DSM–IV (1994) 4th ed. DSM–IV–TR (2000) 4th ed., text rev.

  1. About.com
  2. Health
  3. Autism Spectrum Disorders
  4. Diagnosing Autism
  5. New Autism Criteria DSM 5
  6. Autism Diagnosis and the DSM

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