Policy Responses to Rising Autism Diagnoses in Childhood

Annex A. Evolution of autism diagnosis criteria in DSM and ICD (1952‑2022)

Table A A.1. Autism as a subtype of schizophrenia (1952‑1980)

Diagnostic manual	Diagnostic and Statistical Manual: Mental Disorders (DSM-I)	Diagnostic and Statistical Manual, 2nd edition (DSM-II)	International Classification of Diseases, 9th edition, Clinical Modification (ICD‑9)
Year	1952	1968	1977
Type	Schizophrenia	Schizophrenia	Psychosis with origin specific to childhood
Subtypes	Schizophrenic Reaction, Childhood Type (manifesting primarily as autism)	Schizophrenia, childhood type (may be manifested by autistic behaviour)	Infantile autism

Source: APA (1952[1]), Diagnostic and Statistical Manual: Mental Disorders (DSM-I); APA (1968[2]), Diagnostic and Statistical Manual of Mental Disorders, Second edition (DSM-II); WHO (1977[3]), International Classification of Diseases, 9th edition (ICD‑9).

Table A A.2. Autism as pervasive developmental disorder (PDD) (1980‑2013)

Diagnostic manual	Diagnostic and Statistical Manual, 3rd edition (DSM-III)	Diagnostic and Statistical Manual, 3rd edition, Revised (DSM-III-R)	International Classification of Diseases, 10th edition (ICD‑10)	Diagnostic and Statistical Manual, 4th edition (DSM-IV)
Published	1980	1987	1992	1994
Type	Pervasive developmental disorder (PDD)	Pervasive developmental disorder (PDD)	Pervasive developmental disorder (PDD)	Pervasive developmental disorder (PDD)
Subtypes	1. Infantile autism (onset before age 30 months) 2. Childhood-onset PDD (onset after age 30 months) 3. Atypical PDD (autistic-like condition) 4. Residual infantile autism	1. Autistic disorder (roughly corresponds to infantile autism) 2. Pervasive developmental disorder, not otherwise specified (PDD-NOS)	1. Childhood autism 2. Atypical autism 3. Rett syndrome 4. Other childhood disintegrative disorder 5. Overactive disorder associated with mental retardation and stereotyped movements 6. Asperger syndrome 7. Other PDDs 8. PDD-NOS	1. Autistic disorder 2. Rett’s disorder* 3. Childhood disintegrative disorder 4. Asperger’s syndrome 5. PDD-NOS (including atypical autism)

Note: *In the text revision of the DSM-IV, Rett’s disorder was classified as a separate genetic disorder, distinct from autism (APA, 2000[4]).

Source: APA (1980[5]), Diagnostic and Statistical Manual, Third edition (DSM-III); APA (1987[6]), Diagnostic and Statistical Manual, Third edition, Revised (DSM-III-R); APA (1994[7]), Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV); WHO (1992[8]), International Classification of Diseases, 10th edition (ICD‑10).

Table A A.3. Autism spectrum disorder (ASD) (2013‑current)

Diagnostic manual	Diagnostic and Statistical Manual, 5th edition (DSM‑5)*	International Classification of Diseases, 11th edition (ICD‑11)
Published	2013	2019
Type	Neurodevelopmental disorders (NDD)	Neurodevelopmental disorders (NDD)
Subtypes	Autism spectrum disorder (ASD) (severity levels 1, 2 and 3)	Autism spectrum disorder (ASD)

Note: *The text revision of the DSM‑5 added elements related to culture and sex and gender, as well as co‑occurring conditions (APA, 2022[9]).

Source: APA (2013[10]), Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM‑5), https://psychiatryonline.org/doi/book/10.1176/appi.books.9780890425596; WHO (2019[11]), International Classification of Diseases, 11th edition (ICD‑11), https://icd.who.int/browse/2025-01/mms/en.

References

[9] APA (2022), Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), American Psychiatric Association, Arlington, VA, https://doi.org/10.1176/appi.books.9780890425787.

[10] APA (2013), Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), American Psychiatric Association, Arlington, VA, https://psychiatryonline.org/doi/book/10.1176/appi.books.9780890425596.

[4] APA (2000), Diagnostic and Statistical Manual of Mental Disorders, Fourth edition, Text Revision (DSM-IV-TR), American Psychiatric Association, Arlington, VA.

[7] APA (1994), Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), American Psychiatric Association, Arlington, VA, https://doi.org/10.1176/appi.books.9780890420614.dsm-iv.

[6] APA (1987), Diagnostic and Statistical Manua lof Mental Disorders, Third edition, Revised (DSM-III-R), American Psychiatric Association, Arlington, VA.

[5] APA (1980), Diagnostic and Statistical Manual of Mental Disorders, Third edition (DSM-III), American Psychiatric Association, Arlington, VA.

[2] APA (1968), Diagnostic and Statistical Manual of Mental Disorders, Second edition (DSM-II), American Psychiatric Press, Washington, DC.

[1] APA (1952), Diagnostic and Statistical Manual: Mental Disorders (DSM-I), American Psychiatric Association, Washington, D.C.

[11] WHO (2019), International Classification of Diseases, 11th edition (ICD-11), World Health Organization, Geneva, https://icd.who.int/browse/2025-01/mms/en (accessed on 6 February 2025).

[8] WHO (1992), International Classification of Diseases, 10th edition (ICD-10), World Health Organization, Geneva.

[3] WHO (1977), International Classification of Diseases, 9th edition (ICD-9), World Health Organization, Geneva.