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Cited by 212Autism Spectrum Disorder ResearchDown syndrome and intellectual disability researchGenetics and Neurodevelopmental Disorders

Autism and intellectual disability: a study of prevalence on a sample of the Italian population

La Malfa, G., Lassi, S., Bertelli, M., Salvini, R., Placidi, G. F.·2004·Journal of Intellectual Disability Research
DOI 10.1111/j.1365-2788.2003.00567.x
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Abstract

BACKGROUND: In 1994, the American Association on Mental Retardation with the DSM-IV has come to a final definition of pervasive developmental disorders (PDD), in agreement with the ICD-10. Prevalence of PDD in the general population is 0.1-0.15% according to the DSM-IV. PDD are more frequent in people with severe intellectual disability (ID). There is a strict relationship between ID and autism: 40% of people with ID also present a PDD, on the other hand, nearly 70% of people with PDD also have ID. We believe that in Italy PDD are underestimated because there is no agreement about the classification system and diagnostic instruments. METHOD: Our aim is to assess the prevalence of PDD in the Italian population with ID. The Scale of Pervasive Developmental Disorder in Mentally Retarded Persons (PDD-MRS) seems to be a very good instrument for classifying and diagnosing PDD. RESULTS: The application of the PDD-MRS and a clinical review of every individual case on a sample of 166 Italian people with ID raised the prevalence of PDD in this population from 7.8% to 39.2%. CONCLUSIONS: The study confirms the relationship between ID and autism and suggests a new approach in the study of ID in order to elaborate a new integrated model for people with ID.

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  • All studies included in the present review involved individuals without intellectual disability, thus excluding a large proportion of the autism spectrum disorder population.

    “All the studies included in the present review involved individuals without in­ tellectual disability, thus excluding a large proportion of the ASD pop­ ulation (La Malfa et al., 2004; Matson and Shoemaker, 2009).”

    From Predictive coding in neuropsychiatric disorders: a systematic transdiagnostic review. (2025) · cites this paper as La Malfa et al., 2004

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Authors
La Malfa, G., Lassi, S., Bertelli, M., Salvini, R., & Placidi, G. F.
Affiliations
Azienda Ospedaliero-Universitaria Careggi (IT)
ORCID
Venue
Journal of Intellectual Disability Research
Publisher
Wiley
Published
2004-03
Volume
48
Issue
3
Pages
262-267
ISSN
  • 0964-2633 (ISSN-L)
  • 1365-2788
DOI
10.1111/j.1365-2788.2003.00567.x
OpenAlex
W1978444163
Cited by
212
References
36
Citations by year
2026: 2 · 2025: 2 · 2024: 8 · 2023: 14 · 2022: 12 · 2021: 12 · 2020: 16 · 2019: 17 · 2018: 12 · 2017: 14 · 2016: 13 · 2015: 13 · 2014: 13 · 2013: 15 · 2012: 13
FWCI
2.52
Type
journal article
Language
en
Open access
closed
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor, 15 d)
Locations
  • Journal of Intellectual Disability Research (publishedVersion)
  • PubMed (publishedVersion)
  • Florence Research (University of Florence) (submittedVersion)
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Autism Spectrum Disorder Research
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Down syndrome and intellectual disability research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetics and Neurodevelopmental Disorders
Keywords
autism spectrum disorder, intellectual disability, pervasive developmental disorders, prevalence, diagnostic classification, underdiagnosis
MeSH terms
Adolescent, Adult, Aged, Aged, 80 and over, Autistic Disorder, Female, Humans, Italy, Male, Intellectual Disability, Middle Aged, Surveys and Questionnaires, Prevalence, Diagnostic and Statistical Manual of Mental Disorders

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