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Intellectual and Developmental Disabilities

This guide aims to provide background on IDD and the many contributing factors/diagnoses, as well as resources for student/faculty researchers and relevant organizations to be aware of.

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Language Choices

When working with individuals with intellectual and developmental disabilities, it's important to be aware of the terminology and way in which we speak about sensitive issues, especially with respect to identities. There are two primary ways that professionals and disabled individuals address language regarding disabilities: person-first language and identity-first language.


Person-First Language Identity-First Language
Person with a Disability Disabled Person
Adult with Autism Autistic Adult
People with Intellectual Disabilities Intellectually Disabled People
Child with a Disability Disabled Child

Person-First Language

The format of person-first language (PFL) is to literally put the person or people with the disability FIRST, before their disability status. Many see as the most respectful way of addressing people, especially in advocacy and clinical environments.

In a blog post for the National Aging and Disability Transportation Center, PFL is described as "a way to separate someone's diagnosis from their personhood" (Hawley, 2020). Some individuals express that PFL treats disability as something "shameful", and that placing emphasis on their humanity discredits the experiences that person has had due to their label of being disabled.

In response to this, some individuals prefer Identity-First Language.

Identity-First Language

Stemming from the Disability Pride movement, Identity-First Language instead emphasizes that a person’s disability or diagnosis is integral to their identity. They note that while Person-First Language (PFL) separates the person from their disability, this is not something that is possible in real life: a person who is disabled cannot be separated from it (Brown, 2011).

This may seem counterintuitive to what we already know about Person-First Language. While this is conflicting information, it's important as professionals, advocates, or self-advocates to know the ins and outs of the language used in the Disability Community.

Some people will be more comfortable with PFL; however, others will prefer to use Identity-First Language. It's recommended that if you're not sure which terminology to use, you should ask the individual if they have a preference. Knowing both of these terms and how to use them will help you in addressing members of your community with respect.

Tips for Searching Databases

When looking for research materials, a common issue one may run into is knowing which search terms to use. For general help on how to conduct a search, see the DUQSearch library guide.


Search Terms

Historically, individuals with intellectual and developmental disabilities have been mistreated and disregarded in several harmful ways, including poor healthcare practices, inhumane living conditions, institutionalization, and a lot of harmful stigma. Some of that stigma is perpetuated by antiquated diagnostic language.

The medical standard for labeling and diagnosing IDD previously involved several derogatory terms, including mental retardation, idiocy, and countless others. These terms have since been removed from diagnostic materials, but may pervade in the literature depending on publication date. If you're searching for articles that are older, inclusion of these harmful terms may be necessary in order to find relevant articles. In these special cases, it's important for authors to acknowledge the harmful connotations of any offensive or outdated terms. Use of offensive language should be justifiable in a research project.

As a professional in any field, it is important to address this population throughout your research with respect. Please consider using these terms:

  • Intellectual Disability
  • Intellectual Development Disorder
  • Intellectual and Developmental Disorders
  • Intellectual and Developmental Disabilities
  • If you are working specifically with a given diagnosis that falls under the category of IDD, use it instead.
    • Fragile X Syndrome
    • Down Syndrome
    • Rett Syndrome
    • Prader-Willi Syndrome
    • Williams Syndrome