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Intellectual & Developmental Disorders

What are Intellectual & Developmental Disorders?

People with intellectual and/or developmental disabilities often experience challenges in their learning, communication and daily functioning. There is a lot of levels in the severity of intellectual and developmental disabilities, from mild (where individuals may require some support, but are generally independent) to profound (where individuals are mostly dependent on others for support). The level of disability is typically determined by the level of a person’s “adaptive functioning” rather than an IQ test, which refers to skills that are learned to help the person manage in their everyday lives, compared to a person of similar age, gender and socio-cultural origins.

Intellectual and developmental disabilities stem from genetic and physiological causes before birth or in one’s early years. Symptoms of such a disability are typically displayed during childhood development.


As there are many different kinds of intellectual and developmental disabilities of differing levels of severity, symptoms can widely differ. The diagnostic criteria for determining such a disability includes:

  • Intellectual deficits
  • Adaptive functioning deficits
  • Deficits noted during childhood development


Supporting individuals with intellectual and developmental disabilities has to be tailored to the individual and their familial needs, due to differing levels of severity and adaptive functioning skills. Dalton Associates can help you find a psychologist, psychological associate, and/or mental health professionals who can provide comprehensive assessment, family therapy and skill development, and counselling support for individuals and their families affected by intellectual and developmental disabilities.


American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders: DSM-5. Washington, D.C: American Psychiatric Association.
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