Developmental Disabilities

Type of psychology: Developmental psychology
Fields of study: Childhood and adolescent disorders; cognitive
development; infancy and childhood; organic disorders
Developmental disabilities are conditions that result in substantial functional limitations.

They manifest themselves in childhood and persist throughout the life span, requiring
a continuum of medical, educational, and social services.

Key concepts
• activities of daily living (ADLs)
• individual education plan (IEP)
• individual family service plan (IFSP)
• medically fragile
• mental retardation
• pervasive developmental disorder (PDD)

The concept of developmental disabilities was first introduced in the Developmental
Disabilities Services and Facilities Construction Act of 1970. Subsequently,
the Developmental Disabilities Assistance and Bill of Rights Act of
1990 defined developmental disabilities. The term “developmental disability”
means a severe, chronic disability of a person five years of age or older
that is attributable to a mental or physical impairment or a combination of
both. The disability must manifest itself before the person reaches the age of
twenty-two and be expected to continue indefinitely. It results in substantial
functional limitations in three or more areas of major life activity, including
self-care, receptive and expressive language, learning, mobility, selfdirection,
capacity for independent living, and economic self-sufficiency.

The inclusion of the requirement of substantial functional limitations in
three or more major life areas forms the basis for provision of services to individuals
with severe impairments.
The American Psychiatric Association does not use the term “developmental
disabilities.” However, it does identify pervasive developmental disorders
(PDD) in its diagnostic manual. The description of these disorders
and their manifestations in many ways overlaps the definition of developmental
disabilities.

The terms “developmental disabilities” and “mental retardation” are often
used as if they were synonymous. However, there are important distinctions
as well as areas of overlap. The President’s Committee on Mental
Retardation uses the definition developed and used by the American Association
on Mental Retardation and generally understood by the Arc-USA
(a national organization for people with mental retardation and related developmental
disabilities and their families). Developmental disabilities include
more disabilities than those encompassed under mental retardation.

Developmental disabilities comprise severe and chronic disabilities, while
mental retardation includes a large number of individuals functioning at
the mild level of cognitive impairment who require little or no support in
adulthood. However, mental retardation does account for 70 percent of the
people who are developmentally disabled. The term “medically fragile” is
sometimes used to describe those vulnerable individuals whose complex
medical needs can seriously compromise their health status.