Intellectual Disabilities


Intellectual Disabilities


Our nation’s special education law, the Individuals with Disabilities Education Act (IDEIA) defines intellectual disability as...

“...significantly subaverage general intellectual functioning existing concurrently with deficits in adaptive behavior. And manifested during the developmental period that adversely affects a child's educational performance.”

[34 Code of Federal Regulations §300.8(c)(6)]

“Intellectual Disability” is a new term in IDEA. Until October 2010, the law used the term “mental retardation.” In October 2010, President Obama signed Rosa’s Law, changing the term to be used in the future to “intellectual disability.” The definition of the term itself did not change. (NICHCY)


Intellectual disability is the most common developmental disability. Approximately 6.4 million people in the United States have an intellectual disability. More than 545,000 children (ages 6-21) have some level of intellectual disability and receive special education services in public school under this category in IDEA, the nation’s special education law. In fact, one in every ten children who need special education have some form of intellectual disability. (NICHCY)


Intellectual disabilities are diagnoses by looking at two things: the ability of a person’s brain to learn, think, solve problems, and make sense of the work (called IQ or intellectual functioning); and whether the person has the skills he or she needs to live independently (called adaptive behavior or adaptive functioning).

Intellectual functioning, or IQ, is usually measured by a test called an IQ test. The average score is 100. People scoring below 70 to 75 are thought to have an intellectual disability. To measure adaptive behavior, professionals look at what a child can do in comparison to other children of his or her age. (NICHCY)


The most common causes of intellectual disabilities are:


There are many signs of an intellectual disability including:


At this time, there is no cure for intellectual disabilities. (NICHCY)


A child with an intellectual disability can do well in school but is likely to need the individualized help that’s available as special education and related education services. The level of help and support that’s needed will depend upon the degree of intellectual disability involved.

Strategies for Teachers

Strategies for Parents


American Association of Intellectual and Developmental Disabilities

501 3rd Street, NW
Suite 200
Washington, D.C. 20001

AAIDD promotes progressive policies, sound research, effective practices, and universal human rights for people with intellectual and developmental disabilities.

The Arc of the United States 

1825 K Street, NW,
Suite 1200
Washington, DC 20006 

With 1,000 chapters in the U.S., The Arc of the United States is the country's largest voluntary organization committed to the welfare of children and adults with mental retardation and their families. This organization provides information about educational campaigns and other materials that are helpful to parents and educators. Also, you can connect with a local chapter through the website.