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Mental Retardation

According to the American Association on Mental Deficiency, mental retardation is defined as subaverage general intellectual functioning that originates during the developmental period (prenatal to 16 years) and is associated with impairment in adaptive behavior.

Classification of Mental Retardation

There are many degrees of mental retardation. Persons who are severely retarded are able to learn only the most basic self-care skills. Those who are mildly retarded are able to learn so much that, as adults, some are no longer identified as being retarded. Three common classifications used include:

Mildly (Educable) -- Mental Age 8-12; learn to approximately 6th grade level.

Moderately (Trainable) -- Mental Age 5-8; cannot learn academic subjects in school.

Severely/Profoundly -- Many require life-long care and supervision and are often confined to institutions.


Not all the causes of mental retardation are known; however, more than 200 have been identified, and many others are suspected. The known causes can be placed into five categories:


A mentally retarded person is slow to learn and may be slow or limited in the development of physical skills. Additionally, physical handicaps may be present, such as speech impairments, visual impairments, hearing defects, or epilepsy. Reminder: Because these secondary handicapping conditions are common among people with mental retardation, this does not mean that individuals who have a speech impairment or epilepsy are mentally retarded.

Help For Leaders

It is often thought that it takes a certain kind of person or an individual with special education to work with people who are retarded. The fact is that anyone who is patient and kind and who has a sincere interest in working with people can be successful. As a volunteer, you can contribute greatly to the happiness and accomplishments of individuals who have mental retardation.


National Association for Down's Syndrome
P.O. Box 4542
Oak Brook, IL 60522
(630) 325-9112

The Arc
(a national organization on mental retardation)