Last Updated on May 03, 2014


Intellectual disability is a developmental delay that is significantly below average compared to peers, in terms of intelligence and adaptive skills.

The American Association on Intellectual and Developmental Disabilities has defined Intellectual disability as: disability characterized by significant limitations in both intellectual functioning and inadaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18.

Intelligent Quotient, or IQ, is an intelligence test score that is obtained by dividing mental age by chronological age and multiplying by 100. The measure of intelligence of a person is derived from results obtained from specially designed and standardized tests. The mental age refers to the age-graded level of performance as derived from population norms. The evaluation of the individualís ability to perform in terms of three-dimensional thinking, language fluency, reasoning ability and many others is done. Thus, the intelligence quotient indicates the level of performance of the person for the particular age group.

Intellectual disability is not a disease, nor is it a mental illness. It is a condition indicated by an Intelligent Quotient of 70 or below, and has recently been termed as intellectual disability. Intellectual disability is subdivided into syndromic intellectual disability and non-syndromic intellectual disability. The former refers to the intellectual deficits co-existing with other medical and behavioral abnormalities, and in the latter condition, the intellectual deficits appear without other abnormalities.

About one-third of the intellectually disabled need institutional care, all others can do some kind of work. However, as children, they develop slower and by the time they grow up, they are far behind their peers. In the work place, they are able to do simple, repetitive jobs, but usually need more time to adjust to the environment and role.

Facts on Intellectual disability

1. Intellectual disability, earlier known as mental retardation, means that a personís mental development is much less than peers.

2. The name for the condition has been changed in 2010, as the term mental retardation seemed to have negative connotations.

3. Intellectual disability is not a disease, nor is it contagious.

4. More than 250 causes of intellectual disability have been discovered.

5. Intellectual disabilities are 25 times more common than blindness.

6. Children with intellectual disability usually have delayed developmental milestones.

7. Diagnosis of intellectual disability is based on combination of the personís intelligence quotient, developmental delay and adaptive skills.

8. In new or unfamiliar environments, the individual requires more time to adapt and follow new directions.

9. Rehabilitative measures for the intellectually disabled include training in basic skills, self-help skills and placement on simple, repetitive jobs.

10. Institutions for the intellectually disabled offer specialized services. Schools include teaching curriculum, money-matters, and daily skills.

11. Some institutions offer placement services for the intellectually disabled, training them in commuting from home to work place and the job-specific skills.

12. Intellectually disabled also have emotions and feelings as others. They show desire to learn and pride in their work.

13. An intellectually disabled person is equal in sexual promiscuous as others.

14. Individuals with intellectual disability are not always violent or engage in criminal or unpredictable behaviors.


  1. Intellectual disability - (
  2. Department of Child & Adolescent Psychiatry - (

Latest Publications and Research on Intellectual disability

Do you wish to consult Pediatrician for your problem? Ask your question

Most Popular on Medindia