Children's Hospital Colorado

Intellectual Disability

What is an intellectual disability?

Children with intellectual disability have unique personalities and learning styles. Most are happy and healthy. Children with intellectual disability learn and show developmental progress, although more slowly than others. They may take longer to learn to speak, walk, dress or eat by themselves. With ongoing support, a person with intellectual disability will function better and better over time. The term "intellectual disability" is used when a person’s intelligence and daily functioning are at a lower level than other people of the same age. The diagnosis also reflects how a child interacts with his or her environment and how much support is needed.

When a child is young, the term developmental delay is sometimes used to describe developmental skills that are lower than expected for a child’s age, such as language, motor, cognition or play. As a child becomes older, he or she may or may not "catch up" in all or some of these developmental skills. The term intellectual disability may then be used for some children, when it is felt that they will probably not totally catch up in their development. Other terms have been used in place of intellectual disability, such as cognitive disability. The term mental retardation previously was used.

What causes intellectual disability?

Intellectual disability has many different causes. Events that may be associated with the diagnosis can occur before, during or after birth.

The following factors can all cause or contribute to the occurrence of intellectual disability:

  • Genetic (inherited) conditions
  • Serious infections
  • Vascular (blood vessel) problems
  • Trauma (injury) to the brain
  • Metabolic (body chemistry) conditions
  • Exposure to toxins (such as lead or alcohol)

In some cases, it may be difficult or not possible to identify a specific cause.