(Cognitive Disability; Developmental Disability; Mental Retardation)
Intellectual disability is when a person has limits in:
- Intellectual function—learning, reasoning, and problem solving
- Adaptive behavior—daily tasks, such as communication and taking care of daily needs
The cause is not always known. The most common ones are:
- Genetic problems, such as Down syndrome and Fragile X syndrome
- Metabolic problems, such as phenylketonuria (PKU) and congenital hypothyroidism
- Problems with brain development, such as hydrocephalus and malformation
- Infections during pregnancy, such as toxoplasmosis, HIV, and rubella
- Unhealthy habits during pregnancy, such as substance and alcohol use disorder
- Problems at birth, such as being born very early or not getting enough oxygen
- Problems during childhood, such as:
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This problem is more common in people who have other family members who have it. The risk is also higher in people who have any of the known causes.
Symptoms start before a child reaches age 18. Problems may be mild to severe. It varies from person to person.
Problems may be:
- Learning and developing more slowly than other children of the same age
- Problems communicating or socializing with others
- Trouble learning in school
- Problems doing everyday things like getting dressed or using the bathroom without help
- Problems hearing, seeing, walking, or talking
- Problems making decisions
The doctor will ask about your child’s symptoms and health history. A physical exam will be done. Tests will be given to measure intellectual function and adaptive behavior.
Children with this problem have a higher risk for other disabilities. More tests may be done to look for these problems.
There is no cure. The goal of treatment is to improve function and quality of life. This may allow some people to work and live on their own. Others may need support throughout their lives.
Treatment should be started early. Choices are:
- Speech, physical, and occupational therapy
- School-based services to help the child succeed in class
- Job skills training
Proper prenatal care may lower the risk of some causes.
Canadian Psychological Association
Special Olympics Canada
Facts about intellectual disability. The Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/ncbddd/developmentaldisabilities/facts-about-intellectual-disability.html. Accessed January 27, 2021.
Intellectual disabilities in children—approach to the patient. EBSCO DynaMed website. Available at: https://www.dynamed.com/approach-to/intellectual-disabilities-in-children-approach-to-the-patient. Accessed January 27, 2021.
Purugganan O. Intellectual Disabilities. Pediatr Rev. 2018 Jun;39(6):299-309.
Questions and answers about persons with intellectual disabilities in the workplace. US Equal Employment Opportunities Commission website. Available at: http://www.eeoc.gov/laws/types/intellectual_disabilities.cfm. Accessed January 27, 2021.
Last reviewed December 2020 by EBSCO Medical Review Board Rimas Lukas, MD Last Updated: 1/27/2021