Intellectual disability is a condition diagnosed before age 18 that includes below-average intellectual function and a lack of skills necessary for daily living.
In the past, the term mental retardation was used to describe this condition. This term is no longer used.
Intellectual disability affects about 1% to 3% of the population. There are many causes of intellectual disability, but doctors find a specific reason in only 25% of cases.
Risk factors are related to the causes. Causes of intellectual disability can include:
As a family, you may suspect your child has an intellectual disability when your child has any of the following:
Signs of intellectual disability can range from mild to severe.
Developmental tests are often used to assess the child:
Goal of treatment is to develop the person's potential to the fullest. Special education and training may begin as early as infancy. This includes social skills to help the person function as normally as possible.
It is important for a specialist to evaluate the person for other physical and mental health problems. People with intellectual disability are often helped with behavioral counseling.
Discuss your child's treatment and support options with your health care provider or social worker so that you can help your child reach his or her full potential.
These resources may provide more information:
Outcome depends on:
Many people lead productive lives and learn to function on their own. Others need a structured environment to be most successful.
Call your provider if:
Genetic. Genetic counseling and screening during pregnancy can help parents understand risks and make plans and decisions.
Social. Nutrition programs can reduce disability associated with malnutrition. Early intervention in situations involving abuse and poverty will also help.
Toxic. Preventing exposure to lead, mercury, and other toxins reduces the risk of disability. Teaching women about the risks of alcohol and drugs during pregnancy can also help reduce risk.
Infectious diseases. Certain infections can lead to intellectual disability. Preventing these diseases reduces the risk. For example, rubella syndrome can be prevented through vaccination. Avoiding exposure to cat feces that can cause toxoplasmosis during pregnancy helps reduce disability from this infection.
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.