To be diagnosed with mental retardation, symptoms must be present in childhood. Adults who experience a loss in cognitive functioning may be diagnosed with another illness such as dementia. A number of factors can cause mental retardation, including:

Down Syndrome and fetal alcohol syndrome significantly increase a person’s risk of mental retardation, though not all people with these conditions have mental retardation.

Improper development during pregnancy can contribute to the development of symptoms, and exposure to certain drugs in utero—particularly illegal drugs and