How many people are affected by Intellectual Disability (mental retardation)?
Various studies have been conducted in local communities to determine the prevalence of mental retardation. The Arc reviewed many of these prevalence studies in the early 1980s and concluded that 2.5 to 3 percent of the general population has intellectual disability (mental retardation) (The Arc, 1982). A 1993 review of prevalence studies generally confirms this distribution (Fryers, 1993). Based on the 1990 census, an estimated 6.2 to 7.5 million people have intellectual disability. Intellectual Disability is 12 times more common than cerebral palsy and 30 times more prevalent than neural tube defects such as spina bifida. It affects 100 times as many people as total blindness (Batshaw & Perret, 1992). Intellectual Disability cuts across the lines of racial, ethnic, educational, social and economic backgrounds. It can occur in any family. One out of ten American families is directly affected by intellectual disability.
