Mental Retardation - Description

Mental retardation is defined by two standards. The first standard is a person's level of intelligence. Intelligence levels are usually measured by special tests called intelligence tests. Intelligence tests provide a numerical ranking of a person's mental abilities. That ranking is called an intelligence quotient or, more commonly, an IQ. In general, a person with an IQ score of less than 75 is said to be retarded.

The second standard for mental retardation is adaptive skills. The term "adaptive skills" means how well a person can deal with the tasks of everyday life. These tasks include the ability to speak and understand; home-living skills; use of community resources; leisure, self-care, and social skills; self-direction; basic academic skills (reading, writing, and arithmetic); and work skills. A person is regarded as mentally retarded if he or she is unable to dress, feed, wash, or otherwise care for him- or herself; to hold a job; or to carry out most of the other tasks needed to get through an ordinary day.

Mental-health professionals classify patients into one of four levels of retardation.

Mild Mental Retardation

• IQ scores from 50 to 75
• Includes about 85 percent of the mentally retarded population
• Individuals in this group can often live on their own with community support.

Moderate Mental Retardation

• IQ scores between 35 and 50
• Includes about 10 percent of the mentally retarded population
• Individuals in this group can often lead relatively normal lives provided they receive some level of supervision. Such individuals often live in group homes with other mentally retarded people.

Severe Mental Retardation

• IQ scores between 20 and 35
• Includes about 3 percent to 4 percent of the mentally retarded population
• Individuals in this category can often master the most basic skills of living, such as cleaning and dressing themselves. They often live in group homes.

Profound Mental Retardation

• IQ scores of less than 20
• Includes about 1 percent to 2 percent of the mentally retarded population
• Individuals at this level can often develop basic communication and self-care skills. They often have other mental disorders.