Intellectual disability, also known as mental retardation, affects peoples’ capacity to develop cognitive and adaptive skills.  The extent of disability that people can have ranges from mild, to moderate, severe, and profound.  People with mild intellectual disability are generally able to learn many skills, although they learn more slowly, and they are generally less aware of how to interact socially. With enough support, they can live on their own as adults and hold down a job.  About 90% of people with intellectual disability have a mild degree of impairment. 

People who have moderate intellectual disability are generally able to learn to care for themselves with special training and, as adults, can often develop some independence in their daily living skills, and work with supervision.  People who have severe or profound intellectual disability exhibit more serious deficits in speech, coordination, and ability to learn, and they frequently have physical handicaps.  Some of these people need constant care and supervision, but others can learn to perform useful tasks and many, as adults, can perform some types of work with supervision.