APA Dictionary of Psychology

an older diagnostic category for those with IQs below 20, comprising about 1% of people with mental retardation, the older and offensive term for intellectual developmental disorder (intellectual disability). Included in DSM-IV-TR, it was considered to be due to sensorimotor abnormalities as well as intellectual factors; typical developmental attainments included rudimentary speech and limited self-care, and lifelong supervision in highly structured environments was needed. In DSM-5, the designation was changed to profound intellectual disability (intellectual developmental disorder), and, in DSM-5-TR, to profound intellectual developmental disorder (intellectual disability), with the level of severity defined on the basis of adaptive functioning, rather than IQ scores.