The Oxford Biblical Studies Online and Oxford Islamic Studies Online have retired. Content you previously purchased on Oxford Biblical Studies Online or Oxford Islamic Studies Online has now moved to Oxford Reference, Oxford Handbooks Online, Oxford Scholarship Online, or What Everyone Needs to Know®. For information on how to continue to view articles visit the subscriber services page.

Related Content

More Like This

Show all results sharing this subject:

  • Medicine and health


Show Summary Details


mental retardation

Quick Reference

A mental disorder characterized by arrested or incomplete mental development, with onset before age 18, leading to significantly below-average intellectual functioning (specifically, IQ below 70), accompanied by deficits in adaptive functioning in such areas as interpersonal communication, self-care, home living, social skills, use of public amenities, self-direction, scholastic or academic performance, work, leisure, health, or safety. According to the World Health Organization, an IQ between 50 and 70 is approximately indicative of mild mental retardation, 35–50 moderate mental retardation, 20–35 severe mental retardation, and below 20 profound mental retardation. See cerebral gigantism, cerebral palsy, cretinism, cri du chat, Down's syndrome, foetal alcohol syndrome, fragile X syndrome, Hurler's syndrome, idiot savant, Klinefelter's syndrome, Lesch-Nyhan syndrome, macrocephaly, microcephaly, mild mental retardation, moderate mental retardation, phenylketonuria, profound mental retardation, severe mental retardation, Tay-Sachs disease, Williams syndrome, zombie (2). See also savant. Compare borderline intelligence. MR abbrev.

Reference entries