APA Dictionary of Psychology

a historical, outdated, and now considered offensive term for the diagnosis made when an individual is presumed to have intellectual developmental disorder but is too severely impaired or uncooperative to be evaluated through the use of standard intelligence tests and adaptive behavior measures. The DSM–IV–TR designation is mental retardation, severity unspecified. In DSM-5, the designation was changed to unspecified intellectual disability (intellectual developmental disorder), and, in DSM-5-TR, to unspecified intellectual developmental disorder (intellectual disability).