Table 1.

Diagnostic Criteria for Intellectual Disability (Formerly Mental Retardation)

  1. Intellectual functioning significantly below the population mean (generally IQ score at least 2 standard deviations below the mean or <75)

  2. Significant limitation in adaptive skill areas (such that the patient cannot function adequately in their environment)–on standardized testing, at least 2 standard deviations below the mean in one of these areas or on a combined score of all three:

    • Conceptual (receptive and expressive language, reading and writing, money concepts, self-direction)

    • Social (interpersonal, responsibility, self-esteem, gullibility, naivete, following rules, obeying laws, avoiding victimization)

    • Practical (eating, bathing, dressing, toileting, meal preparation, telephone use, taking medications, managing money, transportation, occupational skills, maintaining a safe environment)

  3. Above limitations must be present and diagnosed before the age of eighteen

  • From the American Association of Intellectual and Developmental Disabilities (formerly American Association of Mental Retardation).