Subnormal intellectual functioning which originates during the developmental period. This has multiple potential etiologies, including genetic defects and perinatal insults. Intelligence quotient (IQ) scores are commonly used to determine whether an individual has an intellectual disability. IQ scores between 70 and 79 are in the borderline range. Scores below 67 are in the disabled range. (from Joynt, Clinical Neurology, 1992, Ch55, p28)

Synonyms: Intellectual Development Disorders, Mental Retardation, Psychosocial, Psychosocial Mental Retardations, Intellectual Development Disorder, Development Disorder, Intellectual, Psychosocial Mental Retardation, Mental Deficiency, Mental Retardation, Deficiency, Mental, Disability, Intellectual, Retardation, Mental, Mental Deficiencies, Retardation, Psychosocial Mental, Intellectual Disabilities, Development Disorders, Intellectual, Idiocy, Disorders, Intellectual Development, Deficiencies, Mental, Retardations, Psychosocial Mental, Disabilities, Intellectual, Disorder, Intellectual Development, Intellectual Disability, Mental Retardations, Psychosocial