Intellectual disability (ID), also known as general learning disability (in the United Kingdom[3]) and formerly mental retardation (in the United States[4]),[5][6] is a generalized neurodevelopmental disorder characterized by significant impairment in intellectual and adaptive functioning that is first apparent during childhood. Children with intellectual disabilities typically have an intelligence quotient (IQ) below 70 and deficits in at least two adaptive behaviors that affect everyday, general living. According to the DSM-5, intellectual functions include reasoning, problem solving, planning, abstract thinking, judgment, academic learning, and learning from experience.[7] Deficits in these functions must be confirmed by clinical evaluation and individualized standard IQ testing. On the other hand, adaptive behaviors include the social, developmental, and practical skills people learn to perform tasks in their everyday lives.[8] Deficits in adaptive functioning often compromises an individual's independence and ability to meet their social responsibility.[9]
Intellectual disability is subdivided into syndromic intellectual disability, in which intellectual deficits associated with other medical and behavioral signs and symptoms are present, and non-syndromic intellectual disability, in which intellectual deficits appear without other abnormalities.[10]Down syndrome and fragile X syndrome are examples of syndromic intellectual disabilities.
Intellectual disability affects about 2–3% of the general population.[11] Seventy-five to ninety percent of the affected people have mild intellectual disability.[11] Non-syndromic, or idiopathic cases account for 30–50% of these cases.[11] About a quarter of cases are caused by a genetic disorder,[11] and about 5% of cases are inherited.[12] Cases of unknown cause affect about 95 million people as of 2013[update].[13]
^Tidy, Colin (25 January 2013). "General Learning Disability". Patient.info. Archived from the original on 27 June 2015. The term general learning disability is now used in the UK instead of terms such as mental handicap or mental retardation. The degree of disability can vary significantly, being classified as mild, moderate, severe or profound.
^Ansberry, Clare (20 November 2010). "Erasing a Hurtful Label From the Books". The Wall Street Journal. Archived from the original on 27 June 2015. Retrieved 4 December 2010. Decades-long quest by disabilities advocates finally persuades state, federal governments to end official use of 'retarded'.
^Boat, Thomas F.; Wu, Joel T.; Disorders, Committee to Evaluate the Supplemental Security Income Disability Program for Children with Mental; Populations, Board on the Health of Select; Board on Children, Youth; Medicine, Institute of; Education, Division of Behavioral and Social Sciences and; The National Academies of Sciences, Engineering (2015-10-28), "Clinical Characteristics of Intellectual Disabilities", Mental Disorders and Disabilities Among Low-Income Children, National Academies Press (US), retrieved 2024-04-13