Intellectual disability

Intellectual disability (ID), also known as general learning disability (in the <a href="/facts/United_Kingdom/kuPAILt2">United Kingdom</a>), and formerly mental retardation (in the <a href="/facts/United_States/P0sCdLe5">United States</a>), is a generalized <a href="/facts/Neurodevelopmental_disorder/vfBhK1S6">neurodevelopmental disorder</a> characterized by significant impairment in <a href="/facts/Intellect/oqUql3bD">intellectual</a> and <a href="/facts/Adaptive_functioning/FlETPXN7">adaptive functioning</a> that is first apparent during childhood. Children with intellectual disabilities typically have an <a href="/facts/Intelligence_quotient/rozfcXsk">intelligence quotient</a> (IQ) <a href="/facts/IQ_classification/IfKDNaBt">below 70</a> and deficits in at least two <a href="/facts/Adaptive_behavior/FlETPXN7">adaptive behaviors</a> that affect <a href="/facts/Everyday_life/2PsHYt5D">everyday living</a>. According to the <a href="/facts/DSM-5/kwhcSJcg">DSM-5</a>, intellectual functions include <a href="/facts/Reason/tcBImN8J">reasoning</a>, problem solving, <a href="/facts/Planning/ckzCp5tv">planning</a>, <a href="/facts/Abstraction/p7l9eHGd">abstract thinking</a>, judgment, academic learning, and learning from experience. 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. Deficits in adaptive functioning often compromise an individual's independence and ability to meet their social responsibility.
Intellectual disability is subdivided into syndromic intellectual disability, in which intellectual deficits associated with other medical and behavioral <a href="/facts/Signs_and_symptoms/BzP6MrTN">signs and symptoms</a> are present, and non-syndromic intellectual disability, in which intellectual deficits appear without other abnormalities. <a href="/facts/Down_syndrome/Y4XEQSMS">Down syndrome</a> and <a href="/facts/Fragile_X_syndrome/WWjbEWQE">fragile X syndrome</a> are examples of syndromic intellectual disabilities.
Intellectual disability affects about 2–3% of the general population. Seventy-five to ninety percent of the affected people have mild intellectual disability. Non-syndromic, or <a href="/facts/Idiopathic/YIVAonwA">idiopathic</a> cases account for 30–50% of these cases. About a quarter of cases are caused by a <a href="/facts/Genetic_disorder/hFqt2NLn">genetic disorder</a>, and about 5% of cases are <a href="/facts/Heredity/t0aMmRWx">inherited</a>. Cases of unknown cause affect about 95 million people as of 2013<a href="https://en.wikipedia.org/w/index.php?title=Intellectual_disability&action=edit">[update]</a>.

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Intellectual disability