Intellectual disability (ID), also called intellectual development disorder (IDD) or general learning disability, and formerly known as mental retardation (MR) is a generalized neurodevelopmental disorder characterized by significantly impaired intellectual and adaptive functioning. It is defined by an IQ score below 70 in addition to deficits in two or more behaviors that affect every day, general living.
Pathophysiology: Sometimes disability is caused by abnormal genes inherited from parents, errors when genes combine, or other reasons eg. Down syndrome, Klinefelter's syndrome, Fragile X syndrome (common among boys), neurofibromatosis, congenital hypothyroidism. Intellectual disability can result when the fetus does not develop properly.
Diagnosis :The three criteria must be met for a diagnosis of intellectual disability: deficits in general mental abilities, significant limitations in one or more areas of adaptive behavior across multiple environments and evidence that the limitations became apparent in childhood or adolescence. In general, people with intellectual disability have an IQ below 70, but clinical discretion may be necessary for individuals who have a somewhat higher IQ but severe impairment in adaptive functioning.
The Global Burden of Disease Project estimated that the burden of mental disorders in Italy is relevant: 2978 DALYs per 100 000 can be attributed to neuropsychiatric disorders, about 25% of the overall burden of disease in the country. If only mental disorders are considered, they amount to 11% of the burden, on adding also dementia and substance abuse this increases to 21%. Depression alone amounts to 7% of the global burden, while bipolar disorder, schizophrenia, obsessive-compulsive disorder, panic disorder are each 1%.