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.
One in five adult Canadians (21.3 percent) will suffer a mental disorder in their lives This figure translates into 4.5 million people. 1 Anxiety disorders and depression are the most common. Approximately 2.5 million Canadian adults or over 10% of the population 18 and older will have a depressive disorder. All disorders 21%. Percentages will not total, as many people have symptoms in more than one category. Source: Bland et al, University of Alberta