Mental retardation (MR), increasingly referred to as intellectual disability, can result from a variety of causes: congenital malformations, genetic, teratogenic, infectious, toxic, and perinatal factors, and postnatal complications. In one-quarter to one half of cases, it is impossible to attribute a particular child’s or adolescent’s MR to a single cause; in half of the children and adolescents for whom causal factors are known, there is more than one such factor (e.g., early bacterial meningitis and lack of intellectual stimulation in the home). The milder the MR, the more difficult it typically is to identify a specific etiology.
MR is defined as significant limitations in both intelligence and adaptive behavior, with onset before age 18. MR is characterized by significantly sub-average intellectual functioning (an intelligence quotient [IQ] of approximately 70 to 75 or below), existing concurrently with related limitations as expected for age and by the individual’s cultural group in two or more of the following applicable adaptive skill areas: communication, self-care, home living, social skills, use of community resources, self-direction, functional academic skills, work, leisure, health, and safety. Mental retardation reflects the “fit” between the capabilities of individuals and the structure and expectations of their environment. A valid assessment considers cultural and linguistic diversity as well as differences in communications and behavioral factors.1, 2
The life functioning of a child or teen with MR will generally improve if she has adequate and appropriate support, or resources and strategies that promote her interests and welfare. To improve functioning, a child or teen may need intermittent, limited, extensive, or pervasive support depending on the severity of MR; the level of support needed varies from individual to individual and over time. Support should focus on personal needs and aspirations instead of deficits. Primary care providers need to work together with children and adolescents with MR and their families to establish goals and to ensure that these children, teens, and families have the support they need to achieve these goals.3