About I/D Disabilities
What is intellectual disability?
Intellectual disability is a disability characterized by significant limitations both in intellectual functioning (reasoning, learning, problem solving) and in adaptive behavior, which covers a range of everyday social and practical skills. This disability originates before the age of 18.
Is intellectual disability the same as developmental disabilities?
“Developmental Disabilities” is an umbrella term that includes intellectual disability but also includes other disabilities that are apparent during childhood.
Developmental disabilities are severe chronic disabilities that can be cognitive or physical or both. The disabilities appear before the age of 22 and are likely to be lifelong. Some developmental disabilities are largely physical issues, such as cerebral palsy or epilepsy. Some individuals may have a condition that includes a physical and intellectual disability, for example Down syndrome or fetal alcohol syndrome.
Intellectual disability encompasses the “cognitive” part of this definition, that is, a disability that is broadly related to thought processes. Because intellectual and other developmental disabilities often co-occur, intellectual disability professionals often work with people who have both types of disabilities.
Is intellectual disability determined by just an IQ test?
No. The evaluation and classification intellectual disability is a complex issue. There are three major criteria for intellectual disability: significant limitations in intellectual functioning, significant limitations in adaptive behavior, and onset before the age of 18.
The IQ test is a major tool in measuring intellectual functioning, which is the mental capacity for learning, reasoning, problem solving, and so on. A test score below or around 70—or as high as 75—indicates a limitation in intellectual functioning.
Other tests determine limitations in adaptive behavior, which covers three types of skills:
- Conceptual skills—language and literacy; money, time, and number concepts; and self-direction
- Social skills—interpersonal skills, social responsibility, self-esteem, gullibility, naïveté (i.e., wariness), social problem solving, and the ability to follow rules, obey laws, and avoid being victimized
- Practical skills—activities of daily living (personal care), occupational skills, healthcare, travel/transportation, schedules/routines, safety, use of money, use of the telephone
What causes intellectual disability?
There are a number of causes. Our understanding of the causes of intellectual disability focuses on the types of risk factors (biomedical, social, behavioral, and educational) and the timing of exposure (prenatal, perinatal, and postnatal) to those factors.