Mental retardation

Mental retardation (abbreviated as MR), is a term for a person who has limitations in mental functioning and in skills such as communicating, taking care of him or herself, and social skills. A general, defined condition with various symptoms, caused by a lack of development of the brain before birth. These limitations will cause a child to learn and develop more slowly than a typical child. Children with mental retardation may take longer to learn to speak, walk, and take care of their personal needs such as dressing or eating. They are likely to have trouble learning in school. They will learn, but it will take them longer. There may be some things they cannot learn.

Mental deficiency is the condition of a person deemed to possess a level of intellectual capacity that is so far below normal as to seriously impact the individual's ability to function in society.

There are three criteria before a person is considered to have mental retardation, their IQ is below 75, they have significant limits in two or more adaptive behavioral areas, and they have been so afflicted since childhood. Down syndrome, fetal alcohol syndrome and fragile X are the three most common causes of mental retardation.

Mental retardation is not a disease. Mental retardation is also not a type of mental illness, such as depression. There is no cure for mental retardation. However, most children with mental retardation can learn to do many things. It just takes them more time and effort than other children.

Signs of Mental Retardation

There are many signs of mental retardation. For example, children with mental retardation may:

• sit up, crawl, or walk later than other children;
• learn to talk later, or have trouble speaking,
• find it hard to remember things,
• not understand how to pay for things,
• have trouble understanding social rules,
• have trouble seeing the consequences of their actions,
• have trouble solving problems, and/or
• have trouble thinking logically.

About 87 percent of people with mental retardation will only be a little slower than average in learning new information and skills. When they are children, their limitations may not be obvious. They may not even be diagnosed as having mental retardation until they get to school. As they become adults, many people with IQ or intellectual functioning); and

• whether the person has the skills he or she needs to live independently (called adaptive behavior, or adaptive functioning).

Intellectual functioning, or IQ, is usually measured by a test called an IQ test. The average score is 100. People scoring below 70 to 75 are thought to have mental retardation. To measure adaptive behavior, professionals look at what a child can do in comparison to other children of his or her age. Certain skills are important to adaptive behavior. These are:

• daily living skills, such as getting dressed, going to the bathroom, and feeding one's self;
• communication skills, such as understanding what is said and being able to answer;
• social skills with peers, family members, adults, and others.

To diagnose mental retardation, professionals look at the person's mental abilities (IQ) and his or her adaptive skills.

Causes of Mental Retardation

Doctors have found many causes of mental retardation. The most common are:

• Genetic conditions. Sometimes mental retardation is caused by abnormal genes inherited from parents, errors when genes combine, or other reasons. Examples of genetic conditions include Down syndrome, Fragile X syndrome, and phenylketonuria (PKU).
• Problems during pregnancy. Mental retardation can result when the baby does not develop inside the mother properly. For example, there may be a problem with the way the baby's cells divide as it grows. A woman who drinks alcohol (see fetal alcohol syndrome) or gets an infection like rubella during pregnancy may also have a baby with mental retardation.
• Problems at birth. If a baby has problems during labor and birth, such as not getting enough oxygen, he or she may have mental retardation.
• Health problems. Diseases like whooping cough, the measles, or meningitis can cause mental retardation. Mental retardation can also be caused by extreme malnutrition (not eating right), not getting enough medical care, or by being exposed to poisons like lead or mercury.

Traditional terms

The three traditional terms denoting varying degrees of mental deficiency long predate psychiatry. They were originally used in English as simple forms of abuse, and this is still the main usage. Their now obsolete use as psychiatric technical definitions is of purely historical interest. There have been some efforts made among mental health professionals to discourage use of these terms.

• Idiot stems from Gr. Idiotos - someone who does not participate in politics. The term now indicates the greatest degree of mental deficiency, where the mental age is 2 years or less, and the person cannot guard himself against common physical dangers. The term is gradually being replaced by the term profound mental retardation.

An 'idiot' is the corresponding term for a person affected by idiocy.

The word idiot comes from the Greek word ιδιωτης, idiôtês, "a private citizen, individual", from ιδιος, idios, "private". In ancient Athens, an idiot was a person who declined to take part in public life, such as democratic city government. Since such activities were honorable and could directly affect all citizens, idiot was a term of derision.

• Imbecility was a type of mental deficiency less extreme than idiocy and not necessarily inherited. It is now usually subdivided into two categories, known as severe mental retardation and moderate mental retardation.

• Moron was defined by the American Association for the Study of the Feeble-Minded in 1910, following work by Henry H. Goddard, as the term for an adult with a mental age between eight and twelve; mild mental retardation is now the more widely-accepted term for this condition. Alternative definitions of these terms based on IQ were also used. For example, the following data based on the Wechsler adult IQ test (WAIS) were used in 1958:

Class	IQ
Conway	1
Idiot	below 20
Imbecile	20-49
Moron	50-69
Borderline deficiency	70-79

Today the following ranges are in standard use:

Class	IQ
Profound mental retardation	below 20
Severe mental retardation	20-34
Moderate mental retardation	35-49
Mild mental retardation	50-69
Borderline deficiency	70-79

In other Westen nations, such as Australia, New Zealand and Great Britain, the term Mental Retardation is now considered Politically incorrect. The term Intellectual Disability is currently favoured.

References

• Wechsler, David The Measurement of Adult Intelligence (1944), Baltimore, The Williams & Wilkins Company.