Intellectual disability

Children with disabilities competing at the Special Olympics, in Okinawa

Intellectual disabilityis a condition of the brain. People suffering from it are not assmartas the average person of their age group; because of this, they often have trouble with getting through daily life, without the help of others. The condition is also known asintellectual developmental disability,orgeneral learning disability.It used to be calledmental retardationbut that term is not used very much any more.It is classified as alearning disability.Intellectual disability becomes apparent inchildhood.There are a number of conditions that show as intelectual disability.

There are two main forms: In one form, the disability occurs together with other healh issues (or syndromes), in the other it occurs on its own.

Signs and symptoms

Aweightlifterwith down syndrome

To have an intellectual disability, a person must:

• Have anintelligence quotient(IQ) score of less than 70 (this is just over two people in a hundred) and
• Have trouble with parts of daily life.

Types of intellectual disabilities

There are two major types of intellectual disability.

The first issyndromic intellectual disability.This means that the person has asyndromethat causes intellectual disability, as well as medical issues and other problems.Down syndromeandfetal alcohol syndromeare two examples of syndromic intellectual disabilities.

The second isnon-syndromic intellectual disability.This means that the intellectual disability is not a part of a syndrome.

Levels of intellectual disability

There are three levels of intellectual disability, based on how severe a person's disability is:

• The first and most common ismild intellectual disability.A person with mild intellectual disability can usually act without help from other people, but may need help with things like paying taxes.
• The second level is moderate intellectual disability. Someone with moderate intellectual disability has an IQ between 40 and 55. They cannot live by themselves, but can learn to perform basic tasks.
• The third level is severe intellectual disability. Someone with severe intellectual disability needs a lot of help and can only do simple things.

Mild intellectual disability may not be noticed until a child starts school. Moderate and severe intellectual disability can be seen before a child starts school.

Epidemiology

Intellectual disability affects about 2 to 3% of the general population.Seventy-five to ninety percent of the affected people have mild intellectual disability.Non-syndromic, or idiopathic cases account for 30 to 50% of these cases.About a quarter of cases are caused by agenetic disorder,and about 5% of cases areinherited.Cases of unknown cause affect about 95 million people as of 2013. The top three most common causes of intellectual disability aredown syndrome,DiGeorge syndrome,andFetal alcohol syndrome.

Genetic disorders

Genetic disordersare caused by problems with a child'sgenes.Children areborn with these disorders.

• For example, down syndrome happens when a child has an extra copy ofchromosome21. Another example isDiGeorge syndrome.This is caused by the deletion of a small segment of chromosome 22.

Problems during pregnancy

Substances calledteratogenscan prevent afetusfrom developing normally. If a teratogen enters a woman's body while she ispregnant,it can cause developmental problems, like intellectual disabilities.

Examples of teratogens that can cause intellectual disabilities include:

• Alcohol
  • Alcohol is the most common cause of intellectual disability which can be prevented. Alcohol ispoisonousto a fetus and can cause fetal alcohol syndrome if a mother drinks while pregnant
• Illegal drugs
• Certain medications, likewarfarin(a blood-thinning medicine) andthalidomide
• Certaintoxicchemicals,likeleadandmercury,if a woman is exposed to enough of them during her pregnancy
• Certain diseases, likerubellaandsyphilis,if the mother has them during pregnancy

Problems during birth

For example, if a child does not get enough oxygen during birth, it can hurt the brain and lead to intellectual disability later.

Diseases and trauma

Some childhood illnesses, likemeaslesandwhooping cough,can cause intellectual disability if not treated properly. So caninfectionsthat affect the brain, likemeningitisandviralencephalitis.

Brain injuriescan cause intellectual disability at any age.

Malnutrition

Lack of proper nutritioncan lead to intellectual disability over time.

Iodine deficiency

Iodinedeficiency (not having enoughiodinein the body) can lead to several medical issues, including intellectual disability. The most common way to prevent this is by addingiodine to salt.This is a much more common problem indeveloping countries.

Diagnosis

A boy uses a swing duringoccupational therapy.

In theDSM,there are three requirements a person has to meet in order to be diagnosed with an intellectual disability.

Low intelligence quotient (IQ)

First, the person must have a lowintelligence quotient(IQ). IQ is measured with anIQ test.

If the person has an IQ of below 70, theymayhave an intellectual disability. However, they must still meet the other two requirements to be diagnosed with an intellectual disability.

Trouble with daily activities

Second, to qualify for an intellectual disability, a person must have trouble in more than one area of normal daily activities. These activities are often called "adaptive behaviors" or "activities of daily living (ADLs)." Some examples of adaptive behavior are:

• Getting dressed
• Using the bathroom
• Eating and drinking
• Being able to have a conversation
• Acting properly in different situations

To see if a child is having trouble with these, a doctor will talk to people who know the child, and will watch the child's behavior.

Beginning in childhood

The final requirement is that the symptoms of intellectual disability have to begin in childhood oradolescence.If the issues do not start at a young age, they are probably caused by a different illness of the brain.

Management

There is currently no cure for intellectual disability. Those affected can learn to cope and do many things, if they get enough support and are taught well. There are many places around the world for someone with intellectual disability to get help. These places, such asgroup homes,can take care of people with intellectual disabilities, as well as help them find jobs, find a house of their own, or help them take care of their children.

There are some different ways for people with intellectual disability and those around them to learn how to help the person with the disability.One kind is psychosocial treatment. This is meant for very young children. Psychosocial treatment helps them learn basic skills and increase learning over their lifetime. Another kind isbehavioraltreatment. This is meant to help young people, but can be used for adults as well. Behavior treatment helps teach language skills as well as social skills like sharing or following instructions. A third kind of help iscognitive-behavioral treatment.This is a combination of the previous two treatments. Cognitive-behavioral therapy helps children with intellectual disability both learn skills and learn how to plan ahead. Another type of help a person with intellectual disability can get is family-oriented help. Family-oriented help focuses on teaching family members how to help the person in their family with intellectual disability.

Many people with an intellectual disability have other health problems, for which they will be given specific drugs. As an example,autisticchildren with developmental delay may useanti-psychoticsormood stabilizersto help with behavior. Giving drugs to intellectually disabled people needs to be monitored; side-effects often occur, and are wrongly diagnosed as problems with behavior or aspsychiatricproblems.

History

A boy with down syndrome gets his picture taken.

People have had intellectual disability throughout history. People with intellectual disability have had a lot of trouble in the past. The oldest idea of where intellectual disability came from was in ancient Greece.Hippocratesthought that intellectual disability was caused by an issue with thefour humors.For several hundred years in Europe, churches took care of people with intellectual disabilities. In the 17th century, Thomas Willis suggested that intellectual disability was adiseasecaused by issues with the structure of thebrain.In the 18th and 19th centuries, people with intellectual disabilities were put inasylums.The asylums would give them basics like food and shelter, but were not always good to the people in them. In the early 20th century, people with intellectual disability were made to not be able to have children and could not marry. It was thought that this would reduce the amount of intellectual disabilities in the future.This is not done anymore because it does not follow the idea ofhuman rights.

In the 1950s, a group called the Civitans started to help people with intellectual disability. In the '70s, many people wanted to remove thestigmaaround people with intellectual disability. Now, people with intellectual disability are treated as people with something to be fixed instead of less than “normal” people. There are also fewer people with intellectual disability being sent to asylums.

Words that were used to describe people with an intellectual disability have changed a lot. The most common words used today are “special”, “challenged”, "learning disabled" and “developmentally delayed”. Some previous words to describe people with intellectual disability are “cretin”, “idiot”, “imbecile”, “moron”, and “retarded”, all of which are now regarded as insulting.

Society

People with intellectual disability are often treated badly by people without disabilities. They are often not allowed to make choices about their own lives and are not considered a full part of society. Their abusers are often people who are supposed to care for them. 39-83% of women with intellectual disability will be sexually abused before they are 18 years old.

Thedignityandhuman rightsof people with intellectual disability are protected by theConvention on the Rights of Persons with Disabilitiesas well as otherdisabilitiesand equally like other persons without disabilities.