Intellectual disability (also called mental retardation)
is often poorly understood because its effects vary greatly among those who have it. Many people with intellectual disability are mildly affected. They are only a little slower than average in learning new information and skills. As children, their intellectual disability is not readily apparent and may not be identified until they enter school. As adults, many are able to lead somewhat independent lives.
People with intellectual disability who have a very low intelligence quotient (IQ) have serious limitations in their ability to function. However, with early intervention and appropriate support, they can also lead satisfying lives.
What Is an Intellectual Disability?
Intellectual disability begins in childhood and is characterized by limitations in both intelligence and adaptive skills. The following three criteria must be met for a diagnosis of intellectual disability:
IQ below 70
Significant limitations exist in two or more adaptive skill areas. These include:
Any condition that impairs development of the brain before birth, during birth, or during childhood can cause intellectual disability. The main causes can be categorized as follows:
Genetic abnormalities may be inherited from parents or may be caused by environmental factors.
More than 500 genetic diseases are associated with intellectual disability. Examples include:
—Children born with this rare genetic disorder cannot metabolize phenylalanine (PHE), which is an amino acid found in food. Without proper treatment, PKU can lead to intellectual disability.
Down syndrome—In a normal fertilized egg, chromosomes exist in pairs. But, in the case of Down syndrome, there are three of chromosome 21.
Fragile X syndrome—This is caused by mutations of the FMR1 gene, the leading cause of inherited intellectual disability.
Problems During Pregnancy
by a pregnant mother can cause intellectual disability.
can increase the risk, as well. Other risks during pregnancy include:
Certain environmental toxins
Illnesses of a mother during pregnancy that can be passed on to her infant, such as:
and low birth weight may sometimes lead to intellectual disability. These conditions may be associated with bleeding in or around the brain. However, other birth conditions or physical stress in the newborn stage may injure an infant's brain.
Problems After Birth
Other conditions that can damage a child's brain and possibly lead to intellectual disability include:
or meningitis, especially in the newborn stage
Children in poor families may become mentally retarded because of:
Inadequate medical care
Environmental health hazards
Lack of stimulation to help the brain grow
How Is an Intellectual Disability Diagnosed?
The American Association on Intellectual and Developmental Disabilities (AAIDD) has a process for diagnosing and classifying a person with intellectual disability. This process involves assessing the person's IQ and adaptive skills. Adaptive skills fall into three categories:
Conceptual skills—For example, can the person read and write? Does he understand concepts like time and money?
Social skills—Does the person follow rules? Does he have interpersonal skills? Can he solve social problems?
Practical skills—Can the person take care of his daily needs? Can he work, use money, and keep himself safe?
What Are the Treatment Options?
The best assistance for people with intellectual disability begins with diagnosis and help early in life. Treatment includes:
Training in daily living skills
With enough education and support, many people with intellectual disability can learn to take care of their basic needs and to live in the community.
Can Intellectual Disabilities Be Prevented?
Newborn screening followed by proper treatment can prevent intellectual disability resulting from certain conditions. Examples include:
Vaccines can prevent certain infectious diseases that may lead to intellectual disability, such as:
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a