Intellectual Disability

Previously known as mental retardation
Intellectual Disability

What is intellectual disability?


Anirudh is four years old but cannot walk independently. Though he recognizes some friends and members of his family, he can’t seem to name the parts of his face and can't say any meaningful words. He was diagnosed with intellectual disability (mental retardation) and is said to have the mental abilities of a one-year-old.

This fictional narrative has been constructed to aid the understanding of this disorder by placing it in a real-life situation.

Intellectual disability, once called mental retardation is a condition in which there is a delay in all aspects of development. The delay is found in four areas of development, namely, motor skills (control over body movements), cognitive ability (to think, understand and deal intelligently with situations), social skills (interacting with people and learning appropriate social behavior) and language functions (understanding what others say and learning to talk). Intellectual disability is also referred to as mental deficiency, mental sub-normality and intellectual deficiency.

Note: The term mentally retarded, though widely used in India, is considered derogatory. This section will use the term intellectual disability to refer to the disorder.

Intellectual disability is not a mental illness. Rather, it is a condition in which there is a delay in mental development and is always present from childhood.

After birth, human beings continue to develop physically and mentally until they are eighteen years of age, in what is called the developmental period. Mental development occurs in a sequential and orderly manner. For example, most babies can say a few words by the time they are around fifteen months old. When babies fail to acquire these milestones, or there is a significant shortfall in the development or mental abilities, or when a child scores in a range less than 85 in a standardized Intelligence Quotient (IQ) test, then the child is said to be suffering from intellectual disability.


What are the signs of intellectual disability?


Some medical conditions associated with intellectual disability can be detected at birth itself. Premature babies, those with low birth-weight and babies who have suffered asphyxia at birth are likely to be at higher risk of developing intellectual disability. Babies with severe intellectual disability can be recognized by the age of 6-12 months. Mild cases become evident by the age of two years. Most people with intellectual disability have the condition from birth. However, damage to the brain in later childhood can also cause intellectual disability.

Children with intellectual disability may learn to sit up, crawl, or walk, or talk much later than other children. Both adults and children with intellectual disability may also exhibit some or all of the following characteristics.

  • Delay in reaching developmental milestones

  • Delay in language development

  • Deficit in memory skills

  • Difficulty learning social rules

  • Difficulty with problem solving skills

  • Delay in the development of adaptive behaviors such as self-help or self-care skills

  • Lack of social inhibitors


When you should be alert?

  • If the child is born prematurely with a birth-weight less than two kgs

  • If there are repeated convulsions in early infancy

  • If the baby is inactive or very lethargic

  • If the child is dependent for self-care activities such as eating, dressing and toilet control even at the age of 4-5 years

  • If the child is slow in reaching developmental milestones


What are the common health problems associated with intellectual disability?


Most children with intellectual disability are otherwise physically and mentally healthy; except that they have lower intelligence than others. However, some health problems are associated with the disorder.

Behavioral problems: A person with intellectual disability can display high levels of restlessness, impulsiveness and can be irritable and throw temper tantrums. These qualities sometimes manifest as aggressive and self-injurious behavior. Dealing with an aggressive person can cause great stress to caregivers. It is advisable to consult a mental health expert on how to placate an aggressive child.

Convulsions: Convulsions are a fairly common occurrence in a person with intellectual disabilities. The convulsions may involve the whole body, parts of the body or just be single jerks that cause the person to lose balance and fall down. Convulsions can be easily controlled with the help of medication.

Sensory impairments: Around 10 percent of people with intellectual disability have trouble with seeing and hearing. These problems can be resolved with the help of hearing aids, spectacles or corrective eye surgery.

Note: Other developmental disabilities such as cerebral palsy, speech problems, and autism can co-exist with intellectual disabilities.

What causes intellectual disability?


There are several different causes for intellectual disability. The list below is only indicative.

Causes before birth or prenatal causes

  • Chromosomal disorders such as Down syndrome, Fragile X syndrome, Prader Wili syndrome, Klinefelters syndrome

  • Single gene disorders

  • Conditions of genetic origin such as RubisteinTabi syndrome and De Lange syndrome

  • Maternal or environmental influences

  • Deficiencies of nutrients such as iodine and folic acid

  • Severe malnutrition during pregnancy

  • Use of substances such as alcohol, nicotine, and cocaine during pregnancy

  • Exposure to harmful chemicals, heavy metals and medication during pregnancy

  • Maternal infections such as rubella, syphilis and HIV

Causes at the time of birth or perinatal causes

In the third trimester

  • Placental dysfunction

  • Heart or kidney complications in mother

During labour or delivery

  • Premature birth

  • Very low birth-weight

  • Birth asphyxia

  • Birth trauma

Within four weeks after birth or neonatal causes

  • Jaundice

  • Hypoglycemia

  • Septicemia

In infancy and childhood

  • Brain infections such as tuberculosis or bacterial meningitis

  • Chronic lead exposure

  • Severe and prolonged malnutrition

  • Head injury


What is the treatment for intellectual disability?


Intellectual disability cannot be cured, but with the right kind of support and services, it can be ensured that the person with intellectual disability can live healthy and relatively independent lives. Experts point out that ill health and behavioral issues among those with intellectual disability is often a result of inadequate care and can therefore be prevented.



How to care for someone with intellectual disability?


Intellectual disability is a life-long condition. Caring for a person with intellectual disability can be stressful and requires patience. The good news is that there are several resources and support groups that help caregivers cope and ensure that their loved one with this disability can live a healthy and relatively independent life.

Normalization is a concept that originated in the Scandinavian countries; it makes available, the environmental conditions for everyday life to people with intellectual disability, as much as they are available to anybody else. It is the right of people with intellectual disability to lead their lives with respect and dignity. It is important that they be integrated into society and not be discriminated against.

Families with members suffering from intellectual disability tend to face a lot of stress during caregiving. The stress may be a result of stigma faced among friends and family, and in the community, the pressure of daily care and support, lack of personal time and financial implications. Caregivers need to set aside time to care for themselves, be better informed about their ward’s condition and also talk to other caregivers about the measures they are taking to normalize the environment around their wards.

Tips for caregivers

  • Seek information and clarify all doubts from experts

  • Talk to other caregivers for support

  • Concentrate on the abilities rather than the disabilities of your child

  • Learn techniques of training from special educators and practice these methods

  • Don’t be ashamed of your ward and clarify the misconceptions of friends and family who don’t understand the condition

  • Though people with intellectual disability are slow in their learning, when taught with patience and persistence they can be taught several skills and even learn to be self-sufficient to a certain extent

  • Do not overprotect your child

  • Avoid looking for non-scientific cures for intellectual disability—there are none


There are many claims that some drugs or herbal preparations can improve intelligence. These claims are entirely false. Intellectual disability cannot be cured. However, it is important to seek medical help to evaluate the extent of the disability and psychologically assess the strengths and weaknesses of the child. This assessment will form the basis for future educational, life-skill and vocational training of the child.

Early intervention

Research shows that when intellectual disability is detected at an early stage and when the child is provided with a stimulating, secure and loving environment, the child tends to develop better. Babies who are at risk or have already been detected with delays in development should actively receive sensory-motor stimulation. These include methods through which the parent encourages the baby to develop sensory (vision, hearing and touch) and motor (grasping, reaching, manipulating and transferring) faculties.


As children with intellectual disabilities learn to conduct their daily lives it is also important for them to learn academic skills, discipline and social skills. It is encouraged that children with mild intellectual disability attend mainstream schools rather than special schools. However, children with severe disability may benefit from special schools where the curriculum is specially designed for them. Whichever school a parent chooses, it is most important that the child is given an educational experience.

Vocational training

People with intellectual disability can be trained vocationally and be employed. It is quite common to underestimate their capability.


Can intellectual disability be prevented?


The prevention of intellectual disability refers to measures that reduce the risk of developmental issues in the community. A large number of these practices are related to maternal and child healthcare.

Some steps include:

  • Improving the nutritional status of the community to reduce causes such as low birth-weight

  • Iodization of salt to prevent deficiency

  • Administration of folic acid tablets to reduce neural tube defects

  • Nutritional supplements including intake of iron and calories

  • Immunization of children to prevent disorders that may damage the brain

  • Avoiding pregnancy before the age of 21, which increases the chance of complications in labor. Also avoiding pregnancy after 35, when the chance of chromosomal disorders such as Down syndrome increases.

  • Spacing pregnancies to help the mother replenish herself nutritionally

  • Avoiding exposure to harmful chemicals and substances like alcohol, nicotine and cocaine during pregnancy

  • Screening pregnant women for infections such as syphilis

  • Preventing Rh iso-immunization which can arise when the mother has Rh negative blood. Damage to the fetus can be prevented by administering anti-D immunoglobin after the first delivery

  • Treatment of severe diarrhea and brain infection during childhood

This section been compiled after referring to a document created for the World Health Organization (WHO) on the subject of mental retardation. The original document has been authored by Dr Satish Girimaji, NIMHANS, Bangalore, Dr Sultana S Zaman from Bangladesh Protobondi Foundation, P M Wijetunga from Susita Suwasetha Parents Asscociation Sarvodaya, Sri Lanka and Dr Udom Pejarasangharn, Rajanukal Hospital, Bangkok.

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