Intellectual Disability (ID) In Children: Signs, Causes & Treatment

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Intellectual disability (ID) is a condition wherein a child has significantly below-average intellectual functioning that limits the ability to perform routine daily activities (adaptive skills). An intelligence quotient (IQ) below 70 is considered a diagnostic criterion of intellectual disability, which may present itself from birth or early infancy (1). Formerly called mental retardation, it is now termed intellectual disability to avoid social stigma.

Intellectual disability is a neurodevelopmental disorder due to the brain’s growth and developmental problems, but it is not a mental health disorder. Proper prenatal care may reduce the risk of intellectual disability, and early special education and medical care could help children learn adaptive skills.

Read this post to know about the causes, types, symptoms, diagnosis, treatment, and prevention of intellectual disability in children and tips for parents and teachers to manage children with intellectual disabilities.

How Common Are Intellectual Disabilities?

About 1-3% of the world population or nearly 200 million people have intellectual disability. The US alone has 6.5 million people with intellectual disabilities (2).

It is more common in low-income countries affecting 16.41 in every 1000 people. According to the United Nations Development Program’s estimation, 80% of people with disabilities belong to low-income countries (2).

Symptoms Of Intellectual Disability In Children

In most children, symptoms and signs of intellectual disability may not be noticeable until preschool age. Children with a severe form of disability may have early onset of symptoms. However, the exact diagnosis is made after formal testing.

The following symptoms and signs are often associated with intellectual disability in children (3).

  • Unusual facial features
  • Macrocephaly (too large head)
  • Microcephaly (too small head)
  • Hands and feet malformations

Some children may not have any physical features but may show signs and symptoms of serious problems (3).

  • Seizures
  • Failure to thrive
  • Drooling
  • Protruded tongue
  • Lethargy
  • Developmental delay
  • Vomiting

The following behavioral signs and symptoms are often seen in children with intellectual disability (4).

  • Slow responses
  • Inability to make decisions
  • Aggressive reactions when demands are denied or fulfilled with delay
  • Memory problems
  • Difficulty solving problems
  • Poor or lack of attention
  • Difficulty in social interaction

Children with severe intellectual disabilities may have difficulties learning early motor skills such as rolling, sitting up, or standing in the first year of life. Language development delay is the most common issue faced by children with intellectual disabilities, and it is often discovered in the preschool age.

Children may not be able to speak complete sentences due to language difficulties and cognitive impairment. Temper tantrums, aggressive or self-harming behaviors, explosive outbursts, etc., are more common in children with ID than in a normal child. These behavioral problems can often be due to frustrations from impaired communication skills or motor skills.

Causes Of Intellectual Disability In Children

Various medical, environmental, and genetic factors during pregnancy, birth, or after birth may cause intellectual disability in children. These factors may result in damage or often interfere with the development of the brain. Specific causes of intellectual disability are not always identified.

The following genetic factors, such as inherited disorders and chromosomal abnormalities, may increase the risk of intellectual disability (3).

  • Down syndrome
  • Fragile X syndrome
  • Phenylketonuria (PKU)
  • Tay-Sachs disease
  • Neurofibromatosis
  • Congenital hypothyroidism

The following maternal complications or situations during pregnancy may increase the risk of ID in children (5).

  • Undernutrition
  • Alcohol use
  • Exposure to toxins, such as methylmercury and lead
  • Preeclampsia
  • Multiple births such as having twins or triplets
  • Exposure to certain drugs, such as chemotherapy drugs, valproate, phenytoin, etc.
  • Infections with Zika virus, rubella, cytomegalovirus, toxoplasma gondii, herpes simplex virus, or HIV

The following factors may increase the risk of ID during birth (5).

  • Fetal hypoxia or insufficient oxygen for long periods during the birth
  • Extreme premature birth

The following factors may cause ID after birth (5).

  • Meningitis
  • Encephalitis
  • Severe head injury
  • Near drowning (drowning accident)
  • Undernutrition
  • Emotional abuse or neglect
  • Lead or mercury poisoning
  • Brain tumors
  • Chemotherapies

Diagnosis Of Intellectual Disability In Children

There are various tests to assess intellectual disability and also to predict the risk of developing it. These include (6):

  • Prenatal screening, such as amniocentesis or chorionic villus sampling, is useful for identifying genetic disorders, such as Down syndrome.
  • Growth and developmental screening could help assess developmental delays during infancy.
  • Imaging tests such as MRI may help to identify brain abnormalities.
  • An electroencephalogram is done to assess the electrical activity of the brain if seizures are present.
  • Genetic testing can be useful to identify inherited disorders.
  • Laboratory tests such as blood tests and urine tests are done to identify infections and toxins or confirm specific inherited disorders.
  • The hearing evaluation is often done to exclude the diagnosis of hearing impairment in children with language difficulties.
  • Formal intellectual and skills testing is done to assess the mental functioning of the child. These tests include a parental interview, observations, and comparison of scores with the same age children. A score below 70-75 is required to diagnose ID. Stanford-Binet intelligence test and Wechsler intelligence scale for children aim to measure intellectual functioning. In contrast, tests such as Vineland adaptive behavior scales are done to assess communication, social abilities, and motor skills.

Doctors consider multiple factors before diagnosing intellectual disability, and tests are often ordered based on the possible causes. It is crucial to diagnose the problem and identify the cause to plan an early intervention to improve a child’s functioning level.

Adaptive Skills And Support

The degree of impairment can be different in each child, varying from mild to severe disabilities. It is measured by the scores of standardized intelligence tests. But the impact of the impairment is assessed based on the support a person requires to perform adaptive skills. That means a child with mild intellectual disability may have poor adaptive skills, thus requiring extensive support.

According to scores of IQ tests, about 3% of the population scores less than 70, which means they meet the criteria for the diagnosis of intellectual disability. However, only 1% of the population has a severe intellectual disability that requires support (7).

Adaptive skills are everyday skills to meet the demands of one’s environment. These may include (7):

  • Self-care skills, such as bathing, feeding, dressing, etc.
  • Social skills, such as interpersonal relationships, obeying rules and regulations.
  • Functional academics, such as reading, writing.
  • Leisure skills include taking responsibility for activities and participating in the community.
  • Ability to adapt to home or school environment and ability to work independently to meet work standards.
  • Ability to use transport, perform shopping, etc.
  • Health and safety awareness such as a measure to protect oneself from danger and respond to health issues.

The support required for the intellectually disabled is categorized as (7):

  • Intermittent: Requires occasional support
  • Limited: May require support for some activities
  • Extensive: Ongoing daily support is required
  • Pervasive: Need support for all activities, often require nursing care

Children may lack skills and may require constant support or assistance. However, a few children may gradually learn skills with proper training and manage their day-to-day life.

Treatment For Intellectual Disability In Children

Management aims to improve the child’s intellectual functioning levels and train them in adaptive skills. Multidisciplinary support is required to care for a child with intellectual disability. It may require the support of the following specialists (6).

  • Primary care doctor or pediatrician
  • Social worker
  • Speech pathologists or therapist
  • Physical therapist
  • Occupational therapist
  • Neurologist
  • Psychologist
  • Nutritionist
  • Behavior consultant/therapist

The involvement of the family is an essential factor in individualized programs for the child. Home is the best living place for children with intellectual disabilities. However, children with complex disabilities and behavioral problems, such as harming others or self or those with severe physical disabilities, may be moved to specialized centers based on parents’ willingness and care teams’ opinions.

How To Help A Child With Intellectual Disabilities?

Encouragement and support from parents and teachers are essential to improve the child’s intellectual functioning. Although living with an intellectual disability can be challenging, it is possible to learn skills and adapt to it over time.

Tips for parents

The following measures may help parents understand and support the child (8).

  • Learn about intellectual disability
  • Be patient while the child learns and grows
  • Encourage the child to be independent, despite it being difficult or time-taking for them to learn adaptive skills such as feeding, grooming, dressing, or using bathrooms
  • You may involve them in age-appropriate household chores and errands
  • Give positive feedback when the child does things well or tries their best
  • Find opportunities for them to interact and socialize with others
  • Get support from support groups
  • Be in touch with the child’s teachers
  • Encourage the child to learn what they love, such as painting, dancing, singing, etc.

Tips for teachers

Education must be least restrictive and in the most inclusive setting, such as with occasions to interact with non-disabled peers (9).

The following tips can help teachers bring out the best in intellectually disabled students (9).

  • Learn about the condition
  • Recognize the enormous difference that a teacher can make to the life of a student with intellectual disabilities
  • Teach new tasks in smaller segments
  • Teach using visuals or videos; these can be referred back to when things are forgotten
  • Try to explain with demonstrations than verbal directions
  • Always give immediate feedback
  • Teach daily living and social skills, such as how to greet someone, how to count money, occupational exposures, and opportunities, etc.
  • Keep in touch with parents

Prevention Of Intellectual Disability In Children

The following measures may help to prevent the risk of developing intellectual disability in children (1).

  • Proper prenatal care may lower the risk of IDs, such as taking folate vitamin supplements, reduces the risk of neural tube defects and premature birth
  • Maintain adequate nutrition intakes during pregnancy
  • Prenatal screening
  • Avoid alcohol use during pregnancy
  • Get vaccinations against rubella
  • Seek prescription to use drugs before conception and pregnancy since some medication may affect fetal growth and development
  • Proper neonatal care and nutrition may reduce after-birth risk factors for ID
  • Always seek medical attention for symptoms of toxicity or infections in neonate before it complicates

In some circumstances, parents may receive counseling to prevent the risk of having another child with intellectual disorders, primarily if it is caused by inherited disorders.

About 35.4% of intellectually disabled people also have mental health disorders such as anxiety and depression (10). Mistreatments and bullying from peers and people around them is the primary cause of these mental health issues. Special Olympics games are one of the great movements that helped many physically and intellectually challenged people discover their abilities, feel confident about themselves, and educate society about these conditions.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Intellectual disability; MedlinePlus; The United States National Library of Medicine
2. What is Intellectual Disability?; Special Olympics
3. Module on Training of Resource Teachers under SSA on Mental Retardation; Sarva Shiksha Abhiyan; The Government of India
4. Intellectual Disability; The American Speech-Language-Hearing Association (ASHA)
5. Intellectual Disability; Winchester Hospital; Beth Israel Lahey Health
6. Intellectual Disability; MSD Manual
7. Adaptive Skills: Skills for Everyday Life; The American Exceptional Students Association (AESA)
8. What is Intellectual Disability?; The American Psychiatric Association
9. Intellectual Disability;; center for Parent Information and Resources
10. Factors associated with depression and anxiety in children with intellectual disabilities; ; Wiley Online Library

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