Everything You Need To Know About Intellectual Disability

Have you felt that your child, is not like other children? Like they are a little slower in understanding or learning things as compared to other children? Some children have brains that have not developed appropriately, or have some sort of damage. In earlier times, this condition was known as mental retardation, but it is called intellectual disability today, and it’s a lifelong condition.


An individual is said to have an intellectual disability when they lack generic mental abilities, which have an adverse effect on:

  • Reasoning, learning, academic skills, solving problems, abstract thought, judgement, memory, and such intellectual functioning
  • Ability to care independently for oneself, including performing routine tasks at home or school/work, money management, personal care – practical functioning
  • Ability to conduct oneself normally and confidently in society by using skills like communication, social judgement, appreciating the after-effects of one’s acts, making friends, comprehending and following social clues and rules, and other aspects of social functioning.

There are four levels of ID – mild, moderate, severe, profound, and in some cases, the classification could be ‘other’ or ‘unspecified’.

It is manifested by both a low IQ, and problems with everyday activities, learning, social, physical, and speech disabilities.

Usually, severe cases can be diagnosed almost immediately after birth; but in milder cases, you may only realize it when your child is unable to meet normal development goals. Whatever the severity level, a diagnosis is reached by the time the child touches 18 years of age.

Symptoms of Intellectual Disability

Symptoms vary from individual to individual and depend on several factors, especially the disability level. Some common symptoms:

  • Inability to meet intellectual milestones
  • Unable to sit, crawl, walk etc. as per normal milestones
  • Unable to talk or speak clearly
  • Poor memory
  • Not understanding that their actions have consequences
  • No logic in thinking
  • Childish behaviour, often inconsistent with age
  • IQ less than 70
  • Struggling to learn
  • Not able to live independently because of the inability of self-care, social interaction and communication challenges
  • Behavioural issues like aggression, dependence, attention-seeking, depression, socially inactive, impulsive behaviour, stubbornness, inability to focus, quick frustration, psychotic problems, poor self-esteem and tendency to self-harm
  • Abnormal facial features, short stature, and other abnormal physical characteristics

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Symptoms According to Levels of Intellectual Disability

We have seen above that there are four levels of ID – this is based on the individual’s IQ, and how well or not they adjust socially.

Mild intellectual disability

  • Slow to learn how to talk, but capable of communicating well once they learn
  • Gaining full independence in taking care of themselves when older
  • Inadequate reading and writing skills
  • Social awkwardness and immaturity
  • Unable to handle family life
  • IQ range from 50 to 69
  • Can improve with specialized education programs

Moderate intellectual disability

  • Poor language abilities
  • Communication difficulties
  • ID level from 35 to 49
  • Able to learn basic reading, writing and arithmetic
  • Unable to lead independent lives
  • Can commute independently to familiar, everyday places
  • Able to participate in different social activities

Severe intellectual disability

  • Poor motor skills
  • Severe damage to the central nervous system, or improper development
  • IQ of 20 to 34

Profound intellectual disability

  • Unable to follow instructions or requests
  • Poor mobility
  • Nonverbal or minimal communication
  • Unable to care for themselves without help
  • Incontinence
  • IQ under 20
  • Constant need of help and supervision

Other intellectual disability

Individuals diagnosed as having ‘other’ ID usually have a physical impairment, are nonverbal, have poor or no hearing, or have physical disabilities; this may not allow the doctor to perform diagnostic tests.

Unspecified intellectual disability

Some individuals may exhibit intellectual disability symptoms, but there isn’t enough information for the doctor to categorize the level of disability.

What causes intellectual disability?

Intellectual disability can be caused by any number of factors, but often the exact cause is not known; injury, disease, a problem in the brain – anything, or none of these, could cause ID. Down Syndrome, Fragile X Syndrome, infections, birth defects, Fetal Alcohol Syndrome and so on, can happen before birth, whereas some may happen during birth, or immediately after. Sometimes, causes of ID occur when the child is older – this includes stroke, infections like meningitis, head injuries, etc.

Genetic conditions

ID is sometimes caused because a child inherits abnormal genes from parents, or due to some errors that happen when certain genes combine, and so on. PKU or phenylketonuria, Fragile X syndrome, Rett Syndrome, Prader-Willi Syndrome, and Down syndrome are examples.

Pregnancy Complications

If a baby does not develop inside the mother’s womb properly, it may result in an intellectual disability. This could be due to some abnormalities in the cell division of the fetus, the mother contracting rubella or some other dangerous infection, or because she consumes alcohol, tobacco, etc.

Birth Complications

In some deliveries, the baby gets insufficient oxygen, is born prematurely, or the labour may be long and complicated. This can also result in the child having an intellectual disability.

Diseases or Toxic Exposure

Measles, meningitis, whooping cough and certain other diseases can cause ID in babies or young children. The absence of medical care, malnutrition, and exposure to mercury lead, drugs like meth, and other toxins can also lead to ID.

Intellectual disability is not a mental illness, like severe anxiety or depression, and there is no cure for it. But, children with ID can be equipped to overcome many of their challenges with the right approach and guidance.

How Common Are Intellectual Disabilities?

Globally, about 1-3% of the population has an intellectual disability; this is roughly 200 million people. It is found more commonly in low-income countries; people with disabilities, as per the UN, represent one in 10 people, with one in five being among the poorest in the world. In Australia, about 450,000 people have IDs. About 4.5% of Australian children have intellectual disability, and it’s twice as common among boys as in girls.

How is Intellectual Disability Diagnosed?

If your child has a low IQ and adaptive and intellectual skills that are lower than the accepted average, your child could be diagnosed with ID. The doctor usually performs an evaluation in three phases – interviews with parents, observing the child, standard tests of IQ and behaviour, like the Vineland Adaptive Behavior Scales or similar. This will help the doctor to evaluate the daily living and social abilities of your child, in comparison with other children of his or her age. You should note that children from diverse backgrounds and social strata may perform differently on this test, so this will not be the only factor used for diagnosis. Your interviews, the observations of the child’s behaviour, etc., will be used in combination to arrive at a diagnosis.

Your child may be evaluated by the following professionals:

  • Developmental paediatrician
  • Pediatric neurologist
  • Psychologist
  • Social worker
  • Speech therapist
  • Physical therapist

The doctor is likely to order diagnostic tests that help the doctor to determine if there are any genetic or metabolic disorders or structural problems with the child’s brain.

Delayed development can also be caused by learning and neurological disorders, emotional issues, hearing loss, and so on; the doctor should ideally check for these conditions before the final diagnosis.

You, the doctor, and the child’s school can use the test results and assessments to craft a treatment and education plan for your child.

Intellectual Functioning

This is measured with comprehensive, standardized tests that are psychometrically sound and culturally appropriate. A full-scale IQ test is not necessary for diagnosis anymore, but it is still used to aid in diagnosis. It should be remembered that the IQ score has to be interpreted with reference to the individual’s problems in generic mental abilities. Sub-test scores may show marked variance, so the IQ score may not reflect accurate overall intellectual functioning; clinical judgement is, therefore, a very important aspect of interpreting IQ test results.

Adaptive Functioning

Doctors check the following:

  • Social abilities of judgement, ability to follow instructions and rules and make friendships, having empathy, and communication ability
  • The conceptual ability of learning language, math, reading and writing; logic, memory, and knowledge
  • Practical abilities like being independent and capable of self-care, managing job and family responsibilities, being organized in performing tasks, participating in recreational activities.

Interviews with the child, parents, other family members, teachers, and caregivers if any, and standard techniques are employed to assess the adaptive functioning of the child.

Treatment Options for Intellectual Disability

Usually, children with intellectual disabilities need continuous counselling and therapy to help them manage their disabilities. You can get a detailed family service plan that defines your child’s needs, and the services the child requires to help them develop normally, along with your family needs.

Early and continuous intervention is key to helping your child cope with their disability and help them reach their maximum potential in social and life skills, and education. Treatment may include counselling, medication in some instances, behavioural and occupational therapy, and so on. The following professionals may work with your child:

  • GP
  • Genetic counsellor
  • Child and family health nurse
  • Paediatrician
  • Social worker
  • Psychologist
  • Occupational therapist
  • Physiotherapist
  • Speech therapist
  • Special needs teacher

There could be some inherent genetic or medical conditions or co-morbidities that make the lives of people with ID more complicated. These include physical, medical, and neurodevelopmental conditions like cerebral palsy, autism spectrum disorder, ADHD, depression and anxiety disorders, epilepsy, impulse control behavior etc. Hence, it is extremely important that children with intellectual disabilities are tested for such conditions, and the necessary help given to treat them. The individual’s strengths and requirements are listed, and the support they require to function normally at home, school or workplace, and in the society as a whole; taking all these into consideration, a comprehensive treatment plan is needed.

Early intervention

This is a combination of therapy and specialized support. These may be provided at community health centres, specialized disability services, or hospitals – a therapist may even visit the child’s home in some instances. In some provinces of Australia, the government funds early intervention services, so you may be able to use a combination of these free services, private therapists and community service organizations. Some early intervention therapies offer specialized support for cerebral palsy, vision and hearing impairment, autism spectrum disorder and other specific disabilities.

Assessing your child’s progress

When you begin early intervention, these things need to be kept in mind:

  • The quality of hours spent in therapy is as important as the quantity or number of hours; make sure that the child is properly engaged in those hours.
  • Each child with a specific disability may need a different type of therapy and a personalized program
  • You should not hesitate from trying a different approach if one therapy does not work; in any case, for any therapy to work and make a difference, it does take time. You may only notice small victories initially, but in the long run, they will add up.
  • Assess your child regularly to get a true picture of their progress
  • Federal, state, and local government support can be availed to pay for early intervention therapy and services.

While early intervention is definitely the best way to go, it is never too late to start. Better late than not provide any intervention at all. The brain keeps developing till early adulthood, and some children are not diagnosed till they begin school. You should start the process for intervention whenever you get the diagnosis.

Parents should

  • Not hesitate to ask for help
  • Learn as much as possible about their child’s disability to help them better
  • Form bonds with other parents who have children with ID
  • You will need an abundance of patience
  • Encourage your child to be responsible and independent
  • Get educated about the educational services your child needs
  • Familiarize yourself with the laws in place that will help your child to live a good life
  • Find out about chances in your community for sports activities like Special Olympics, and recreational and social activities your child can participate in.

What is the long-term outlook?

If an individual has an intellectual disability along with other mental/psychological disorders or physical problems, your child is not likely to have an independent normal life and may have a low life expectancy. But a child with mild to moderate disability can have a normal life expectancy, and a fairly normal life, holding a job commensurate with their disability level. They may also be able to live independently and care for themselves.

At Legacy Care Solutions, we have a highly dedicated team of trained professionals who strive to improve the lives of children and adults with ID by providing exemplary support and guidance.