Intellectual Disability (Revised)

To be diagnosed with an intellectual disability, children must have the following:
  • Significantly below-average intelligence. Deficits in intellectual functions such as reasoning, problem solving, planning, abstract thinking, judgement, academic learning, and learning from experience must be confirmed by both clinical assessment and individualised, standardised, intelligence testing. The child’s intelligence quotient (IQ) will generally score at 70 or below.
  • Significant difficulties in adaptive functioning that result in failure to meet developmental and sociocultural standards for personal independence and social responsibility. Without continuing support, adaptive deficits limit functioning in one or more activities of daily life, such as communication, social participation, and independent living, across multiple environments, such as home, school and community. These difficulties are measured using a test of adaptive behaviour.
  • A history of developmental difficulties or delay before age 18. Children with a mild intellectual disability may not be identified or diagnosed until they begin school or, in some cases, several years later. Early years teachers play a significant role in identifying children who are not learning at the rate of their peers and referring them for assessment with a psychologist. All referrals must have parents consent.

Note children with a mild intellectual disability typically have an IQ 50/55 to 70, moderate intellectual disability IQ 35 to 49/54, severe intellectual disability IQ 20 to 34 and profound intellectual disability below 20.

Children with a mild to moderate intellectual disability at school

Children with intellectual disabilities learn more slowly than same age peers. This will inevitably lead to the accumulation of a smaller store of knowledge and skills, so it is important that teaching promotes useful learning. These children may exhibit some of the following characteristics:

Difficulties with thinking and reasoning

Thinking and processing information and new learning occurs at a slower rate and to a lower level than peers. Children with intellectual disabilities do not usually learn by picking things up incidentally. They learn best through direct teaching and use of concrete aids.

They may have a specific difficulty with:

  • Cognitive processing, requiring more time than other children
  • Comprehending abstract reasoning and thinking tasks
  • Cause-and-effect relationships
  • Categorising
  • Generalising and applying what is learnt to different situations and contexts.
Difficulties with communication and speech and language skills

They may have difficulty with:

  • Receptive and/or expressive language
  • Sentences and vocabulary, which are more limited and less complex than peers
  • Use of language, which is often very concrete
  • Understanding and following complex instructions and open-ended questions
  • Finding the confidence and competence needed to speak in front of the class.
Learning difficulties

They generally exhibit the following characteristics when learning new information and behaviours:

  • Significantly slower learning than same age peers, as processing, retention, and retrieval of information from memory is difficult
  • Need repetition and practice for new learning to become established
  • Academic progress that is significantly behind peers (and the gap widens with age)
  • Stronger progress in academic areas that do not require higher level reasoning and complex concepts. Generally, there is a preference for kinaesthetic, visual and multi-modal learning.
  • Difficulty learning and applying basic skills such as punctuation, spelling and number facts
  • Need a long time to complete a task
  • Difficulty forming ideas or concepts, and with abstraction
  • Difficulty with generalisation, so what is learnt in one area may not be applied to another area.
Difficulties with attention and task completion

All children can experience attention problems at times. However, children with an intellectual disability are more likely to demonstrate:

  • Short attention span
  • Short-term memory problems
  • Difficulty with motivation and distractibility
  • Difficulty initiating, beginning or staying on task, and completing a task.

They can quickly become fatigued in a classroom where there are many demands on them; and can appear to have learnt a skill one day, but completely forget it the next day.

Difficulties with organisational skills

All children can be disorganised and off task at times. However, children with an intellectual disability can have more difficulty with:

  • Organising work materials, for example, pens, pencil cases, diaries, timetables, notebooks, and other equipment
  • Organising information
  • Managing time and space
  • Sequencing and arranging things in order.
Difficulties with self-regulation

Children with an intellectual disability can have poor emotional intelligence. They may have difficulty understanding and regulating their emotions and recognising, understanding and managing the emotions of others. This may manifest in behaviours such as angry outbursts, over excitability, impulsivity, and mood swings.

Behaviour and emotional difficulties

Children with an intellectual disability are socially and emotionally less mature than same-age peers and this can give rise to challenging behaviours. Most children with an intellectual disability are passive and gentle however some can be impulsive and/or aggressive. In some cases, aggression may be the way a child with an intellectual disability has learnt to exert influence over situations or people.

Some children with an intellectual disability can be emotionally volatile and non-compliant. Challenging behaviour typically stems from frustration about not having their needs met, inability to complete a task or lack of understanding about what is required of them. This can lead to:

  • Low self-confidence and self-efficacy
  • Stress and limited coping strategies
  • Anxiety or worry
  • Depression or sadness
  • Withdrawn behaviours
  • Aggression
  • Rule-breaking behaviour.

Children with an intellectual disability often experience repeated failure. They may be dependent on adults for assistance with many tasks including daily living activities.

Social skills difficulties

Children with an intellectual disability may have poorly developed social skills and problems understanding things from another person’s perspective. In addition, social anxiety and sometimes poor articulation, can lead to conversational difficulties. As a result, they may have difficulty:

  • Making and maintaining friends
  • Understanding social cues and rules
  • Understanding non-verbal cues, for example in games
  • Dealing with groups of unfamiliar people.

In many ways, the child with an intellectual disability functions as a much younger child, and at times may prefer to play and be with younger students.

It is important to note that children with an intellectual disability may not exhibit many of these characteristics. Equally children who do not have an intellectual disability may display some of these characteristics at times.

Co-existence with other disorders

Intellectual disability can co-exist with other mental health and medical disorders. Some children with an intellectual disability will have a diagnosis of one or more of the following: ADHD, mood disorders, anxiety, or pervasive developmental disorders such as Autism Spectrum Disorder. The prevalence of a psychological disorder in children and adolescents with an intellectual disability is estimated to be 36%. The prevalence of conduct disorder is about 20%.[2]

Intellectual disability can co-exist and be due to genetic disorders such as Down syndrome or Fragile X syndrome.

Children with an intellectual disability are more at risk of anxiety and depression than typically developing children.

Due to a lack of understanding of the emotional states of themselves and others, children with an intellectual disability frequently experience higher levels of anxiety. Anxiety manifests from:

  • Frequent feelings of frustration through not understanding the world around them
  • Fight or flight behavioural responses, often interpreted by others as aggression or challenging behaviour
  • Lack of success and frequent failure leading to feelings of lack of control and poor self confidence
  • Being made fun of and subjected to bullying and teasing due to lack of understanding of social skills and norms
  • Weight issues from over-eating. Obesity is common
  • Physical Issues, such as poor coordination and other gross and fine motor difficulties
  • Poor self-concept
  • Fear of getting lost, losing things, reliance on others and fear of losing main care givers
  • Fear of change.

Anxiety can often manifest as generalized anxiety, social anxiety or specific phobias.

These co-existing conditions can persist into adolescence and adulthood without effective support and intervention.


There is no specific treatment for intellectual disability as it is a lifelong, neurodevelopmental and pervasive condition. Treatment, therefore addresses comorbid issues which are common in this population. Comorbidity refers to the presence of more than one disorder or condition alongside the primary diagnosis (of intellectual disability).

It is critical that children with an intellectual disability are assisted throughout their schooling and beyond with appropriate interventions and management. Targeted support and timely interventions can help maximise opportunities for the development of self-regulation and optimum learning, helping to minimise low self-confidence, inappropriate behaviour, poor routines or maladaptive mannerisms.

As previously noted, while children with an intellectual disability can present with a broad range of challenges, this does not mean they cannot learn. They will be slow learners in many areas throughout their life, but with appropriate support, supervision and positive reinforcement of their ability to function independently at school and in society will be optimised.

Strategies to support the child with an intellectual disability

Make ‘reasonable adjustments’ to the curriculum

Teachers are required to make ‘reasonable adjustments’ for students with disabilities. Ensure these strategies are inclusive where possible, part of accepted practice, discreet, negotiated via consultation, support independent and continued learning and engagement. For example,

  • Provide ‘hands on’ concrete aids, manipulatives, drawings, diagrams and mathematical tools to support learning and completion of tasks. For example, when teaching numeracy concepts such as addition, subtraction or length multisensory activities can be helpful; when teaching letter formation, you might ask the child to write the letter on an outside path in chalk, write the letter with their finger in sand, trace the letter with a glue stick and then cover the paper in glitter, or ‘write’ using felt letters that can be cut and pasted down to make letters and common words.
  • Repetition of the same material over time will help consolidate new learning and skills for many children with an intellectual disability.
  • Use visuals as much as possible to take the load off the child’s work memory and build independence to move through a task.
  • Motivate by aiming tasks at the child’s level of interest and understanding. This will promote engagement and persistence.
  • Digital curriculum resources from the National Digital Learning Resources Network such as interactive learning resources, tools, film clips, sound files, photographs, maps and teacher support materials can help make learning meaningful.