What is intellectual disability? - Afea Care Services
June 6th 2023

The term intellectual disability is used to describe a lifelong condition that affects a person’s ability to understand information and to learn and apply new skills.

A person with this condition can experience challenges in learning everyday life skills, such as social interactions and hygiene routines. Almost 60% of people with intellectual disability have severe communication limitations.

According to Inclusion Australia, the national peak body for intellectual disability, 460,000 people in Australia are diagnosed with the condition.

Symptoms and Diagnosis

The condition affects functioning in two areas of life:

  • Intellectual functioning, such as learning, problem solving, judgement
  • Adaptive functioning, or activities of daily life such as communication and independent living

Symptoms begin during childhood, with language or motor skill delays seen by age two. Symptoms may include:

  • difficulty speaking
  • memory problems
  • lack of curiosity
  • aggressive behaviour
  • difficulty expressing emotions
  • trouble following simple instructions
  • difficulty with personal care tasks, e.g. getting dressed or taking a bath

To diagnose, clinical professionals use a comprehensive test of intelligence, such as an IQ test. However, the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) requires another layer of diagnostic criteria, in that the clinical professional must also consider the person’s ability across three areas:

  1. Conceptual – language, reading, writing, math, reasoning, knowledge, memory
  2. Social – empathy, social judgment, communication skills, the ability to follow rules and the ability to make and keep friendships
  3. Practical – independence in areas such as personal care, job responsibilities, managing money, recreation, and organising school and work tasks

The condition is identified as mild, moderate, severe or profound. (See details of each category here.)

A huge majority – about 85 % – of people with intellectual disability have mild intellectual disability, described below:

  • IQ 50 to 70
  • Slower than typical in all developmental areas
  • Able to learn practical life skills
  • No unusual physical characteristics
  • Functions in daily life

People with moderate to profound intellectual disability are likely to meet the disability requirements for the NDIS.


Intellectual disability is caused by several factors. It can be associated with a genetic syndrome, develop following a childhood illness or injury, or may be caused by exposure to toxins and other environmental influences. Examples include:

  • Down Syndrome
  • Fragile X Syndrome
  • Childhood brain injury
  • Brain malformation
  • Infection during pregnancy
  • Exposure to lead or mercury
  • Severe malnutrition
  • Fetal exposure to alcohol, drugs or other toxins
  • Severe cases of early childhood illness, such as meningitis, measles or whooping cough
  • Trauma during birth, such as oxygen deprivation or premature delivery

Supports and Services for Intellectual Disability

Every person with an intellectual disability is different, with different needs to lead a happy and independent life.

Many of our clients at Afea are people with intellectual disability. With the proper support, a person diagnosed with the condition can learn new skills.

Areas of support may include:

  • Communication – see these communication tips from the Council for Intellectual Disability
  • Self-care, such as personal hygiene
  • Social interaction
  • Community access
  • Financial education
  • Additional support in school

Early diagnosis can help people access assistance as soon as possible. A diagnosis often determines eligibility for services, including the NDIS.

If you or someone you know have been approved for NDIS support, contact us now and we’ll develop a care plan designed just for you.

For further information, please visit:

Inclusion Australia

American Psychiatric Association

Council for Intellectual Disability

Australian Institute of Health and Welfare

Afea Care Services
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