What is an intellectual disability?

Our definition

Intellectual disability is a term used when a person has difficulty understanding, concentrating, learning and remembering new things in their everyday life.

There are thousands of people across New Zealand with an intellectual disability or developmental delay. Each of these people are affected in a different way. The majority of people with a disability live satisfying and happy lives – just like everyone else.

People with an intellectual disability may need support to develop new skills, understand complex information and communicate with other people.

An intellectual disability almost always becomes evident during the developmental years. Despite certain limitations, people with an intellectual disability often have other strengths and capabilities.

People with an intellectual disability are all very different individuals. Some have additional health problems or disabilities that can make their lives harder. Disability is not an illness, but does require people to have some support for daily living.

We use the term intellectual disability as it is the most commonly used phrase and it is endorsed by leaders and activists with an intellectual disability. You may come across the terms learning disability, developmental delay or special needs on other websites and resources.

The Intellectual Disability (Compulsory Care and Rehabilitation) Act 2003 (IDCCR Act) defines an intellectual disability as a permanent impairment that:

  • results in an IQ of 70 or less;
  • results in significant deficits in adaptive functioning in areas such as communication, self-care, home living, and social skills; and
  • becomes apparent before a person reaches the age of 18.

Different types of intellectual disabilities

There are different types of intellectual disabilities, which can be classified as mild, moderate, severe or profound. In all cases an intellectual disability is lifelong.

These categories are not rigid and there are no clear dividing lines between the different groups. It’s important to realise that language is constantly changing. The words we use to describe intellectual disability have changed over time, and will continue to change, as a result of listening to people with personal experience and as a result of changing values and attitudes in society.

IHC believes it’s more useful to address how much support a person with an intellectual disability might need instead of classifying to which group they belong. However, an agreed definition can be useful to let us know which people will be included for funding and support, how to diagnose it and how to plan supports for people to live satisfying lives in the community.

Conditions linked to intellectual disability


•    Down Syndrome
•    Fragile X Syndrome
•    Autism
•    Apert Syndrome
•    Williams Syndrome
•    Fetal Alcohol Syndrome
•    Prader-Willi
•    Phenylketonuria (PKU)
•    Cerebral Palsy

Things you might be interested in

Become a member

IHC members are very important to IHC. We want the support of all New Zealanders to make a difference in the lives of people with intellectual disabilities and their families. If you are interested in IHC and intellectual disability, become a member.

Join our library

The IHC Library is free to use for anyone living in NZ. We have information on all aspects of intellectual disability, autism and other developmental disabilities.

Volunteer

Play a big part in the life of a person with an intellectual disability and the work IHC does by joining our One-to-One Friendship or Skills-based Volunteer Programmes.