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What is ID?

Description of intellectual disability

People with ID have a wide range of skills, capabilities, interests, strengths and needs. It is important not to make assumptions about
these. Each person with ID is unique and will require an individualised approach to rneeting their personal healthcare needs.

Intellectual disability (also known as intellectual developmental disorder) is a conditon involving impairment of general intellectual
abilities which begins during the developmental period and impacts significantly on a person's adaptive functioning.3 Impairments in adaptive functioning can occur in three areas, including:

  • conceptual -e.g. language, reading, writing
  • social -e.g. empathy, interpersonal communication skills, social judgement
  • practical -e.g. personal care, self-management, lifestyle.

Assessment is usually based on the severity of deficits in adaptive functioning, which can be determined by clinical and standardised cognitive tools. Formal testing of intellectual abilities will enhance the person's assessment. The severity of ID can be described clinically as mild, moderate, severe or profound.

A person's functional capacity may be affected by their health and other factors, including:

  • the specific characteristics and aetiology of their diagnosis
  • related comorbidities (physical, rnental or behavioural)
  • family and community supports available
  • access to health services (including specialised health services)
  • understanding of and ability to act on preventive health advice
  • housing
  • financial situation
  • educational and work opportunities
  • challenging behaviour
  • other health conditions (diagnosed or undiagnosed).

Health conditions common to the general population but also experienced by people with ID (such as gastro-oesophageal reflux, heart conditions, mental ill-health, presence of autism, sight and hearing difficulties) all compound the impact of a person's ID on their functional capacity.

ID can be confused with other conditions distinguished by subsequent loss of cognitive and adaptive functions. For example, acquired brain injury can affect a person's functional capacity and may be caused by accident, abuse, stroke or drugs and alcohol. If this injury happens during the developrnental period and persists, the person is considered to have ID.
Dementia is different from ID in that it is not a developmental disorder and it is usually characterised by progressive deterioration in cognitive function which impact the person's ability to carry out their daily function. Sometimes dementia may also affect people with ID.

There is a link between early onset Alzheimer's disease and Down syndrome:4

Developmental Disability is a broad term used to describe a number of physical and cognitive conditions arising in the developmental period.

The right to self-determination

People with ID have the right to make choices about their lives.

In order to understand and communicate their choices and preferences, people with ID may require support.5

Health professionals may also require expert and individualised support to understand the person's needs and choices and their role in the process.

Complex needs and people with ID

In all age groups, people with ID experience a higher prevalence of health conditions. These can either be associated with their disability (as part of a syndrome) or be direct or indirect consequences of the ID. Such health conditions are often multiple and complex and may include sensory impairment and epilepsy, physical illness or disability as well as mental health and behavioural challenges. Health conditions may also exacerbate functioning deficits in ID. For example a person with ID might have difficulty with muscle coordination for chewing and swallowing. Positioning difficulties as a result of scoliosis may further limit their ability to chew and swallow food, and then may increase their risk of aspiration pneumonia.

Chronic, complex health conditions are increasing across the age spectrum. One cohort comprises those with conditions of childhood which may have been life limiting in the past. Now these people are surviving well into adulthood with a spectrum of needs and disabilities and this may include ID. For example, people with Down syndrome are now living into older age

Factors that contribute to the complexity of health needs of people with ID include having multiple disabilities, severity of ID, dual diagnosis of ID and mental illness, severe, multiple or deteriorating health conditions, behaviours involving harm to self or others, alcohol and/or drug issues and issues relating to past experience of trauma or neglect. Situational factors can include socioeconomic disadvantage, lack of natural support,6 family/carers stress, breakdown in care arrangements, young people leaving care, involvement in the criminal justice. system and multiagency involvement in provision of support.

Cognitive and communication impairments mean people with ID often rely on carers or proxies to access healthcare. People with complex support needs may encounter additional challenges to accessing timely and high quality healthcare. This is in part due to the need for health services to provide more accessible services and skilled staff.

A particular challenge for health services is ensuring that all people with ID are catered for by the mainstream health system, including those who have complex needs. This has implications for NSW Health in terms of the coordination of healthcare and the need to develop partnerships with the disability sector to support health care delivery and recognise the individual's need to navigate a range of healthcare specialties, along with disability, educational and social services. NSW Health has placed particular emphasis on integrated care, the engagement of primary care providers/networks and partnerships between providers as well as with people with ID and their families.

This emphasis will better support the healthcare needs of people with ID.

3 American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Washington: American Psychiatric Association; 2013.
4 Centre for Developmental Disability Health (CDDH) Victoria. Down syndrome and Alzheimer's disease. Melbourne: CDDH; ISBN 978-1-921570-03-2
5 Capacity toolkit from the NSW Attorney General's Department about a person's capacity to make their own decisions
6 Natural supports are the help and care that someone receives from relationships that occur in everyday life, from friends. family or the community - NDIS.