Skip to main content Accessibility help
  • Print publication year: 2015
  • Online publication date: January 2018

14 - Ageing in people with disorders of intellectual development

from Part 4 - Service provision
    • By Gregory O'Brien, (deceased) formerly Professor of Developmental Psychiatry, Northumbria University and the University of Queensland, Paul White, Dual Diagnosis (Intellectual Disability) Service, Park Centre for Mental Health, Wacol, Queensland, Australia
  • Edited by Marc Woodbury-Smith
  • Publisher: Royal College of Psychiatrists
  • pp 264-276


Until very recently the notion that there might be a population of older adults with serious intellectual and developmental disabilities was not widely considered. Most efforts in care, treatment, service development and planning were focused on children and ‘early intervention’. Now there is a growing population of elderly adults with developmental disabilities because of innovations in health and social care. This chapter focuses on health and general care needs of those with disorders of intellectual development (DID), with a particular focus on comorbid dementia.

Increasing longevity

People are living longer. The life expectancy of ‘three score years and ten’ has not only been replaced by a much older age but has also been steadily increasing. Recent figures for England and Wales quote a life expectancy for boys born in England and Wales in 2009–11 of 78.7 years and 82.6 years for girls. This rising life expectancy is largely due to advances in nutrition and in medical services.

The overall severity of intellectual disability is a strong determinant of life expectancy among people with DID. Recent estimates are framed for high-income countries, given that life expectancy is so inextricably linked to the availability of healthcare. It is estimated that in the year 2000, life expectancy for adults with mild intellectual disability was 70 years, while life expectancy for adults with severe intellectual disability was 60 years (Bittles & Glasson, 2004). In the UK, Valuing People, the official government policy document, estimated that there were over 200 000 people over the age of 60 years with DID in 2000 (Department of Health, 2001). It was further estimated therein that this will increase by 1% per year for at least the next 15 years, due to further increased longevity. In the USA, the American Association for Intellectual Disability estimated that at the turn of the century there were between 600 000 and 1.6 million adults over the age of 60 years with intellectual disabilities and other similarly disabling developmental disabilities (Braddock et al, 2008). The most recent US estimate for the average life expectancy of adults with DID is 66 years and rising (Fisher & Ketti, 2005).