Median life expectancy for people with Down Syndrome is 60 years for those living in developed countries. Premature ageing is seen from 40 years of age. In addition, the incidence of Alzheimers type dementia occurs earlier and more frequently in Down Syndrome due to the presence on chromosome 21 of a number of genes associated with dementia, and the premature development of changes in the brain such as amyloid plaques and neurofibrillary tangles. The prevalence of dementia is 10% in those 40 – 49 years of age, and 40% in people with Down Syndrome over 50 years of age.

Early signs of dementia may include changes in behaviour or personality, such as apathy, anxiety and agitation, decrease in social interaction. It is important to rule out health problems such as visual or hearing loss, thyroid dysfunction or other health problems which could produce similar signs, and a full medical work up should be done. Depression is frequently seen in adults with Down Syndrome with a higher incidence in those with dementia. Regular mental health screening in those over 35 years of age may identify early signs and allow for environmental adaptations and supports as well as medical treatments which may slow the progress of dementia.

Health problems increase as dementia progresses, with epilepsy, swallowing difficulties, respiratory infections, incontinence, loss of mobility and myoclonic seizures becoming more prominent.

Presentations at DSMIG Meetings

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Additional Resources

Book Chapter -Mental Health and Dementia in Adults with Down Syndrome

Annus, Wilson and Holland,


Down Syndrome – Current Perspectives Mackeith 2015

ds-current-perspectives-book-coverEdited by Richard Newton , Shiela Puri and Liz Marder


Alzheimer’s Disease: a Guide for Parents and Carers

Down syndrome association ( England Wales and N.Ireland) Health series leaflet


An Introduction to Alzheimer’s Disease      and

A Caregiver’s guide to Down Syndrome and Alzheimer’s Disease   National Down Syndrome Society (USA)


Learning Disabilities and Dementia  Alzheimers Society