Alzheimer's Disease is a progressive, degenerative disease of the brain. Usually the first symptoms are problems with memory such as routinely forgetting recent events, appointments, names and places. The person affected may also begin to have difficulty with language and routine, everyday tasks. Mood swings and personality changes such as apathy and irritability are also common. In the middle stages, the person may wander, become disorientated in familiar surroundings and may loose inhibitions and a sense of appropriate behaviour. Finally, the person with later stage Alzheimer's disease will be unable to do things independently and will require constant care. The time scale for the disease can vary greatly, lasting anything from 2 to 20 years. Although primarily a disease of those over 65, Alzheimer's Disease can affect people in their forties and fifties.

It is estimated that more than 35,000 people in Ireland currently have dementia, of which Alzheimer's disease accounts for more than half of all cases. There is no single cause of Alzheimer's disease and there is currently no cure, although there is ongoing research into the treatment of the disease and there are options available that may help to slow its progression.

The role of the Alzheimer Society of Ireland is to raise public awareness and provide information; to provide quality, dementia-specific care; to support carers and families of people with dementia; to campaign for better statutory services, including specialist services for younger people with dementia; to represent the views, needs and concerns of all affected by dementia; and to influence public policy with regard to care and support services.