A condition characterised by a deterioration in brain function. Dementia is almost always due to Alzheimer’s disease or to cerebrovascular disease, including strokes. Cerebrovascular disease is often due to narrowed or blocked arteries in the brain. Recurrent loss of blood supply to the brain usually results in deterioration that occurs gradually but in stages. A small proportion of cases of dementia in people younger than 65 have a underlying treatable cause such as head injury, brain tumour, encephalitis, or alcohol dependence. The main symptoms of dementia are progressive memory loss, disorientation, and confusion. Sudden outbursts or embarrassing behaviour may be the first signs of the condition. Unpleasant personality traits may be magnified; families may have to endure accusations, unreasonable demands, or even assault. Paranoia, depression, and delusions may occur as the disease worsens. Irritability or anxiety gives way to indifference towards all feelings. Personal habits deteriorate, and speech becomes incoherent. Affected people may eventually need total nursing care. Management of the most common Alzheimer-type illness is based on the treatment of symptoms. Sedative drugs may be given for restlessness or paranoia. Drugs for dementia, for example donepezil, can slow mental decline in some people with mild to moderate Alzheimer’s disease (see acetylcholinesterase inhibitors).


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