Most common cause dementia in an adult is
Dementia is a chronic organic mental disorder characterised by impairment of intellectual function, impairment of memory, deterioration of personality with lack of personal care Alzheimer&;s is the commonest cause of dementia seen in about 70% of all cases of dementia in USA. It is more commonly seen in women (Ref: a sho textbook of psychiatry, Niraj Ahuja,7th edition, pg no23)
Alzheimer's
Multi-infarct
Pick disease
Metabolic cause
Organic mental disorders