They followed 486 patients, aged 60 to 90, for six years. During this period 33 subjects developed Alzheimer’s. The researchers said those who had experienced depression were 2.5 times more likely to develop dementia. The risk was even higher among subjects who had suffered from depression before the age of 60, the researchers found.
‘We don’t know yet whether depression contributes to the development of Alzheimer’s disease or whether another unknown factor causes both depression and dementia,’ said the authors.
Neurology (2008) 70: 1258-1264