Three characteristics of Alzheimer’s disease that help loved ones distinguish dementia from physiological forgetfulness are: 1, dementia patients with severe forgetfulness, daily life can not take care of themselves; forget all the things experienced in the past, while the general physiological forgetfulness of the person is not. 2, dementia patients in addition to memory loss, but also other symptoms. The simplest calculation can not be carried out, where they can not figure out, or the past will not be something. There are also personality become easy to anger and agitation. 3, dementia patients do not know that they are forgetful, while generally forgetful people can find their forgetfulness, self-overcoming or correct. In addition to the real dementia, the elderly have a kind of senile depression, its performance and dementia is very similar, easy to be mistaken for Alzheimer’s disease. This kind of patients due to mental depression and manifested as a reduction in activities, rarely talk, lazy life, dull expression, seemingly dementia but not dementia, “pseudo-dementia”. Geriatric depression is common in old age and is a functional mental illness. The patient’s mood is low, depressed, emaciated, and feels uninterested in living, spending his days as if they were years. Suicidal behavior may occur in severe cases.