Pseudodementia: A reversible group of symptoms that resemble the manifestations of dementia due to non-organic factors. It is generally referred to as depressive dementia, or depressive dementia syndrome. In depressive episodes, patients have slow thinking, difficulty in association, slow reaction, little active speech, depressed mood, dull expression, reduced interest, reduced movement, lazy life, especially in severe depressive episodes, resembling “dementia”, but not the real dementia caused by organic factors. Pseudo-dementia can be recognized from the following ten aspects: (1) previous history of depression or mania; (2) the main manifestation of depression; (3) the acute onset of the disease under the influence of adverse life events; (4) the dementia is reversible and can be completely restored to normal; (5) there is generally no memory or intellectual impairment, some depressed patients are slow to answer questions or do not answer, slow movements, and often have low scores on intelligence tests. (6) The disease has the characteristics of heavy in the morning and light at night; (7) The course of the disease is episodic, but when the depression is not episodic, it is completely normal; (8) There is the phenomenon of approximate answer: the answer is not correct, but the content of the answer is similar to the content of the question; (9) There are no corresponding physical and neurological signs and positive laboratory test results; (10) The antidepressant (10) good effect of antidepressant treatment. However, the following special “dementia” should be noted: (1) hysterical dementia: on the basis of certain character defects, the acute onset of the disease under the influence of general psychological factors, manifested as child-like dementia, approximate answers, amnesia, rigidity, etc., the course of the disease fluctuates, the course of the disease recurrent, implying that the treatment “dementia ” remission. (2) Early-onset depressive syndrome of dementia: about 35% of patients with dementia may present with early depressive manifestations and are easily misdiagnosed as depression. (3) Psychogenic dementia: dementia-like phenomena appear under strong mental trauma, mental stimuli disappear, and “dementia” can be relieved by appropriate treatment and handling. (4) Imitative dementia: there is a clear personality defect and the imitator is partially self-fraudulent. (5) Pseudo-dementia.