Amnesic syndrome is also known as Korsakoff’s syndrome or amnesic fictitious syndrome. 1. Clinical manifestations Clinical features are memory impairment, temporal orientation disorder, fictitious syndrome and prograde or retrograde amnesia. Patients begin with an inability to recall events that occurred after their onset, or things they have just done. The amnesic syndrome can often be combined with memory errors, and the patient often fills in the gaps of memory loss from previous experiences in the form of misconfigurations or fictitious disorders. (1) Psychiatric disorders due to alcoholism Patients can suffer from severe memory deficits after long-term alcohol consumption, especially near memory deficits, and they cannot remember anything new that happened. In addition, there are behavioral and emotional changes, and the patient often stays in one place. Emotions are expressed as euphoria, etc. The diagnosis is based on the history of alcohol consumption. (2) Post-traumatic amnesia syndrome is an organic disorder in which memory loss is a prominent clinical manifestation long after the acute phase of traumatic brain injury has passed. Both near and distant memory are impaired, and the near memory loss is particularly pronounced, but consciousness is clear, other cognitive activities are not impaired, and memory gaps are often filled by fictitious episodes. (3) Subarachnoid hemorrhage A manifestation similar to Korsakoff’s psychosis may rapidly appear, and the patient has disorientation. This type of amnesic syndrome often occurs after an asymptomatic interval of several days or weeks, lasts briefly, and mostly recovers quickly after several weeks. The diagnosis is confirmed by the sudden onset of severe headache, vomiting, positive meningeal irritation, and homogeneous blood in the cerebrospinal fluid by lumbar puncture. (4) Mesencephalic tumor Significant amnesia may occur, with inability to remember or reversal of back and forth for newly occurred events or newly learned things, but better memory for more distant events or previously learned things, and other aspects of cognitive function remain better, but the manifestation of fictitious symptoms is more obvious. CT, cranial radiographs, and cranial ultrasound are often positive. (5) Alzheimer’s disease Patients may exhibit jealous delusions and memory disorders, initially only near-memory impairment, poor orientation, on the basis of this, there is a decline in calculation, low judgment, and later speech disorders and aphasia, loss of use, loss of recognition, etc., resulting in restlessness, some patients go out to run, forget the way back, late at night in the street head corner, repeatedly do some monotonous, stereotypical, meaningless movements. Some patients may go out and forget where they are going, or wander into the street at night. In addition to memory disorders, fictitious and misconceptions may occur, accompanied by personality changes. The diagnosis can be confirmed according to the age of onset, medical history, CT and pathological examination. (6) Cerebral atherosclerotic mental disorder Patients may show affective disorder, consciousness disorder, personality disorder and memory disorder. In the early stage, near memory disorder is predominant, and later visual and auditory memory are also significantly diminished, and in the late stage, distant memory is more obviously diminished, and amnesia and fictitiousness can be produced. These patients often have some neurological signs and symptoms. Cerebral hemogram is more valuable.