If hallucinations occur, they are mainly due to the following reasons: first, the problem of schizophrenia, which is a serious mental illness in which patients mainly experience symptoms such as hallucinations, delusions, behavioral disorders, and introverted thinking. If symptoms such as hallucinations and hallucinations suddenly appear, the problem of schizophrenia should be considered first. Second, there may be severe depression. The main manifestation of depression is depressed mood, unhappiness, pessimism, negativity, and low self-evaluation, but severe depression can have psychotic symptoms, mainly the symptoms of hallucinations. Third, it may be caused by organic brain diseases, such as brain hemorrhage, cerebral infarction or Alzheimer’s disease, may appear hallucinations, with phantom smell, phantom vision as the main performance, the above are the more common reasons for hallucinations.