In elderly people with mental disorders, organic problems should be ruled out first. The most common are organic brain problems, such as cerebral infarction, cerebral hemorrhage or traumatic brain injury, which require imaging tests, such as head CT or head MRI, first. If organic brain disease is found during the examination, the primary disease must be treated first. When the primary brain disease is treated, the patient’s psychiatric symptoms will gradually resolve. Functional disorders, such as common geriatric depression, geriatric anxiety and geriatric affective disorders, are only considered if the organic brain examination of the elderly does not reveal any abnormalities. Other elderly people who suddenly develop psychosis, feel that someone is harming them and become more absurd in their behavior need to be alerted to syphilitic encephalopathy. This is because syphilis will be latent in the body for many years and will develop in old age, progressing to neurological syphilis with psychotic symptoms. So older adults who experience sudden psychotic disorders also need to be checked for syphilis pallidum spirochetes. Most psychiatric disorders in the elderly require medication, and psychiatric medication for the elderly must be started in small doses, applying 1/4 or even 1/8 of the adult dose.