The 20-year-old patient’s memory loss is considered to be caused by functional reasons, mainly the following: 1, may be related to the patient’s bad habits, such as often stay up late or sleep deprivation is likely to lead to brain nerve dysfunction, manifested as forgetfulness, memory loss. 2, if the patient usually smokes more, drink more, continue to be in a state of stress and tension will make the patient’s brain cells produce fatigue The problem of memory loss can occur. The patient’s memory loss can be caused by excessive smoking, alcohol consumption, vitamin deficiency and malnutrition. 3, 20-year-old patients with memory loss can not be ruled out as a result of organic diseases. If a patient suddenly develops severe memory loss, it may be caused by autoimmune encephalitis or other organic diseases, and must be promptly seen, examined and treated.