1.Depressed mood (depressed state of mind): It is the core symptom of depression disorder. Patients feel depressed, “can not lift the spirit”, feel like a “dark cloud”, often cry, no sense of joy. On the background of low mood, the patient’s self-evaluation is often reduced, feeling that he or she is less capable, inferior to others, can’t do anything well or can’t do anything. At the same time, patients can develop a sense of uselessness, disappointment or despair, patients feel that everything is bad for them personally, the future is bleak and everything is hopeless. Some patients have a deep sense of guilt or even guilt. Patients can feel that life is meaningless and that life has no meaning. Not only is there no meaning, but living is the same as suffering and sinning, and life is worse than death. Patients are prone to suicidal thoughts, suicide attempts or death by suicide. This should be highly alert. 2. Interest: Most of the patients will experience a loss of interest and a lack of enjoyment. Patients are often unable to get pleasure from daily life and activities, and it is difficult to raise interest even in activities that used to be of great interest. Therefore, patients often give up some of their favorite activities (such as sports activities, amateur collection, social interaction, etc.), often even daily work, life enjoyment and the joy of family, etc. are not interested, do not experience happiness, behavior retreat. 3. Fatigue and loss of vitality: Patients feel that their whole “person” has collapsed and fallen apart. The patient needs to be urged or pushed to do anything (including self-care), otherwise he or she does not want to move at all. At the beginning, the patient often feels that he or she is “unable to do anything”, but later on, although he or she wants to struggle to do something, he or she can’t keep going. One patient said graphically that he or she is “a puddle of mud – can’t get up.” Most people with depression have varying degrees of fatigue and do not regain energy effectively through rest or sleep. They have difficulty with work and often fail to complete tasks. Sometimes, fatigue may also be associated with sleep disturbances. Other patients feel painful and have difficulty expressing it. Many patients are reluctant to seek medical attention, convinced that their physicians and others cannot help their condition and that no one can save them. Some patients feel that their days are like years, they are extremely lonely, and they feel alienated from people around them (including family members). 4. Thinking and speech: Patients with depressive disorder tend to have slower thinking activities and reduced speech activities. The thinking process is difficult, and some simple problems take longer to complete. The ability to make decisions is significantly reduced, becoming indecisive, indecisive, even for some small daily matters are difficult to make decisions. People with depression often speak very slowly. It is difficult to talk to them because they take a long time to answer questions and often reply with simple words. 5. Appetite, weight and sleep: Most depressed patients show a loss of appetite, and they eat very little. Due to the small amount of food and poor digestive function. Patients often lose weight. A few patients also show an increased appetite. Most depressed patients have some form of sleep disturbance. This can manifest as difficulty sleeping. Sleep is not deep and wakes easily, typically with early awakening. Patients who have difficulty sleeping are often accompanied by symptoms of irritability and anxiety. Similarly, a few patients can be seen clinically with excessive sleep. 6. Anxiety or agitation symptoms: Many patients with depression have symptoms of anxiety and nervousness. Patients are worried and fidgety, constantly walking, pacing back and forth, rubbing their hands together, and moving aimlessly. Such symptoms are often more prominent in elderly depressed patients. 7, low libido: low libido is quite common in depressed patients, no demand for sex and lack of pleasure. Suicidal ideation, suicide attempts and suicide: Due to low mood and low self-esteem, patients are prone to low self-esteem, self-blame and despair, so depressed patients are prone to suicidal ideation, with thoughts of death repeatedly circling in their minds, even thinking about the time, place and way of suicide. Suicidal ideation in depressed patients is often stubborn and recurrent. Driven by suicidal ideas, some patients will make suicide attempts. 9, other symptoms In addition to the above symptoms, depressive disorder can also have a variety of other symptoms, including a variety of physical complaints, common complaints include headache, neck pain, low back pain, muscle cramps, nausea, vomiting, swelling of the throat, dry mouth, constipation, burning sensation in the stomach, indigestion, flatulence, blurred vision, and painful urination and so on.