Depression is a type of mental illness, and there are several degrees of depression: mild, moderate, severe, and very severe. Mild depression is not particularly serious, while moderate to severe or very severe depression is a more serious mental illness. Patients with severe depression will have the tendency or behavior of self-injury or self-harm, which is more threatening to their health. Therefore, if you have the tendency of depression, you must go to the hospital for examination in time. It is recommended to do the relevant depression test scale in the department of psychiatry of public hospitals, and to clarify the degree of depression through the doctor’s consultation, medical history and psychiatric examination, in order to know the severity of the disease and how much it affects the social function, and further take the next step of treatment. Mild depression can be self-adjusted or psychotherapy can be applied, while moderate to severe may require antidepressant medication to help adjust.