It is possible for depression to heal itself. But depression is also a disease, and for moderately severe patients it needs to be addressed with medication or psychotherapy. Although depression is not like high blood glucose, which can be determined by laboratory tests, patients with the disease will produce changes in neurotransmitter concentrations in the brain and somatic changes, so they should be treated with medication. If the patient only feels unhappy and unable to lift his or her spirits, which resolves on its own within 2 weeks or can be corrected through exercise, etc., the condition is not a depression but a depressive state. The state of depression may recur several times at different times in a person’s life. Depression must be treated by a doctor, and depression can be improved through medication, psychotherapy, and increased exercise.