Frequent bad moods and low moods are often more likely to be depression and its related disorders. Depression is a group of syndromes that are characterized by persistent and significant depression. Its main clinical manifestations are low mood, bad mood, unhappiness, slow brain response and lack of thinking and planning for the future, accompanied by low self-esteem, feeling useless, self-blame and self-sin. Many patients will suddenly lack interest and pleasure in things they are interested in, as well as feelings of uselessness, incompetence, despair, and a general feeling of fatigue and weakness, and some patients may have thoughts and behaviors of self-injury and suicide. If this situation lasts for more than two weeks, with the above symptoms occurring for the vast majority of each day, and seriously affecting social functioning, depression needs to be considered. Depression is a relatively common disorder in clinical practice, and clinical recovery can be achieved through antidepressant systemic and standardized treatment. Therefore, once depression is diagnosed, early diagnosis and treatment are recommended to achieve clinical recovery as soon as possible.