Depression is a common mental illness, mainly manifested by low mood, reduced interest, pessimism, slow thinking, lack of initiative, self-blame, poor diet and sleep, fear of suffering from various diseases, feeling unwell in many parts of the body, and in severe cases, suicidal thoughts and behaviors. The manifestations of psychological depression are different from other neurological psychological disorders, and generally patients with psychological depression sometimes ignore their problems due to the prevalence of symptoms. The incidence of depression in adolescents has been increasing in recent years, but people are still “unaware of the true nature of the disease”. A psychologist has conducted a survey on 162 adolescent patients aged 15-23 years old who “came to the psychological specialist”, and the results showed that the recognition rate of adolescents themselves is almost “0”, and the recognition rate of schools, families and society is less than 1% on average. In some general hospitals, the recognition rate is only about 15%. Before the 1970s, it was thought that children could not have depressive episodes, and even if depression occurred during adolescence, it was often seen as a “normal” part of development, or as “adolescent turmoil”. Later in the 1970s, studies found that a cluster of symptoms similar to adult depression could be seen in children and adolescents. In 1971, the European Federation of Child Psychiatrists declared that it was necessary to prove that depression in childhood and adolescence was a significant proportion of mental disorders in children and adolescents. Since the 1980s, there has been a convergence of opinion among researchers that adolescent depression does exist, but with some characteristics of its own. Criteria for the course of the illness: 1. The symptom criteria and severity criteria have been met for at least 2 weeks 2. Some schizophrenic symptoms may be present but not consistent with a diagnosis of schizophrenia. If both symptom criteria for schizophrenia are met, the criteria for depressive episode are met for at least 2 weeks after remission of schizophrenic symptoms Exclusion criteria: Exclusion of organic psychiatric disorders, depression due to psychoactive or non-addictive substances. How is adolescent depression classified clinically? 1. Acute depression: A relatively clear trigger, the affected person presents with obvious depressive symptoms. Most of them involve severe loss events, with an acute onset and progressive worsening of symptoms. It seriously affects learning and life. Acute depression usually lasts for a short time, and recovery is faster with timely treatment. 2. Chronic depression: There are often multiple separations from parents or other traumatic events, but there are no sudden major triggering factors. These children have poor ability to adapt to the environment before the disease, depression appears gradually, and there are often obvious physical symptoms in addition to emotional depression. 3.Incognito depression: The depressed mood of the child is not obvious, but often manifests as behavioral problems and a variety of physical symptoms. Sometimes depression can be periodically expressed.