In the past 20 years, with the rapid development of society, the incidence of depression has been increasing year by year, and the number of people suffering from depression is increasing day by day. The number of people suffering from depression is increasing day by day. News about depressed people committing suicide is often reported on the Internet, newspapers and other media. Many famous people have suffered from depression, such as Abraham Lincoln, Roosevelt, Nixon, Churchill, Monroe, Hemingway, Darwin, Tolstoy, Chaplin, Mr. Bean, Cui Yongyuan, Wu Han, Li Yong, Fan Xiaoxuan, Robin Williams, Van Gogh, Vivienne. Williams, Van Gogh, Vivien Leigh, Newton, etc. All suffered from depression, and more and more actors and actresses have made public their history of depression, and political and business people have expressed their mental state and outlook on life in some extreme ways. It is evident that depression, a common mental disorder, does not seem as far away from us as we might think. So what kind of disorder is depression? Today let us take you through the most common psychological disorder, depression. The World Health Organization has announced that the global prevalence of depression is between 3% and 5%. This prevalence rate is relatively high, about one in 20 people have depression, which means depression is a common disease. According to the World Health Organization in 2012, there are now more than 350 million depressed people around the world of all ages, and it has become the fourth most common disease in the world, and is expected to become the second most common human disease after cardiovascular disease by 2020. that the number of people with depression in China has reached 90 million. The prevalence of depression is even higher in some special populations, and geriatric depression is one of the most common mental disorders in old age, with a prevalence of 7% to 10% of the elderly population. In addition, the prevalence rate can reach more than 30% if the elderly are accompanied by various physical diseases, so the elderly over 60 years old are especially prone to this disease. There are also some chronic diseases that are likely to be accompanied by depression, such as cerebrovascular disease, diabetes, cancer, cardiovascular disease, Parkinson’s, epilepsy, etc. The prevalence of depression in the population is much higher than in the general population. Depression can have a significant negative impact on the recovery and quality of daily life of patients with these chronic diseases. And many depressed patients fail to receive timely and professional treatment for various reasons, 85% of them will relapse, and 10%-15% of them may eventually die by suicide, and the number of suicide deaths due to depression is as high as 1 million people worldwide every year. This is why the World Health Organization believes that depression is second only to coronary heart disease and other heart diseases as a major health hazard to human beings.