Depression, although not a terminal disease like cancer, can cause great pain, no less than the mental torture that cancer can bring to a person. Currently, depression has become one of the most common diseases in the world. Data show that more than 350 million people are suffering from depression. Depression is already the leading cause of incapacitation, and two-thirds of those affected will commit suicide. Depression is such a common and painful illness, yet it is often overlooked by the general public. In the UK, three-quarters of depressed patients are not diagnosed or treated in a timely manner; even for those who are diagnosed, only about 50 percent show significant and effective improvement after treatment. Cancer, by contrast, receives enormous social attention. At least in developed countries, patients who are diagnosed with cancer are largely able to receive medical treatment. In terms of scientific research, there has been very little research on depression compared to the booming field of cancer research. Then the question arises: Why is depression not as painful as cancer, but people are far less concerned about it than cancer? 1. Support Scientific research often depends not only on human needs, but also on political, social, and economic factors that affect the balance of support for research on different diseases. The public’s call for the treatment of a certain disease will also attract more funds to this direction. Historically, the U.S. “War on Cancer” campaign was launched in 1971, and it has contributed to the development of cancer research. To date, however, there has not been a campaign similar to the “War on Depression” campaign. Any movement requires energy, but the nature of depression is such that patients are unable and unmotivated to fight it. At the same time, the long-standing stigma against depression makes it difficult to campaign against it. Professor Nelson of the University of California, Los Angeles, said: “A large part of the population believes that depression is not a disease, it’s just a bad emotion that we feel. Some people think that if you’re depressed, you just need to buck up and do a good job.” In contrast, people’s attitudes toward cancer are very different, and I believe it goes without saying that people understand the difference between the two. Depression and cancer are two very different diseases: cancer, or malignancy, can be detected, monitored and removed. But depression has no such characteristics. The human tissues affected by depression are closed in the brain, so it is difficult to be seen and even more difficult to be removed. All of these reasons make depression a difficult enemy to defeat. Happily, with the efforts of researchers, the definition and and diagnosis of depression is progressing. A research team from the United States is trying to recruit a group of depressed patients to summarize the typical symptoms of depression. They hope that the clarity of the symptoms can reduce the interference in the diagnosis, and eventually implement the diagnosis of depression to the biological level, so that depression becomes a disease like cancer or heart disease that can be clearly diagnosed and localized to the corresponding biological molecules. 2. Hope brought by genes With the strong development of cancer research, genetic methods have brought great help to cancer diagnosis, therefore, some researchers also hope that genetics can assist in diagnosing depression or subdividing different subtypes of depression. However, the reality is that there are still very few genetic studies and research results on depression. One of the largest genetic collections on depression so far has collected data from over 16,000 major depressive disorder and 60,000 normal individuals, resulting in the identification of only one gene locus that may be associated with depression. In fact, the essential reason for the poor development of such studies is the lack of clarity in the definition of depressive disorders. In addition, it is not clear whether the investment in genetics, a field that has only grown rapidly in the last decade, will yield the expected returns. All of these issues have hindered genetic research on depression. But hope remains, scientists have made progress in genetic research on mental illnesses such as schizophrenia, and it is believed that researchers will also make breakthroughs in genetic research on depression in the future. 3, animal experiments for depression Experiments on animals have always been an important tool in medical research. In cancer, a variety of animal studies have become a great help to promote the development of cancer research. However, in depression research, it is very difficult to use animal models to simulate depression and conduct experiments. Most animal studies of depression often use physical stress to create depressive symptoms in animals similar to those in humans, such as forcing animals to swim and observing the time it takes for them to give up their quest for survival. However, this research approach is far from ideal, because depression in humans is rarely caused by physical stress. In response to the shortcomings of this method, some researchers have also invented animal experiments that use social stress to cause depression. But even for the improved method, some scholars still question whether the use of animal experiments can really simulate depression well in humans. In fact, studies do show that such animal models are very different from human depression. We really know very little about depression, the only thing that is very clear is that depression is a mental illness with great complexity. 4. Neurocircuitry studies of depression As technology continues to advance, researchers have the high-tech means to explore biomolecules, so there is a group of scholars trying to reveal the causes of depression from the perspective of neurocircuitry. Neurocircuitry research uses electroencephalography or magnetoencephalography as a means to identify the neural circuits associated with depression and to try to improve depressive symptoms by altering the circuits. These direct approaches to neural circuits are more direct than traditional pharmacological treatments, but they also have more complex problems. In conclusion, depression brings great suffering and has a complex pathology and symptoms, but it is a disease that is in an awkward situation that needs to be addressed. People’s understanding of depression has to be changed and scientists need to solve many questions about depression. In order for hundreds of millions of depressed people to get out of depression and get happiness, we need more power to invest in depression-related research, and depression also needs everyone’s care and attention.