There are four main causes. Frist is degradation and disease of the bodies. Many health problems will appear when people are getting old. It directly affects their life and moods. These involve physical and psychological factors. The disease such as thyroid problem and cerebrovascular disease can cause endocrine disorder. The emotion becomes unstable due to abnormal secretion of hormone. This is a pathological cause. The degradation of the body also lead to depression psychologically. The elderly usually have limited mobility. They lose the motivation and don’t want to move although they have the ability to go about the social activities. Another psychological factor is the pressure under chronic illness. The elderly lack knowledge about the illnesses. They may feel confused because they don’t know what treatment they receiving and what the prognosis are.These lead to negative thinking to the elderly. they may become excessively nervous and troubled.The second cause is loss of life goals after retirement, especially senior executives and professionals. They think their social status are lowered. Their social life are greatly reduced. The self-image changes. They may doubt whether they are the burden of the society. The third cause is the death of their spouses and close friends. They have to independently deal with all aspects of daily life since then. For example, a widower need to learn to cook the meal for himself after his wife was gone. They definitely feel grieved and lonely. They may also feel disturbed due to the fear of death. The last cause is financial stress. The elderly from the grass-roots lose the ability to work. And they have to pay for medical expenses. But they don’t want to increase the financial stress on their children to support themselves. So they can only scavenge the rubbish and sell them to earn money. Also, their savings and the allowance from government are insufficient for their daily life.So it is stressful for the elderly.