However, there are no consistent research results that explain women's greater involvement with pain. One problem is that studies measure pain reported to physicians by people seeking help, so that the results may be affected by different attitudes toward pain between men and women. Men perhaps feel obliged to live up to a cultural image of being tough and thus don't admit to pain; while the regular experience of menstrual pain that many women have may shape the ideas girls and women develop of what pain is and how best to cope with it. How much the sex differential has to do with differences in physiology between men and women, and how much it is shaped by social expectations of how women and men should behave, is therefore unknown.

It seems clear, however, that pain is a large issue for women, which must have some effect on their thinking and feeling. Here there is a great deal of research, which unfortunately does not tell us much beyond what common sense would suggest. "Persistence of pain," writes one expert, "can have a profoundly debilitating effect.... despondency and a sense of hopelessness become likely outcomes."

People with chronic pain often develop what is called "learned helplessness," a sense of having lost control not only over their pain but over life in general. Depression, low self-esteem, passivity, sadness, loss of appetite, aggression, and self-blame promote a vicious cycle in which negative thoughts and feelings generate more pain. Thoughts about pain may come to dominate people's thinking, so that they "label all sensations as 'pain,' " rather than discriminating between them, or they tend toward "catastrophizing," generating negative thoughts about themselves and their future.