Introduction

Much recent research has focused on differences between the sexes in both physiology and behavior. The idea that differences between men and women can be attributable to biological factors that do not result from rearing or sociocultural variables is intriguing for many reasons, not the least of which is that it can help to explain sex differences in important health-related endpoints. One such endpoint is the experience of pain.

A consideration of the hormonal basis for gender differences in pain perception is relevant to a volume on the neuroendocrine aspects of aging for several reasons. One of the foremost observations of health care practitioners is the enormous degree of individual variability that exists among patients with respect to pain and analgesia. For example, some individuals continue to report pain following substantial doses of morphine (Lasagna & Beecher, 1954), while others exhibit significant pain relief following treatment with placebo (Beecher, 1959). As health care providers face aging populations, in whom chronic pain conditions and painful disease are increasingly prevalent, it is essential to understand the factors that contribute to such variability in order to effectively treat pain. Gender is one such factor.

Furthermore, a likely contributing factor to gender variability in pain experience is hormonal status, as will be discussed later in this chapter. Widespread changes in gonadal hormone levels, particularly in females, are characteristic of the aging process and may play a role in painful experience.