Sex differences in pain perception and anxiety. A psychophysical study with topical capsaicin

Much evidence indicates that women experience painful stimuli as more intense than men do. Nevertheless, some data suggest that sustained low-level pain may be more disturbing to men than to women. The current experiment evaluated the hypothesis that pain is more disturbing for men than for women by comparing across genders sensory and emotional aspects of pain evoked by capsaicin. Ten men and 10 women (aged 20-46 years) received topical capsaicin for 30 min on the face in one session and on the ankle in another. The subjects rated on visual analog scales pain intensity, unpleasantness and anxiety each minute during capsaicin application and for 30 min after its removal. During capsaicin application, females rated both pain intensity (P = 0.04) and unpleasantness (P = 0.05) higher than did males. Further, subjects rated pain intensity and unpleasantness higher on the face than on the ankle, although the physical stimulus was the same. Despite their lower pain ratings, men reported more pain-related anxiety than women (P = 0.02) Moreover, men showed a significant positive correlation between anxiety and pain intensity and unpleasantness, whereas women did not. After removing the capsaicin, there was no overall effect of sex on either intensity (P = 0.18) or unpleasantness (P = 0.37) of the residual sensation. However, men still showed a positive correlation between anxiety and the intensity and unpleasantness of the sensation. Our data confirm with the topical capsaicin model that women rate pain higher than men, but despite their lower pain ratings, males have more anxiety related to pain.