Both the sensory and the motivational-affective component of pain must be taken into account in studies on sex differences as well as on neuropathic, postoperative, sympathetic, and visceral pain. In all these cases, therapeutic strategies should be aimed at controlling the peripheral, central, and psychological mechanisms underlying the global pain experience. Similarly, it should be recalled that some neuropeptides act on both sensory and affective pain mechanisms. [berkley; mcmahon; dickenson; coderre & katz; wiesenfeld-hallin et al.; blumberg et al.]