Patients' direct experiences as central elements of placebo analgesia

Abstract

Placebo analgesic effects appear to be related to patients' perception of the therapeutic intervention. In this paper, we review quantitative findings of how the relationship with the physician and the verbal suggestions given for relief may influence patients' perception of a treatment and how patients' expectations and emotional feelings may affect treatment outcome. We also present qualitative data from interviews with patients who have experienced pain relief following a placebo or an active treatment. A special focus is given to the temporal development of placebo analgesia at psychological and neurophysiological levels. Finally, we discuss the extent to which the quantitative and qualitative findings supplement or contrast with each other, and we touch upon possible implications of patients' direct experience as central for placebo analgesia.

Unconscious and conscious mediation of analgesia and hyperalgesia

“…The increases did not occur in the IBS group not given the verbal suggestion. Taken together, these studies of IBS patients reflect the conscious cognitive nature of this form of analgesia (7)(8)(9). After all, the patients have to hear the verbal suggestion, understand its meanings, retain a working memory of it, and develop expectations and feelings about reduced pain (which they can rate on scales), unlike the mechanisms of subliminally conditioned changes in pain described by Jensen et al (1).…”

“…Do their psychological and neural mechanisms use brain areas that can also be activated without awareness of conditioning cues, such as those activated in Jensen et al's (1-3) studies? Verbally mediated analgesia and hyperalgesia entail conscious dimensions, such as expected pain reduction, desire for pain relief, and emotional feelings about prospects of pain increase or decrease (8). Some of these studies show that changes in pain are preceded by reduced ratings of expected pain in instances wherein analgesia is produced.…”

“…First, ratings of desire for relief and expected pain predicted most of the variability in pain ratings in the placebo condition (8). Second, ratings of expected pain, desire for pain reduction, and experimentally evoked pain (from visceral distension) progressively decreased with each successive test stimulus used to measure the placebo analgesic response (7)(8)(9). This progressive increase in placebo responding has been explained by a somatic feedback mechanism in which patients' experiences of pain relief lead to still further reductions in pain during subsequent test stimuli (12).…”

“…It is also important to recognize that placebo and nocebo effects on pain can occur consciously and without conditioning (7)(8)(9)(10). Consciously evoked pain modulation is known to occur as a result of verbal suggestions (7-10), as well as physical simulations of active treatments (4).…”

Introduction to placebo effects in medicine: mechanisms and clinical implications

“…Vase et al [64] present qualitative data from interviews with patients who have experienced pain relief following a placebo intervention or active treatment, discussing the extent to which these findings have implications for our understanding of placebo analgesia.…”